solar energy research articles

• Search Menu
• Advanced Articles
• Editor's Choice
• Author Guidelines
• Publish with us
• Submission Site
• Open Access
• Self-Archiving Policy
• About Clean Energy
• About the National Institute of Clean and Low-Carbon Energy
• Editorial Board
• Instructions for Reviewers
• Advertising & Corporate Services
• Journals Career Network
• Journals on Oxford Academic
• Books on Oxford Academic

Article Contents

Introduction, 1 installed capacity and application of solar energy worldwide, 2 the role of solar energy in sustainable development, 3 the perspective of solar energy, 4 conclusions, conflict of interest statement.

• < Previous

Solar energy technology and its roles in sustainable development

• Article contents
• Figures & tables
• Supplementary Data

Ali O M Maka, Jamal M Alabid, Solar energy technology and its roles in sustainable development, Clean Energy , Volume 6, Issue 3, June 2022, Pages 476–483, https://doi.org/10.1093/ce/zkac023

• Permissions Icon Permissions

Solar energy is environmentally friendly technology, a great energy supply and one of the most significant renewable and green energy sources. It plays a substantial role in achieving sustainable development energy solutions. Therefore, the massive amount of solar energy attainable daily makes it a very attractive resource for generating electricity. Both technologies, applications of concentrated solar power or solar photovoltaics, are always under continuous development to fulfil our energy needs. Hence, a large installed capacity of solar energy applications worldwide, in the same context, supports the energy sector and meets the employment market to gain sufficient development. This paper highlights solar energy applications and their role in sustainable development and considers renewable energy’s overall employment potential. Thus, it provides insights and analysis on solar energy sustainability, including environmental and economic development. Furthermore, it has identified the contributions of solar energy applications in sustainable development by providing energy needs, creating jobs opportunities and enhancing environmental protection. Finally, the perspective of solar energy technology is drawn up in the application of the energy sector and affords a vision of future development in this domain.

With reference to the recommendations of the UN, the Climate Change Conference, COP26, was held in Glasgow , UK, in 2021. They reached an agreement through the representatives of the 197 countries, where they concurred to move towards reducing dependency on coal and fossil-fuel sources. Furthermore, the conference stated ‘the various opportunities for governments to prioritize health and equity in the international climate movement and sustainable development agenda’. Also, one of the testaments is the necessity to ‘create energy systems that protect and improve climate and health’ [ 1 , 2 ].

The Paris Climate Accords is a worldwide agreement on climate change signed in 2015, which addressed the mitigation of climate change, adaptation and finance. Consequently, the representatives of 196 countries concurred to decrease their greenhouse gas emissions [ 3 ]. The Paris Agreement is essential for present and future generations to attain a more secure and stable environment. In essence, the Paris Agreement has been about safeguarding people from such an uncertain and progressively dangerous environment and ensuring everyone can have the right to live in a healthy, pollutant-free environment without the negative impacts of climate change [ 3 , 4 ].

In recent decades, there has been an increase in demand for cleaner energy resources. Based on that, decision-makers of all countries have drawn up plans that depend on renewable sources through a long-term strategy. Thus, such plans reduce the reliance of dependence on traditional energy sources and substitute traditional energy sources with alternative energy technology. As a result, the global community is starting to shift towards utilizing sustainable energy sources and reducing dependence on traditional fossil fuels as a source of energy [ 5 , 6 ].

In 2015, the UN adopted the sustainable development goals (SDGs) and recognized them as international legislation, which demands a global effort to end poverty, safeguard the environment and guarantee that by 2030, humanity lives in prosperity and peace. Consequently, progress needs to be balanced among economic, social and environmental sustainability models [ 7 ].

Many national and international regulations have been established to control the gas emissions and pollutants that impact the environment [ 8 ]. However, the negative effects of increased carbon in the atmosphere have grown in the last 10 years. Production and use of fossil fuels emit methane (CH 4 ), carbon dioxide (CO 2 ) and carbon monoxide (CO), which are the most significant contributors to environmental emissions on our planet. Additionally, coal and oil, including gasoline, coal, oil and methane, are commonly used in energy for transport or for generating electricity. Therefore, burning these fossil fuel s is deemed the largest emitter when used for electricity generation, transport, etc. However, these energy resources are considered depleted energy sources being consumed to an unsustainable degree [ 9–11 ].

Energy is an essential need for the existence and growth of human communities. Consequently, the need for energy has increased gradually as human civilization has progressed. Additionally, in the past few decades, the rapid rise of the world’s population and its reliance on technological developments have increased energy demands. Furthermore, green technology sources play an important role in sustainably providing energy supplies, especially in mitigating climate change [ 5 , 6 , 8 ].

Currently, fossil fuels remain dominant and will continue to be the primary source of large-scale energy for the foreseeable future; however, renewable energy should play a vital role in the future of global energy. The global energy system is undergoing a movement towards more sustainable sources of energy [ 12 , 13 ].

Power generation by fossil-fuel resources has peaked, whilst solar energy is predicted to be at the vanguard of energy generation in the near future. Moreover, it is predicted that by 2050, the generation of solar energy will have increased to 48% due to economic and industrial growth [ 13 , 14 ].

In recent years, it has become increasingly obvious that the globe must decrease greenhouse gas emissions by 2050, ideally towards net zero, if we are to fulfil the Paris Agreement’s goal to reduce global temperature increases [ 3 , 4 ]. The net-zero emissions complement the scenario of sustainable development assessment by 2050. According to the agreed scenario of sustainable development, many industrialized economies must achieve net-zero emissions by 2050. However, the net-zero emissions 2050 brought the first detailed International Energy Agency (IEA) modelling of what strategy will be required over the next 10 years to achieve net-zero carbon emissions worldwide by 2050 [ 15–17 ].

The global statistics of greenhouse gas emissions have been identified; in 2019, there was a 1% decrease in CO 2 emissions from the power industry; that figure dropped by 7% in 2020 due to the COVID-19 crisis, thus indicating a drop in coal-fired energy generation that is being squeezed by decreasing energy needs, growth of renewables and the shift away from fossil fuels. As a result, in 2020, the energy industry was expected to generate ~13 Gt CO 2 , representing ~40% of total world energy sector emissions related to CO 2 . The annual electricity generation stepped back to pre-crisis levels by 2021, although due to a changing ‘fuel mix’, the CO 2 emissions in the power sector will grow just a little before remaining roughly steady until 2030 [ 15 ].

Therefore, based on the information mentioned above, the advantages of solar energy technology are a renewable and clean energy source that is plentiful, cheaper costs, less maintenance and environmentally friendly, to name but a few. The significance of this paper is to highlight solar energy applications to ensure sustainable development; thus, it is vital to researchers, engineers and customers alike. The article’s primary aim is to raise public awareness and disseminate the culture of solar energy usage in daily life, since moving forward, it is the best. The scope of this paper is as follows. Section 1 represents a summary of the introduction. Section 2 represents a summary of installed capacity and the application of solar energy worldwide. Section 3 presents the role of solar energy in the sustainable development and employment of renewable energy. Section 4 represents the perspective of solar energy. Finally, Section 5 outlines the conclusions and recommendations for future work.

1.1 Installed capacity of solar energy

The history of solar energy can be traced back to the seventh century when mirrors with solar power were used. In 1893, the photovoltaic (PV) effect was discovered; after many decades, scientists developed this technology for electricity generation [ 18 ]. Based on that, after many years of research and development from scientists worldwide, solar energy technology is classified into two key applications: solar thermal and solar PV.

PV systems convert the Sun’s energy into electricity by utilizing solar panels. These PV devices have quickly become the cheapest option for new electricity generation in numerous world locations due to their ubiquitous deployment. For example, during the period from 2010 to 2018, the cost of generating electricity by solar PV plants decreased by 77%. However, solar PV installed capacity progress expanded 100-fold between 2005 and 2018. Consequently, solar PV has emerged as a key component in the low-carbon sustainable energy system required to provide access to affordable and dependable electricity, assisting in fulfilling the Paris climate agreement and in achieving the 2030 SDG targets [ 19 ].

The installed capacity of solar energy worldwide has been rapidly increased to meet energy demands. The installed capacity of PV technology from 2010 to 2020 increased from 40 334 to 709 674 MW, whereas the installed capacity of concentrated solar power (CSP) applications, which was 1266 MW in 2010, after 10 years had increased to 6479 MW. Therefore, solar PV technology has more deployed installations than CSP applications. So, the stand-alone solar PV and large-scale grid-connected PV plants are widely used worldwide and used in space applications. Fig. 1 represents the installation of solar energy worldwide.

Installation capacity of solar energy worldwide [ 20 ].

1.2 Application of solar energy

Energy can be obtained directly from the Sun—so-called solar energy. Globally, there has been growth in solar energy applications, as it can be used to generate electricity, desalinate water and generate heat, etc. The taxonomy of applications of solar energy is as follows: (i) PVs and (ii) CSP. Fig. 2 details the taxonomy of solar energy applications.

The taxonomy of solar energy applications.

Solar cells are devices that convert sunlight directly into electricity; typical semiconductor materials are utilized to form a PV solar cell device. These materials’ characteristics are based on atoms with four electrons in their outer orbit or shell. Semiconductor materials are from the periodic table’s group ‘IV’ or a mixture of groups ‘IV’ and ‘II’, the latter known as ‘II–VI’ semiconductors [ 21 ]. Additionally, a periodic table mixture of elements from groups ‘III’ and ‘V’ can create ‘III–V’ materials [ 22 ].

PV devices, sometimes called solar cells, are electronic devices that convert sunlight into electrical power. PVs are also one of the rapidly growing renewable-energy technologies of today. It is therefore anticipated to play a significant role in the long-term world electricity-generating mixture moving forward.

Solar PV systems can be incorporated to supply electricity on a commercial level or installed in smaller clusters for mini-grids or individual usage. Utilizing PV modules to power mini-grids is a great way to offer electricity to those who do not live close to power-transmission lines, especially in developing countries with abundant solar energy resources. In the most recent decade, the cost of producing PV modules has dropped drastically, giving them not only accessibility but sometimes making them the least expensive energy form. PV arrays have a 30-year lifetime and come in various shades based on the type of material utilized in their production.

The most typical method for solar PV desalination technology that is used for desalinating sea or salty water is electrodialysis (ED). Therefore, solar PV modules are directly connected to the desalination process. This technique employs the direct-current electricity to remove salt from the sea or salty water.

The technology of PV–thermal (PV–T) comprises conventional solar PV modules coupled with a thermal collector mounted on the rear side of the PV module to pre-heat domestic hot water. Accordingly, this enables a larger portion of the incident solar energy on the collector to be converted into beneficial electrical and thermal energy.

A zero-energy building is a building that is designed for zero net energy emissions and emits no carbon dioxide. Building-integrated PV (BIPV) technology is coupled with solar energy sources and devices in buildings that are utilized to supply energy needs. Thus, building-integrated PVs utilizing thermal energy (BIPV/T) incorporate creative technologies such as solar cooling [ 23 ].

A PV water-pumping system is typically used to pump water in rural, isolated and desert areas. The system consists of PV modules to power a water pump to the location of water need. The water-pumping rate depends on many factors such as pumping head, solar intensity, etc.

A PV-powered cathodic protection (CP) system is designed to supply a CP system to control the corrosion of a metal surface. This technique is based on the impressive current acquired from PV solar energy systems and is utilized for burying pipelines, tanks, concrete structures, etc.

Concentrated PV (CPV) technology uses either the refractive or the reflective concentrators to increase sunlight to PV cells [ 24 , 25 ]. High-efficiency solar cells are usually used, consisting of many layers of semiconductor materials that stack on top of each other. This technology has an efficiency of >47%. In addition, the devices produce electricity and the heat can be used for other purposes [ 26 , 27 ].

For CSP systems, the solar rays are concentrated using mirrors in this application. These rays will heat a fluid, resulting in steam used to power a turbine and generate electricity. Large-scale power stations employ CSP to generate electricity. A field of mirrors typically redirect rays to a tall thin tower in a CSP power station. Thus, numerous large flat heliostats (mirrors) are used to track the Sun and concentrate its light onto a receiver in power tower systems, sometimes known as central receivers. The hot fluid could be utilized right away to produce steam or stored for later usage. Another of the great benefits of a CSP power station is that it may be built with molten salts to store heat and generate electricity outside of daylight hours.

Mirrored dishes are used in dish engine systems to focus and concentrate sunlight onto a receiver. The dish assembly tracks the Sun’s movement to capture as much solar energy as possible. The engine includes thin tubes that work outside the four-piston cylinders and it opens into the cylinders containing hydrogen or helium gas. The pistons are driven by the expanding gas. Finally, the pistons drive an electric generator by turning a crankshaft.

A further water-treatment technique, using reverse osmosis, depends on the solar-thermal and using solar concentrated power through the parabolic trough technique. The desalination employs CSP technology that utilizes hybrid integration and thermal storage allows continuous operation and is a cost-effective solution. Solar thermal can be used for domestic purposes such as a dryer. In some countries or societies, the so-called food dehydration is traditionally used to preserve some food materials such as meats, fruits and vegetables.

Sustainable energy development is defined as the development of the energy sector in terms of energy generating, distributing and utilizing that are based on sustainability rules [ 28 ]. Energy systems will significantly impact the environment in both developed and developing countries. Consequently, the global sustainable energy system must optimize efficiency and reduce emissions [ 29 ].

The sustainable development scenario is built based on the economic perspective. It also examines what activities will be required to meet shared long-term climate benefits, clean air and energy access targets. The short-term details are based on the IEA’s sustainable recovery strategy, which aims to promote economies and employment through developing a cleaner and more reliable energy infrastructure [ 15 ]. In addition, sustainable development includes utilizing renewable-energy applications, smart-grid technologies, energy security, and energy pricing, and having a sound energy policy [ 29 ].

The demand-side response can help meet the flexibility requirements in electricity systems by moving demand over time. As a result, the integration of renewable technologies for helping facilitate the peak demand is reduced, system stability is maintained, and total costs and CO 2 emissions are reduced. The demand-side response is currently used mostly in Europe and North America, where it is primarily aimed at huge commercial and industrial electricity customers [ 15 ].

International standards are an essential component of high-quality infrastructure. Establishing legislative convergence, increasing competition and supporting innovation will allow participants to take part in a global world PV market [ 30 ]. Numerous additional countries might benefit from more actively engaging in developing global solar PV standards. The leading countries in solar PV manufacturing and deployment have embraced global standards for PV systems and highly contributed to clean-energy development. Additional assistance and capacity-building to enhance quality infrastructure in developing economies might also help support wider implementation and compliance with international solar PV standards. Thus, support can bring legal requirements and frameworks into consistency and give additional impetus for the trade of secure and high-quality solar PV products [ 19 ].

Continuous trade-led dissemination of solar PV and other renewable technologies will strengthen the national infrastructure. For instance, off-grid solar energy alternatives, such as stand-alone systems and mini-grids, could be easily deployed to assist healthcare facilities in improving their degree of services and powering portable testing sites and vaccination coolers. In addition to helping in the immediate medical crisis, trade-led solar PV adoption could aid in the improving economy from the COVID-19 outbreak, not least by providing jobs in the renewable-energy sector, which are estimated to reach >40 million by 2050 [ 19 ].

The framework for energy sustainability development, by the application of solar energy, is one way to achieve that goal. With the large availability of solar energy resources for PV and CSP energy applications, we can move towards energy sustainability. Fig. 3 illustrates plans for solar energy sustainability.

Framework for solar energy applications in energy sustainability.

The environmental consideration of such applications, including an aspect of the environmental conditions, operating conditions, etc., have been assessed. It is clean, friendly to the environment and also energy-saving. Moreover, this technology has no removable parts, low maintenance procedures and longevity.

Economic and social development are considered by offering job opportunities to the community and providing cheaper energy options. It can also improve people’s income; in turn, living standards will be enhanced. Therefore, energy is paramount, considered to be the most vital element of human life, society’s progress and economic development.

As efforts are made to increase the energy transition towards sustainable energy systems, it is anticipated that the next decade will see a continued booming of solar energy and all clean-energy technology. Scholars worldwide consider research and innovation to be substantial drivers to enhance the potency of such solar application technology.

2.1 Employment from renewable energy

The employment market has also boomed with the deployment of renewable-energy technology. Renewable-energy technology applications have created >12 million jobs worldwide. The solar PV application came as the pioneer, which created >3 million jobs. At the same time, while the solar thermal applications (solar heating and cooling) created >819 000 jobs, the CSP attained >31 000 jobs [ 20 ].

According to the reports, although top markets such as the USA, the EU and China had the highest investment in renewables jobs, other Asian countries have emerged as players in the solar PV panel manufacturers’ industry [ 31 ].

Solar energy employment has offered more employment than other renewable sources. For example, in the developing countries, there was a growth in employment chances in solar applications that powered ‘micro-enterprises’. Hence, it has been significant in eliminating poverty, which is considered the key goal of sustainable energy development. Therefore, solar energy plays a critical part in fulfilling the sustainability targets for a better plant and environment [ 31 , 32 ]. Fig. 4 illustrates distributions of world renewable-energy employment.

World renewable-energy employment [ 20 ].

The world distribution of PV jobs is disseminated across the continents as follows. There was 70% employment in PV applications available in Asia, while 10% is available in North America, 10% available in South America and 10% availability in Europe. Table 1 details the top 10 countries that have relevant jobs in Asia, North America, South America and Europe.

List of the top 10 countries that created jobs in solar PV applications [ 19 , 33 ]

Solar energy investments can meet energy targets and environmental protection by reducing carbon emissions while having no detrimental influence on the country’s development [ 32 , 34 ]. In countries located in the ‘Sunbelt’, there is huge potential for solar energy, where there is a year-round abundance of solar global horizontal irradiation. Consequently, these countries, including the Middle East, Australia, North Africa, China, the USA and Southern Africa, to name a few, have a lot of potential for solar energy technology. The average yearly solar intensity is >2800 kWh/m 2 and the average daily solar intensity is >7.5 kWh/m 2 . Fig. 5 illustrates the optimum areas for global solar irradiation.

World global solar irradiation map [ 35 ].

The distribution of solar radiation and its intensity are two important factors that influence the efficiency of solar PV technology and these two parameters vary among different countries. Therefore, it is essential to realize that some solar energy is wasted since it is not utilized. On the other hand, solar radiation is abundant in several countries, especially in developing ones, which makes it invaluable [ 36 , 37 ].

Worldwide, the PV industry has benefited recently from globalization, which has allowed huge improvements in economies of scale, while vertical integration has created strong value chains: as manufacturers source materials from an increasing number of suppliers, prices have dropped while quality has been maintained. Furthermore, the worldwide incorporated PV solar device market is growing fast, creating opportunities enabling solar energy firms to benefit from significant government help with underwriting, subsides, beneficial trading licences and training of a competent workforce, while the increased rivalry has reinforced the motivation to continue investing in research and development, both public and private [ 19 , 33 ].

The global outbreak of COVID-19 has impacted ‘cross-border supply chains’ and those investors working in the renewable-energy sector. As a result, more diversity of solar PV supply-chain processes may be required in the future to enhance long-term flexibility versus exogenous shocks [ 19 , 33 ].

It is vital to establish a well-functioning quality infrastructure to expand the distribution of solar PV technologies beyond borders and make it easier for new enterprises to enter solar PV value chains. In addition, a strong quality infrastructure system is a significant instrument for assisting local firms in meeting the demands of trade markets. Furthermore, high-quality infrastructure can help reduce associated risks with the worldwide PV project value chain, such as underperforming, inefficient and failing goods, limiting the development, improvement and export of these technologies. Governments worldwide are, at various levels, creating quality infrastructure, including the usage of metrology i.e. the science of measurement and its application, regulations, testing procedures, accreditation, certification and market monitoring [ 33 , 38 ].

The perspective is based on a continuous process of technological advancement and learning. Its speed is determined by its deployment, which varies depending on the scenario [ 39 , 40 ]. The expense trends support policy preferences for low-carbon energy sources, particularly in increased energy-alteration scenarios. Emerging technologies are introduced and implemented as quickly as they ever have been before in energy history [ 15 , 33 ].

The CSP stations have been in use since the early 1980s and are currently found all over the world. The CSP power stations in the USA currently produce >800 MW of electricity yearly, which is sufficient to power ~500 000 houses. New CSP heat-transfer fluids being developed can function at ~1288 o C, which is greater than existing fluids, to improve the efficiency of CSP systems and, as a result, to lower the cost of energy generated using this technology. Thus, as a result, CSP is considered to have a bright future, with the ability to offer large-scale renewable energy that can supplement and soon replace traditional electricity-production technologies [ 41 ]. The DESERTEC project has drawn out the possibility of CSP in the Sahara Desert regions. When completed, this investment project will have the world’s biggest energy-generation capacity through the CSP plant, which aims to transport energy from North Africa to Europe [ 42 , 43 ].

The costs of manufacturing materials for PV devices have recently decreased, which is predicted to compensate for the requirements and increase the globe’s electricity demand [ 44 ]. Solar energy is a renewable, clean and environmentally friendly source of energy. Therefore, solar PV application techniques should be widely utilized. Although PV technology has always been under development for a variety of purposes, the fact that PV solar cells convert the radiant energy from the Sun directly into electrical power means it can be applied in space and in terrestrial applications [ 38 , 45 ].

In one way or another, the whole renewable-energy sector has a benefit over other energy industries. A long-term energy development plan needs an energy source that is inexhaustible, virtually accessible and simple to gather. The Sun rises over the horizon every day around the globe and leaves behind ~108–1018 kWh of energy; consequently, it is more than humanity will ever require to fulfil its desire for electricity [ 46 ].

The technology that converts solar radiation into electricity is well known and utilizes PV cells, which are already in use worldwide. In addition, various solar PV technologies are available today, including hybrid solar cells, inorganic solar cells and organic solar cells. So far, solar PV devices made from silicon have led the solar market; however, these PVs have certain drawbacks, such as expenditure of material, time-consuming production, etc. It is important to mention here the operational challenges of solar energy in that it does not work at night, has less output in cloudy weather and does not work in sandstorm conditions. PV battery storage is widely used to reduce the challenges to gain high reliability. Therefore, attempts have been made to find alternative materials to address these constraints. Currently, this domination is challenged by the evolution of the emerging generation of solar PV devices based on perovskite, organic and organic/inorganic hybrid materials.

This paper highlights the significance of sustainable energy development. Solar energy would help steady energy prices and give numerous social, environmental and economic benefits. This has been indicated by solar energy’s contribution to achieving sustainable development through meeting energy demands, creating jobs and protecting the environment. Hence, a paramount critical component of long-term sustainability should be investigated. Based on the current condition of fossil-fuel resources, which are deemed to be depleting energy sources, finding an innovative technique to deploy clean-energy technology is both essential and expected. Notwithstanding, solar energy has yet to reach maturity in development, especially CSP technology. Also, with growing developments in PV systems, there has been a huge rise in demand for PV technology applications all over the globe. Further work needs to be undertaken to develop energy sustainably and consider other clean energy resources. Moreover, a comprehensive experimental and validation process for such applications is required to develop cleaner energy sources to decarbonize our planet.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

World Health Organization . COP26 Special Report on Climate Change and Health: The Health Argument for Climate Action. Geneva : World Health Organization , 2021 .

Google Scholar

Google Preview

Hunter DB , Salzman JE , Zaelke D . Glasgow Climate Summit: COP26. UCLA School of Law, Public Law Research Paper No. 22-02. 2021 . doi: org/10.2139/ssrn.4005648 30 March 2022 , date last accessed).

UNFCCC . Paris Agreement-Status of Ratification, United Nations Framework Convention on Climate , 2016 . https://unfccc.int/process/the-paris-agreement/status-of-ratification ( 25 January 2022 , date last accessed).

UNFCCC . The Paris Agreement. Archived from the original on 19 March 2021 . Retrieved 18 September 2021 . https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement ( 2 February 2022 , date last accessed).

Watts RG. Engineering Response to Climate Change. 2nd edn. Boca Raton, FL : CRC Press , 2013 .

Sorensen B. Renewable Energy: Physics, Engineering, Environmental Impacts, Economics and Planning . 4th edn. London : Academic Press , 2010 .

IEA, IRENA, WMO, WBG, WHO . Tracking SDG7: The Energy Progress Report 2021. Washington, DC : The World Bank , 2021 .

Edenhofer O , Pichs-Madruga R , Sokona Y , et al.  Renewable Energy Sources and Climate Change Mitigation: Special Report of the Intergovernmental Panel on Climate Change. Cambridge : Cambridge University Press , 2011 .

Roaf S , Roaf S , Crichton D , et al.  Adapting buildings and Cities for Climate Change: A 21st Century Survival Guide . 2nd edn. Oxford : Architectural Press , 2009 .

Sims RE . Renewable energy: a response to climate change . Solar Energy , 2004 , 76 : 9 – 17 .

Muneer T. Solar Radiation and Daylight Models. 2nd edn, London : Routledge , 2004 .

Martin J . ‘Green growth’: from a growing eco-industry to economic sustainability . Energy Policy , 2012 , 48 : 13 – 21 .

IRENA. A Roadmap to 2050: International Renewable Energy Agency: Global energy Transformation. Abu Dhabi : IRENA , 2018 .

Kost C , Mayer JN , Thomsen J , et al.  Levelized Cost of Electricity Renewable Energy Technologies. Freiburg : Fraunhofer Institute for Solar Energy Systems (ISE), 2013 , 144 .

Cozzi L , Gould T , Bouckart S , et al.  World Energy Outlook 2020. Paris : International Energy Agency , 2020 .

Ku AY , de Souza A , McRobie J , et al.  Zero-emission public transit could be a catalyst for decarbonization of the transportation and power sectors . Clean Energy , 2021 , 5 : 492 – 504 .

Bouckaert S , Pales AF , McGlade C , et al.  Net Zero by 2050: A Roadmap for the Global Energy Sector. Paris : International Energy Agency , 2021 .

Fraas LM . History of solar cell development . Low-cost Solar Electric Power. 2014 : 1 – 12 . doi: 10.1007/978-3-319-07530-31 .

Gahrens S , Alessandra S , Steinfatt K. Trading Into a Bright Energy Future. The Case for Open, High-Quality Solar Photovoltaic Markets . Abu Dhabi : IRENA , 2021 , 1 – 44 . https://irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_WTO_Trading_Energy_Future_2021.pdf ( 21 April 2022 , date last accessed).

IRENA . Solar Energy—International Renewable Energy Agency . 2021 . www.irena.org/solar ( 2 February 2022 , date last accessed).

Honsberg C , Bowden S . Sun Position Calculator . 2014 . http://pveducation org/pvcdrom/properties-of-sunlight/sun-position-calculator ( 25 January 2022 , date last accessed).

Green MA , Hishikawa Y , Dunlop ED , et al.  Solar cell efficiency tables (version 52) . Progress in Photovoltaics , 2018 , 26 : 427 – 436 .

Kylili A , Fokaides PA . Investigation of building integrated photovoltaics potential in achieving the zero energy building target . Indoor Built Environment , 2014 , 23 : 92 – 106 .

Maka AO , O’Donovan TS . A review of thermal load and performance characterisation of a high concentrating photovoltaic (HCPV) solar receiver assembly . Solar Energy , 2020 , 206 : 35 – 51 .

Mohamed ET , Maka AO , Mehmood M , et al.  Performance simulation of single and dual-junction GaInP/GaAs tandem solar cells using AMPS-1D . Sustainable Energy Technologies Assessments , 2021 , 44 : 101067 .

Maka AO , O’Donovan TS . Dynamic performance analysis of solar concentrating photovoltaic receiver by coupling of weather data with the thermal-electrical model . Thermal Science Engineering Progress , 2021 , 24 : 100923 .

Maka AO , O’Donovan TS . Transient thermal-electrical performance modelling of solar concentrating photovoltaic (CPV) receiver . Solar Energy , 2020 , 211 : 897 – 907 .

Radovanovic M , Popov S , Dodic S. Sustainable Energy Management. Cambridge, MA : Academic Press , 2012 .

Salvarli MS , Salvarli H . For sustainable development: future trends in renewable energy and enabling technologies . In: Al Al Qubeissi M, El-kharouf A, Soyhan HS (eds). Qubeissi M , El-kharouf A , Soyhan HS (eds). Renewable Energy-Resources, Challenges and Applications . London : IntechOpen , 2020 .

Maka AO , Salem S , Mehmood M . Solar photovoltaic (PV) applications in Libya: challenges, potential, opportunities and future perspectives . Cleaner Engineering Technology , 2021 , 51 : 100267 .

IRENA . Renewable Energy and Jobs—Annual Review 2021, (REJ) . 2021 . https://www.irena.org/publications/2021/Oct/Renewable-Energy-and-Jobs-Annual-Review-2021 ( 2 January 2022 , date last accessed).

Obaideen K , AlMallahi MN , Alami AH , et al.  On the contribution of solar energy to sustainable developments goals: case study on Mohammed bin Rashid Al Maktoum Solar Park . International Journal of Thermofluids , 2021 , 12 : 100123 .

IRENA . International Renewable Energy Agency, Renewable Energy and Jobs—Annual Review 2020. Abu Dhabi : IRENA , 2020 .

Strielkowski W , Civín L , Tarkhanova E , et al.  Renewable energy in the sustainable development of electrical power sector: a review . Energies , 2021 , 14 : 8240 .

Grid-Arendal . Natural Resources—Solar Power (Potential) . 2008 . https://www.grida.no/resources/7308 ( 9 February 2022 , date last accessed).

Kannan N , Vakeesan D . Solar energy for future world: a review . Renewable Sustainable Energy Reviews , 2016 , 62 : 1092 – 1105 .

Löf GO , Duffie JA , Smith CO . World distribution of solar radiation . Solar Energy , 1966 , 10 : 27 – 37 .

Kabir E , Kumar P , Kumar S , et al.  Solar energy: potential and future prospects . Renewable Sustainable Energy Reviews , 2018 , 82 : 894 – 900 .

Johansson TB , Goldemberg J. Energy for Sustainable Development: A Policy Agenda. New York : United Nations Development Programme (UNDP) , 2002 .

Lowe R , Drummond P . Solar, wind and logistic substitution in global energy supply to 2050—barriers and implications . Renewable Sustainable Energy Reviews , 2022 , 153 : 111720 .

Asmelash E , Prakash G. Future of Solar Photovoltaic: Deployment, Investment, Technology, Grid Integration and Socio-economic Aspects . Abu Dhabi : IRENA , 2019 .

Griffiths S . Strategic considerations for deployment of solar photovoltaics in the Middle East and North Africa . Energy Strategy Reviews , 2013 , 2 : 125 – 131 .

Hafner M , Tagliapietra S , El Andaloussi EH . Outlook for Electricity and Renewable Energy in Southern and Eastern Mediterranean Countries. WP4b, Energy and Climate Change Mitigations, MEDPROTechnical Report No. 16/October 2012 . www.medpro-foresight.eu ( 25 January 2022 , date last accessed).

Martí A , Luque A. Next Generation Photovoltaics: High Efficiency Through Full Spectrum Utilization . 1st edn. Boca Raton, FL : CRC Press , 2003 .

Dimroth F , Kurtz S . High-efficiency multijunction solar cells . MRS Bulletin , 2007 , 32 : 230 – 235 .

Kashmir J . Solar Energy for Sustainable Development . 2018 . https://www.dailyexcelsior.com/solar-energy-sustainable-development/ ( 15 January 2022 , date last accessed).

Email alerts

Citing articles via.

• Advertising and Corporate Services

Affiliations

• Online ISSN 2515-396X
• Print ISSN 2515-4230
• Copyright © 2024 National Institute of Clean-and-Low-Carbon Energy
• About Oxford Academic
• Publish journals with us
• University press partners
• What we publish
• New features  
• Open access
• Institutional account management
• Rights and permissions
• Get help with access
• Accessibility
• Advertising
• Media enquiries
• Oxford University Press
• Oxford Languages
• University of Oxford

Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide

• Copyright © 2024 Oxford University Press
• Cookie settings
• Cookie policy
• Privacy policy
• Legal notice

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

• Future Energy Systems Center
• Studies and reports
• Funding opportunities
• Basic energy science
• Built environment and infrastructure
• Climate and environment
• Conventional energy
• Developing world
• Energy efficiency
• Nuclear energy
• Policy and economics
• Power distribution and energy storage
• Renewable energy
• Transportation
• Undergraduate education
• Graduate & postdoctoral
• Online education
• Education research
• Current members
• Energy Futures
• In the media
• Affiliations

The Future of Solar Energy

Read the report.

Executive summary (PDF) Full report (PDF)

The Future of Solar Energy considers only the two widely recognized classes of technologies for converting solar energy into electricity — photovoltaics (PV) and concentrated solar power (CSP), sometimes called solar thermal) — in their current and plausible future forms. Because energy supply facilities typically last several decades, technologies in these classes will dominate solar-powered generation between now and 2050, and we do not attempt to look beyond that date. In contrast to some earlier Future of studies, we also present no forecasts — for two reasons. First, expanding the solar industry dramatically from its relatively tiny current scale may produce changes we do not pretend to be able to foresee today. Second, we recognize that future solar deployment will depend heavily on uncertain future market conditions and public policies — including but not limited to policies aimed at mitigating global climate change.

As in other studies in this series, our primary aim is to inform decision-makers in the developed world, particularly the United States. We concentrate on the use of grid-connected solar-powered generators to replace conventional sources of electricity. For the more than one billion people in the developing world who lack access to a reliable electric grid, the cost of small-scale PV generation is often outweighed by the very high value of access to electricity for lighting and charging mobile telephone and radio batteries. In addition, in some developing nations it may be economic to use solar generation to reduce reliance on imported oil, particularly if that oil must be moved by truck to remote generator sites. A companion working paper discusses both these valuable roles for solar energy in the developing world.

Related publications

Shaping photovoltaic array output to align with changing wholesale electricity price profiles

December 2019

Spatial and temporal variation in the value of solar power across United States electricity markets

Solar heating for residential and industrial processes

Related news

MIT Energy Initiative Director Robert Armstrong shares perspectives on past successes and ongoing and future energy projects at the Institute.

• News & Events
• Contact & Visit
• Faculty & Staff
• McCormick Advisory Council
• Departments & Institutes
• Diversity Data
• Faculty Journal Covers
• Areas of Study
• Bachelor's Degrees
• Music & Engineering
• Combined BS / MS Program Collapse Combined BS / MS Program Submenu
• Murphy Scholars Program Projects
• Undergraduate Honors
• Certificates & Minors Collapse Certificates & Minors Submenu
• Integrated Engineering Studies
• Engineering First® Program
• Theme Requirement
• Research Opportunities
• Personal & Career Development
• Global Opportunities
• Existing Groups
• McCormick Community
• Transfer AP/IB Credits
• ABET Course Partitioning
• Enrollment and Graduation Data
• Full-time Master's
• Part-time Master's
• MS with Interdepartmental Minors
• Application Checklist
• Application FAQs
• Financial Aid
• International Students
• Student Groups
• Career & Professional Development
• All Areas of Study
• Departments & Programs
• Apply to Northwestern Engineering
• Faculty Fellows
• Office of the Dean
• Administration, Finance, Facilities, & Planning
• Alumni Relations & Development
• Career Development
• Corporate Engagement
• Customer Service Center
• Faculty Affairs
• Global Initiatives
• Graduate Studies
• Information Technology
• Marketing & Communications
• McCormick Advising System
• Personal Development StudioLab
• Professional Education
• Research Offices
• Undergraduate Engineering
• Newsletter Signup
• Information for the Media
• Tech Room Finder

Researchers Take a Step Closer to Better, More Affordable Solar Cells

Innovative technique leads to perovskite-based solar cells with record-breaking efficiency, the problem:.

Scaling single-junction perovskite solar cells (PSCs) has been challenging.

A new technique applied during crystal formation that allows PSCs with an ‘inverted’ or ‘pin’ structure – known for their stability – to exhibit high efficiency.

Why it Matters:

The breakthrough means PSCs are closer to scaling, bringing them nearer their potential to contribute to the decarbonization of the electricity supply.

Professor Ted Sargent, Research Assistant Professor Bin Chen, Postdoctoral Researcher Hao Chen, Postdoctoral Fellow Cheng Liu

An international team of researchers, including a group from Northwestern Engineering and Northwestern Chemistry , has set a new world record for power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs).

These solar cells – created from an emerging solar material – have the potential to generate greater solar energy at a lower cost than today’s industry-standard silicon solar cells, but scaling the technology has its challenges. Until now, PSCs have shown either high stability and lower efficiency or vice versa, depending on their structure.

Yet this team’s work has resulted in a highly stable, highly efficient 0.05cm 2 perovskite solar cell with a PCE of 26.15 percent certified by a National Renewable Energy Laboratory -accredited facility. The prior certified world record published in a scientific journal was 25.73 percent.

A 1.04 cm 2 device had a certified power conversion efficiency of 24.74 percent, also a record for its size. The best devices retained 95 percent of their initial PCE following 1,200 hours of continuous solar illumination at a temperature of 65 degrees.

“Perovskite-based solar cells have the potential to contribute to the decarbonization of the electricity supply once we finalize their design, achieve the union of performance and durability, and scale the devices,” said Ted Sargent , Lynn Hopton Davis and Greg Davis Professor of Chemistry and Electrical and Computer Engineering at Northwestern University, co-executive director of the Paula M. Trienens Institute for Sustainability and Energy , and co-corresponding author of the paper. “Our team has discovered a new technique applied during crystal formation that allows PSCs with an ‘inverted’ or ‘pin’ structure – known for their stability – to exhibit high efficiency. It’s the best of both worlds.”

Our team has discovered a new technique applied during crystal formation that allows perovskite solar cells with an ‘inverted’ or ‘pin’ structure – known for their stability – to exhibit high efficiency. It’s the best of both worlds.

Ted Sargent Lynn Hopton Davis and Greg Davis Professor of Chemistry and Electrical and Computer Engineering

"Until today, a promising and more stable perovskite solar cell - inverted perovskite solar cells - have suffered lower energy efficiencies than those achieved in their non-inverted counterparts. This work represents an important milestone by crossing the efficiency-parity threshold," said Zhijun Ning, co-corresponding author and assistant professor at ShanghaiTech University.

Findings were reported April 11 in the journal Science.

A new approach to treating defects

The basic structure of “inverted” PSCs consists of an outer electron-transporting layer (ETL), a hole transporting layer (HTL), an anode, and a cathode. The energetic losses for the cells occur primarily at the interfaces between the perovskites and the ETL and HTL layers in places where there are tiny defects in the crystals.

Prior attempts at reducing energy loss have included the use of additive or surface treatments to passivate the defects. Sargent’s team noted that the molecules in these treatments bonded at a single site on the defects in a perpendicular orientation, forcing the electrons to travel a long distance up through the material, causing resistance and lowering efficiency.

The team set out to find a molecule that would bond on two neighboring sites on the defects in a horizontal orientation, reducing the distance the electrons needed to travel and improving efficiency. They identified one molecule – 4- chlorobenzenesulfonate – that could lay down at the surface of the perovskites by forming strong Cl-Pb and SO 3 -Pb bonds with the undercoordinated Pb 2+ and led to improved performance of the devices.

“By carefully selecting molecules that lie flat on the perovskite surface, binding to two sites simultaneously, our new strategy reduced the interface resistance:  the result is much higher fill factor in solar cells, reaching 95 percent of the theoretical limit," said Jian Xu, co-first author and postdoctoral fellow at the University of Toronto.

“Not only did the addition of these molecules improve efficiency, they also simplified the manufacturing process,” noted Hao Chen , a postdoctoral researcher at Northwestern Engineering and co-first author of the paper. “When added to the perovskites precursor, these molecules automatically go to the surface of the perovskite layer to patch defects during the crystallization process. This removes the need to treat the surface defects, an extra step that often results in uneven coverage of passivators and poor stability of the devices.”

This discovery builds on prior research conducted by the Sargent Group , which has explored various strategies to improve PSC performance and stability to make them a viable alternative to silicon solar cells. Next, the team will look toward scaling the devices.

“Northwestern is really at the forefront of renewable energy technology research,” said Bin Chen , co-corresponding author and research assistant professor at Northwestern Engineering. “By focusing on stable inverted perovskites and making breakthroughs in their performance, we are  developing a solar technology that can be a gamechanger in the field.”

"With the efficiency discrepancy solved, the large and growing perovskite community will focus even more of its firepower on the inverted perovskite solar cell architecture in light of its stability advantages," said Aidan Maxwell, co-first author of the paper and a graduate student at the University of Toronto.

“We were thrilled when we achieved an independently certified efficiency of 26.1 percent for inverted perovskite solar cells: this was the first to surpass the record for the conventional structure,” added Cheng Liu , postdoctoral fellow at Northwestern Chemistry and co-first author of the paper. “The accomplishment motivates not only our own team but will also inspires further collective efforts across the wide and productive global perovskite community."

Additional authors on the paper include Yi Yang, Abdulaziz S. R. Bati, Yuan Liu, and Mercouri G. Kanatzidis of Northwestern Chemistry; Haoyue Wan, Zaiwei Wang, Lewei Zeng, Junke Wang, Sam Teale, Yanjiang Liu, Sjoerd Hoogland, Peter Serles, and Tobin Filleter of the University of Toronto; Wei Zhou and Qilin Zhou of ShanghaiTech University; Makhsud I. Saidaminov of the University of Victoria; and Muzhi Li and Nicholas Rolston of Arizona State University.

Get our news in your inbox.

Sign up for our newsletter.

Check out our magazine.

Find more in depth stories and get to know Northwestern Engineering.

Solar Energy News

Top headlines, latest headlines.

• Heat, Cold Extremes: Solar, Wind Energy Use
• Pairing Crypto Mining With Green Hydrogen
• Reimagining the Future of Solar Energy
• New High-Performance Solar Cell Material
• Extremely Efficient Solar Cells
• Next-Generation Solar Cells
• More Stable Perovskite Solar Cells
• Improving Solar Cell Efficiency
• Breakthrough in Production of Green Hydrogen
• China: Reaching Carbon Neutrality by 2060?

Earlier Headlines

Friday, april 19, 2024.

• A Flexible and Efficient DC Power Converter for Sustainable-Energy Microgrids

Thursday, March 14, 2024

• Perovskite Solar Cells: Vacuum Process May Offer a Short Track to Commercialization

Monday, February 26, 2024

• New World Record for CIGS Solar Cells

Wednesday, February 21, 2024

• New Evidence Shows UK Solar Parks Can Provide for Bees and Butterflies
• Revolutionary Breakthrough in Solar Energy: Most Efficient QD Solar Cells
• Scientists Invent Ultra-Thin, Minimally-Invasive Pacemaker Controlled by Light

Tuesday, February 20, 2024

• Physicists Develop More Efficient Solar Cell

Friday, February 16, 2024

• Electrification or Hydrogen? Both Have Distinct Roles in the European Energy Transition

Monday, January 22, 2024

• New Sustainable Method for Creating Organic Semiconductors
• Breakthrough Research Enhances Stability and Efficiency of Perovskite Solar Cells

Wednesday, January 17, 2024

• Artificial 'power Plants' Harness Energy from Wind and Rain
• Space Solar Power Project Ends First in-Space Mission With Successes and Lessons

Tuesday, January 16, 2024

• Advancement in Thermoelectricity Could Light Up the Internet of Things

Thursday, January 11, 2024

• Bulky Additives Could Make Cheaper Solar Cells Last Longer

Wednesday, January 10, 2024

• New Findings Regarding the High Efficiency of Perovskite Solar Cells

Tuesday, January 9, 2024

• Green Wheels, Bright Skies: Analysis Unveils the Connection Between Electric Vehicles and Photovoltaics

Thursday, January 4, 2024

• High-Performance Stretchable Solar Cells

Wednesday, January 3, 2024

• Nature-Inspired Advanced Materials Achieves 99.6% Solar Reflectivity

Wednesday, December 13, 2023

• The Solar Forest

Tuesday, December 12, 2023

• Free Electric Vehicle Charging at Work? It's Possible With Optimum Solar

Monday, December 11, 2023

• 'Energy Droughts' In Wind and Solar Can Last Nearly a Week

Friday, December 8, 2023

• Polyethylene Waste Could Be a Thing of the Past

Friday, December 1, 2023

• Harvesting More Solar Energy With Supercrystals

Thursday, November 30, 2023

• Smart Microgrids Can Restore Power More Efficiently and Reliably in an Outage

Monday, November 27, 2023

• Promising Salt for Heat Storage

Wednesday, November 22, 2023

• Revolutionary Breakthrough in the Manufacture of Photovoltaic Cells
• AI for Perovskite Solar Cells: Key to Better Manufacturing

Thursday, November 16, 2023

• No One-Size-Fits-All Solution for the Net-Zero Grid

Monday, November 13, 2023

• Solar-Powered Device Produces Clean Water and Clean Fuel at the Same Time

Thursday, November 9, 2023

• 'Indoor Solar' To Power the Internet of Things

Friday, November 3, 2023

• Photo Battery Achieves Competitive Voltage

Thursday, November 2, 2023

• Two Million European Households Could Abandon the Electrical Grid by 2050

Wednesday, November 1, 2023

• In a Surprising Finding, Light Can Make Water Evaporate Without Heat

Tuesday, October 31, 2023

• New Database Shines Spotlight on Decades of Solar Mirror Research

Monday, October 30, 2023

• How Robots Can Help Find the Solar Energy of the Future
• The Importance of the Earth's Atmosphere in Creating the Large Storms That Affect Satellite Communications

Friday, October 27, 2023

• 3D Printed Reactor Core Makes Solar Fuel Production More Efficient

Tuesday, October 24, 2023

• Scientists Develop New Method to Create Stable, Efficient Next-Gen Solar Cells

Friday, October 20, 2023

• Pivotal Breakthrough in Adapting Perovskite Solar Cells for Renewable Energy

Tuesday, October 17, 2023

• World May Have Crossed Solar Power 'tipping Point'
• Harnessing Molecular Power: Electricity Generation on the Nanoscale

Monday, October 16, 2023

• Solar Design Would Harness 40% of the Sun's Heat to Produce Clean Hydrogen Fuel

Tuesday, October 10, 2023

• Modular Dam Design Could Accelerate the Adoption of Renewable Energy

Wednesday, September 27, 2023

• How Organic Solar Cells Could Become Significantly More Efficient

Thursday, September 21, 2023

• Predicting the Sustainability of a Future Hydrogen Economy

Wednesday, September 20, 2023

• Efficient Next-Generation Solar Panels on Horizon Following Breakthrough
• Chameleon-Inspired Coating Could Cool and Warm Buildings Through the Seasons
• New Si-Based Photocatalyst Enables Efficient Solar-Driven Hydrogen Production and Biomass Refinery

Monday, September 18, 2023

• Step Change in Upconversion the Key to Clean Water, Green Energy and Futuristic Medicine

Thursday, September 7, 2023

• Scientists Develop New Method to Recover High-Purity Silicon from Expired Solar Panels for Upcycling Into Lithium-Ion Batteries

Wednesday, September 6, 2023

• New Battery Holds Promise for Green Energy
• Researchers Develop Highly Efficient and Stable Photoelectrode for Water Splitting Using Organic Semiconductors

Wednesday, August 30, 2023

• Energy Storage in Molecules

Monday, August 28, 2023

• Researcher Finds Inspiration from Spider Webs and Beetles to Harvest Fresh Water from Thin Air

Tuesday, August 22, 2023

• Improvements in Silicon-Perovskite Tandem Cells That Helped Achieve a Whopping 32.5 Percent Efficiency

Thursday, August 17, 2023

• To Improve Solar and Other Clean Energy Tech, Look Beyond Hardware

Monday, July 31, 2023

• Sun 'umbrella' Tethered to Asteroid Might Help Mitigate Climate Change

Thursday, July 27, 2023

• Solar Batteries: New Material Makes It Possible to Simultaneously Absorb Light and Store Energy

Saturday, July 22, 2023

• Renewable Solar Energy Can Help Purify Water, the Environment

Thursday, July 20, 2023

• Device Makes Hydrogen from Sunlight With Record Efficiency

Tuesday, July 18, 2023

• Bifacial Perovskite Solar Cells Point to Higher Efficiency

Thursday, July 13, 2023

• Improving High-Temperature Stability of Perovskite Solar Cells

Monday, July 10, 2023

• Unused Renewable Energy an Option for Powering NFT Trade

Friday, July 7, 2023

• Organic Electronics: Sustainability During the Entire Lifecycle

Thursday, June 22, 2023

• Perovskite Solar Cells Set New Record for Power Conversion Efficiency

Monday, June 19, 2023

• Clean, Sustainable Fuels Made 'from Thin Air' And Plastic Waste

Monday, June 12, 2023

• New Material Transforms Light, Creating New Possibilities for Sensors

Tuesday, June 6, 2023

• Proposed Design Could Double the Efficiency of Lightweight Solar Cells for Space-Based Applications

Thursday, June 1, 2023

• Record 19.31% Efficiency With Organic Solar Cells

Tuesday, May 30, 2023

• The Next Generation of Solar Energy Collectors Could Be Rocks

Thursday, May 18, 2023

• Driving on Sunshine: Clean, Usable Liquid Fuels Made from Solar Power

Friday, May 5, 2023

• Exciton Fission: One Photon In, Two Electrons out

Thursday, May 4, 2023

• Researchers Develop an Additive to Efficiently Improve the Efficiency and Stability of Perovskite Solar Cells

Monday, April 24, 2023

• Outstanding Performance of Organic Solar Cell Using Tin Oxide

Thursday, April 20, 2023

• One-Step Solution-Coating Method to Advance Perovskite Solar Cell Manufacturing and Commercialization

Wednesday, April 19, 2023

• New Findings Pave the Way for Stable Organic Solar Cells That May Enable Cheap and Renewable Electricity Generation

Tuesday, April 18, 2023

• Next Decade Decisive for PV Growth on the Path to 2050
• Chemists Propose Ultrathin Material for Doubling Solar Cell Efficiency
• Using Machine Learning to Find Reliable and Low-Cost Solar Cells

Monday, April 17, 2023

• A Solar Hydrogen System That Co-Generates Heat and Oxygen

Friday, April 14, 2023

• Microwaves Advance Solar-Cell Production and Recycling

Thursday, April 13, 2023

• Gentle Method Allows for Eco-Friendly Recycling of Solar Cells
• Scientists Create High-Efficiency Sustainable Solar Cells for IoT Devices With AI-Powered Energy Management

Monday, April 10, 2023

• Solar Cells Charging Forward

Friday, March 24, 2023

• More Predictable Renewable Energy Could Lower Costs

Tuesday, March 21, 2023

• Solar Industry Feeling the Heat Over Disposal of 80 Million Panels

Monday, March 20, 2023

• 'Green' Hydrogen: How Photoelectrochemical Water Splitting May Become Competitive

Thursday, March 16, 2023

• Perovskite Solar Cells from the Slot Die Coater -- A Step Towards Industrial Production

Wednesday, March 15, 2023

• Minimizing Electric Vehicles' Impact on the Grid

Monday, February 27, 2023

• Corralling Ions Improves Viability of Next Generation Solar Cells

Tuesday, February 21, 2023

• Nanoparticles Self-Assemble to Harvest Solar Energy

Thursday, February 16, 2023

• Perovskites, a 'dirt Cheap' Alternative to Silicon, Just Got a Lot More Efficient
• Physicists Solve Durability Issue in Next-Generation Solar Cells

Thursday, February 9, 2023

• Research Reveals Thermal Instability of Solar Cells but Offers a Bright Path Forward

Wednesday, February 1, 2023

• Passive Radiative Cooling Can Now Be Controlled Electrically

Tuesday, January 31, 2023

• Thin, Lightweight Layer Provides Radiation Barrier for Perovskites in Space, Protection from Elements on Earth

Friday, January 27, 2023

• Stability of Perovskite Solar Cells Reaches Next Milestone
• Meteorites Reveal Likely Origin of Earth's Volatile Chemicals

Wednesday, January 18, 2023

• Harnessing Solar Energy: New Method Improves Readings of Double-Sided Panels

Friday, January 13, 2023

• The World in Grains of Interstellar Dust
• LATEST NEWS
• Top Science
• Top Physical/Tech
• Top Environment
• Top Society/Education
• Health & Medicine
• Mind & Brain
• Living Well
• Space & Time
• Matter & Energy
• Business & Industry
• Automotive and Transportation
• Consumer Electronics
• Energy and Resources
• Engineering and Construction
• Telecommunications
• Textiles and Clothing
• Biochemistry
• Inorganic Chemistry
• Organic Chemistry
• Thermodynamics
• Electricity
• Energy Technology
• Alternative Fuels
• Energy Policy
• Fossil Fuels
• Nuclear Energy
• Solar Energy
• Wind Energy
• Engineering
• 3-D Printing
• Civil Engineering
• Construction
• Electronics
• Forensic Research
• Materials Science
• Medical Technology
• Microarrays
• Nanotechnology
• Robotics Research
• Spintronics
• Sports Science
• Transportation Science
• Virtual Environment
• Weapons Technology
• Wearable Technology
• Albert Einstein
• Nature of Water
• Quantum Computing
• Quantum Physics
• Computers & Math
• Plants & Animals
• Earth & Climate
• Fossils & Ruins
• Science & Society
• Education & Learning

Strange & Offbeat

• Two Species Interbreeding Created New Butterfly
• Warming Antarctic Deep-Sea and Sea Level Rise
• Octopus Inspires New Suction Mechanism for ...
• Cities Sinking: Urban Populations at Risk
• Puzzle Solved About Ancient Galaxy
• How 3D Printers Can Give Robots a Soft Touch
• Combo of Multiple Health Stressors Harming Bees
• Methane Emission On a Cold Brown Dwarf
• Remarkable Memories of Mountain Chickadees
• Predicting Future Marine Extinctions

Trending Topics

Maintenance work is planned for Wednesday 1st May 2024 from 9:00am to 11:00am (BST).

During this time, the performance of our website may be affected - searches may run slowly and some pages may be temporarily unavailable. If this happens, please try refreshing your web browser or try waiting two to three minutes before trying again.

We apologise for any inconvenience this might cause and thank you for your patience.

Recent progress in the study of integrated solar cell-energy storage systems

* Corresponding authors

a Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, China E-mail: [email protected] , [email protected]

b Reading Academy, Nanjing University of Information Science & Technology, Nanjing, China

c State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, China

As fossil fuels continue to deplete, the development of sustainable and green energy sources has become crucial for human societal advancement. Among the various renewable energies, solar energy stands out as a promising substitute for conventional fossil fuels, offering widespread availability and a pollution-free solution. Solar cells, as devices that convert solar energy, are garnering significant focus. However, the intermittent nature of solar energy results in a high dependence on weather conditions of solar cells. Integrated solar cell-energy storage systems that integrate solar cells and energy storage devices may solve this problem by storing the generated electricity and managing the energy output. This review delves into the latest developments in integrated solar cell-energy storage systems, marrying various solar cells with either supercapacitors or batteries. It highlights their construction, material composition, and performance. Additionally, it discusses prevailing challenges and future possibilities, aiming to spark continued advancement and innovation in the sector.

• This article is part of the themed collection: Recent Review Articles

Article information

Download citation, permissions.

Y. Lu, M. Chen, G. Zhu and Y. Zhang, Nanoscale , 2024, Advance Article , DOI: 10.1039/D4NR00839A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page .

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page .

Read more about how to correctly acknowledge RSC content .

Social activity

Search articles by author.

This article has not yet been cited.

Advertisements

Suggestions or feedback?

MIT News | Massachusetts Institute of Technology

• Machine learning
• Social justice
• Black holes
• Classes and programs

Departments

• Aeronautics and Astronautics
• Brain and Cognitive Sciences
• Architecture
• Political Science
• Mechanical Engineering

Centers, Labs, & Programs

• Abdul Latif Jameel Poverty Action Lab (J-PAL)
• Picower Institute for Learning and Memory
• Lincoln Laboratory
• School of Architecture + Planning
• School of Engineering
• School of Humanities, Arts, and Social Sciences
• Sloan School of Management
• School of Science
• MIT Schwarzman College of Computing

Researchers find benefits of solar photovoltaics outweigh costs

Press contact :.

Previous image Next image

Over the past decade, the cost of solar photovoltaic (PV) arrays has fallen rapidly. But at the same time, the value of PV power has declined in areas that have installed significant PV generating capacity. Operators of utility-scale PV systems have seen electricity prices drop as more PV generators come online. Over the same time period, many coal-fired power plants were required to install emissions-control systems, resulting in declines in air pollution nationally and regionally. The result has been improved public health — but also a decrease in the potential health benefits from offsetting coal generation with PV generation.

Given those competing trends, do the benefits of PV generation outweigh the costs? Answering that question requires balancing the up-front capital costs against the lifetime benefits of a PV system. Determining the former is fairly straightforward. But assessing the latter is challenging because the benefits differ across time and place. “The differences aren’t just due to variation in the amount of sunlight a given location receives throughout the year,” says  Patrick R. Brown PhD ’16, a postdoc at the MIT Energy Initiative. “They’re also due to variability in electricity prices and pollutant emissions.”

The drop in the price paid for utility-scale PV power stems in part from how electricity is bought and sold on wholesale electricity markets. On the “day-ahead” market, generators and customers submit bids specifying how much they’ll sell or buy at various price levels at a given hour on the following day. The lowest-cost generators are chosen first. Since the variable operating cost of PV systems is near zero, they’re almost always chosen, taking the place of the most expensive generator then in the lineup. The price paid to every selected generator is set by the highest-cost operator on the system, so as more PV power comes on, more high-cost generators come off, and the price drops for everyone. As a result, in the middle of the day, when solar is generating the most, prices paid to electricity generators are at their lowest.

Brown notes that some generators may even bid negative prices. “They’re effectively paying consumers to take their power to ensure that they are dispatched,” he explains. For example, inflexible coal and nuclear plants may bid negative prices to avoid frequent shutdown and startup events that would result in extra fuel and maintenance costs. Renewable generators may also bid negative prices to obtain larger subsidies that are rewarded based on production. 

Health benefits also differ over time and place. The health effects of deploying PV power are greater in a heavily populated area that relies on coal power than in a less-populated region that has access to plenty of clean hydropower or wind. And the local health benefits of PV power can be higher when there’s congestion on transmission lines that leaves a region stuck with whatever high-polluting sources are available nearby. The social costs of air pollution are largely “externalized,” that is, they are mostly unaccounted for in electricity markets. But they can be quantified using statistical methods, so health benefits resulting from reduced emissions can be incorporated when assessing the cost-competitiveness of PV generation.

The contribution of fossil-fueled generators to climate change is another externality not accounted for by most electricity markets. Some U.S. markets, particularly in California and the Northeast, have implemented cap-and-trade programs, but the carbon dioxide (CO 2 ) prices in those markets are much lower than estimates of the social cost of CO 2 , and other markets don’t price carbon at all. A full accounting of the benefits of PV power thus requires determining the CO 2  emissions displaced by PV generation and then multiplying that value by a uniform carbon price representing the damage that those emissions would have caused.

Calculating PV costs and benefits

To examine the changing value of solar power, Brown and his colleague Francis M. O’Sullivan, the senior vice president of strategy at Ørsted Onshore North America and a senior lecturer at the MIT Sloan School of Management, developed a methodology to assess the costs and benefits of PV power across the U.S. power grid annually from 2010 to 2017. 

The researchers focused on six “independent system operators” (ISOs) in California, Texas, the Midwest, the Mid-Atlantic, New York, and New England. Each ISO sets electricity prices at hundreds of “pricing nodes” along the transmission network in their region. The researchers performed analyses at more than 10,000 of those pricing nodes.

For each node, they simulated the operation of a utility-scale PV array that tilts to follow the sun throughout the day. They calculated how much electricity it would generate and the benefits that each kilowatt would provide, factoring in energy and “capacity” revenues as well as avoided health and climate change costs associated with the displacement of fossil fuel emissions. (Capacity revenues are paid to generators for being available to deliver electricity at times of peak demand.) They focused on emissions of CO 2 , which contributes to climate change, and of nitrogen oxides (NO x ), sulfur dioxide (SO 2 ), and particulate matter called PM 2.5 — fine particles that can cause serious health problems and can be emitted or formed in the atmosphere from NO x  and SO 2 .

The results of the analysis showed that the wholesale energy value of PV generation varied significantly from place to place, even within the region of a given ISO. For example, in New York City and Long Island, where population density is high and adding transmission lines is difficult, the market value of solar was at times 50 percent higher than across the state as a whole. 

The public health benefits associated with SO 2 , NO x , and PM 2.5  emissions reductions declined over the study period but were still substantial in 2017. Monetizing the health benefits of PV generation in 2017 would add almost 75 percent to energy revenues in the Midwest and New York and fully 100 percent in the Mid-Atlantic, thanks to the large amount of coal generation in the Midwest and Mid-Atlantic and the high population density on the Eastern Seaboard. 

Based on the calculated energy and capacity revenues and health and climate benefits for 2017, the researchers asked: Given that combination of private and public benefits, what upfront PV system cost would be needed to make the PV installation “break even” over its lifetime, assuming that grid conditions in that year persist for the life of the installation? In other words, says Brown, “At what capital cost would an investment in a PV system be paid back in benefits over the lifetime of the array?” 

Assuming 2017 values for energy and capacity market revenues alone, an unsubsidized PV investment at 2017 costs doesn’t break even. Add in the health benefit, and PV breaks even at 30 percent of the pricing nodes modeled. Assuming a carbon price of $50 per ton, the investment breaks even at about 70 percent of the nodes, and with a carbon price of $100 per ton (which is still less than the price estimated to be needed to limit global temperature rise to under 2 degrees Celsius), PV breaks even at all of the modeled nodes. 

That wasn’t the case just two years earlier: At 2015 PV costs, PV would only have broken even in 2017 at about 65 percent of the nodes counting market revenues, health benefits, and a $100 per ton carbon price. “Since 2010, solar has gone from one of the most expensive sources of electricity to one of the cheapest, and it now breaks even across the majority of the U.S. when considering the full slate of values that it provides,” says Brown. 

Based on their findings, the researchers conclude that the decline in PV costs over the studied period outpaced the decline in value, such that in 2017 the market, health, and climate benefits outweighed the cost of PV systems at the majority of locations modeled. “So the amount of solar that’s competitive is still increasing year by year,” says Brown. 

The findings underscore the importance of considering health and climate benefits as well as market revenues. “If you’re going to add another megawatt of PV power, it’s best to put it where it’ll make the most difference, not only in terms of revenues but also health and CO 2 ,” says Brown. 

Unfortunately, today’s policies don’t reward that behavior. Some states do provide renewable energy subsidies for solar investments, but they reward generation equally everywhere. Yet in states such as New York, the public health benefits would have been far higher at some nodes than at others. State-level or regional reward mechanisms could be tailored to reflect such variation in node-to-node benefits of PV generation, providing incentives for installing PV systems where they’ll be most valuable. Providing time-varying price signals (including the cost of emissions) not only to utility-scale generators, but also to residential and commercial electricity generators and customers, would similarly guide PV investment to areas where it provides the most benefit. 

Time-shifting PV output to maximize revenues 

The analysis provides some guidance that might help would-be PV installers maximize their revenues. For example, it identifies certain “hot spots” where PV generation is especially valuable. At some high-electricity-demand nodes along the East Coast, for instance, persistent grid congestion has meant that the projected revenue of a PV generator has been high for more than a decade. The analysis also shows that the sunniest site may not always be the most profitable choice. A PV system in Texas would generate about 20 percent more power than one in the Northeast, yet energy revenues were greater at nodes in the Northeast than in Texas in some of the years analyzed. 

To help potential PV owners maximize their future revenues, Brown and O’Sullivan performed a follow-on study focusing on ways to shift the output of PV arrays to align with times of higher prices on the wholesale market. For this analysis, they considered the value of solar on the day-ahead market and also on the “real-time market,” which dispatches generators to correct for discrepancies between supply and demand. They explored three options for shaping the output of PV generators, with a focus on the California real-time market in 2017, when high PV penetration led to a large reduction in midday prices compared to morning and evening prices.

• Curtailing output when prices are negative: During negative-price hours, a PV operator can simply turn off generation. In California in 2017, curtailment would have increased revenues by 9 percent on the real-time market compared to “must-run” operation.
• Changing the orientation of “fixed-tilt” (stationary) solar panels: The general rule of thumb in the Northern Hemisphere is to orient solar panels toward the south, maximizing production over the year. But peak production then occurs at about noon, when electricity prices in markets with high solar penetration are at their lowest. Pointing panels toward the west moves generation further into the afternoon. On the California real-time market in 2017, optimizing the orientation would have increased revenues by 13 percent, or 20 percent in conjunction with curtailment.
• Using 1-axis tracking: For larger utility-scale installations, solar panels are frequently installed on automatic solar trackers, rotating throughout the day from east in the morning to west in the evening. Using such 1-axis tracking on the California system in 2017 would have increased revenues by 32 percent over a fixed-tilt installation, and using tracking plus curtailment would have increased revenues by 42 percent.

The researchers were surprised to see how much the optimal orientation changed in California over the period of their study. “In 2010, the best orientation for a fixed array was about 10 degrees west of south,” says Brown. “In 2017, it’s about 55 degrees west of south.” That adjustment is due to changes in market prices that accompany significant growth in PV generation — changes that will occur in other regions as they start to ramp up their solar generation.

The researchers stress that conditions are constantly changing on power grids and electricity markets. With that in mind, they made their database and computer code openly available so that others can readily use them to calculate updated estimates of the net benefits of PV power and other distributed energy resources.

They also emphasize the importance of getting time-varying prices to all market participants and of adapting installation and dispatch strategies to changing power system conditions. A law set to take effect in California in 2020 will require all new homes to have solar panels. Installing the usual south-facing panels with uncurtailable output could further saturate the electricity market at times when other PV installations are already generating.

“If new rooftop arrays instead use west-facing panels that can be switched off during negative price times, it’s better for the whole system,” says Brown. “Rather than just adding more solar at times when the price is already low and the electricity mix is already clean, the new PV installations would displace expensive and dirty gas generators in the evening. Enabling that outcome is a win all around.”

Patrick Brown and this research were supported by a U.S. Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) Postdoctoral Research Award through the EERE Solar Energy Technologies Office. The computer code and data repositories are available here and here .

This article appears in the  Spring 2020  issue of  Energy Futures, the magazine of the MIT Energy Initiative. 

Share this news article on:

Related links.

• Paper: “Shaping photovoltaic array output to align with changing wholesale electricity price profiles.”
• Paper: “Spatial and temporal variation in the value of solar power across United States electricity markets.”
• Report: “The Future of Solar Energy”
• Patrick Brown
• MIT Energy Initiative
• Energy Futures magazine

Related Topics

• MIT Sloan School of Management
• Climate change
• Photovoltaics
• Environment
• Sustainability
• Renewable energy

Related Articles

Solar energy farms could offer second life for electric vehicle batteries

For cheaper solar cells, thinner really is better

MITEI releases report on the future of solar energy

Previous item Next item

More MIT News

Featured video: Moooving the needle on methane

Read full story →

The many-body dynamics of cold atoms and cross-country running

Heather Paxson named associate dean for faculty of the School of Humanities, Arts, and Social Sciences

Preparing MIT’s campus for cardiac emergencies

Researching extreme environments

To build a better AI helper, start by modeling the irrational behavior of humans

• More news on MIT News homepage →

Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA, USA

• Map (opens in new window)
• Events (opens in new window)
• People (opens in new window)
• Careers (opens in new window)
• Accessibility
• Social Media Hub
• MIT on Facebook
• MIT on YouTube
• MIT on Instagram

Optimal planning and designing of microgrid systems with hybrid renewable energy technologies for sustainable environment in cities

• Research Article
• Published: 22 April 2024

Cite this article

• Peddakapu Kurukuri 1 ,
• Mohd Rusllim Mohamed   ORCID: orcid.org/0000-0002-9194-0553 2 ,
• Pavan Harika Raavi 3 &
• Yogendra Arya 4  

Although hybrid wind-biomass-battery-solar energy systems have enormous potential to power future cities sustainably, there are still difficulties involved in their optimal planning and designing that prevent their widespread adoption. This article aims to develop an optimal sizing of microgrids by incorporating renewable energy (RE) technologies for improving cost efficiency and sustainability in urban areas. Diverse RE technologies such as photovoltaic (PV) systems, biomass, batteries, wind turbines, and converters are considered for system configuration to obtain this goal. Net present cost ( NPC ) is this study’s objective function for optimal sizing microgrid configuration. For demonstration, we assess the technical, economic factors, and atmospheric emissions of optimal hybrid renewable energy systems for Putrajaya City in Malaysia. The required solar radiation data, temperature, and wind speeds are collected from the NASA surface metrological database. From the quantitative analysis of simulations, the biomass-battery-based system has optimal economic outcomes compared to other systems with an NPC of around 1.07 M$, while the cost of energy ( COE ) is 0.118 $/kWh. Moreover, environmentally safe nitrogen oxide emissions, carbon monoxide, and carbon dioxide concentrations exist. The grid-tied RE technology boasts cost-effectiveness, with an NPC of 348,318 $ and a COE of 0.0112 $/kWh. This study aids decision-makers in formulating policies for integrating hybrid RE systems in urban areas, promoting sustainable energy generation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Data Availability

The datasets can be avaliable based on reasonable request.

Aberilla JM, Gallego-Schmid A, Stamford L, Azapagic A (2020) Design and environmental sustainability assessment of small-scale off-grid energy systems for remote rural communities. Appl Energy 258:114004

Article   Google Scholar  

Ahmadi SE et al (2022) Decentralized bi-level stochastic optimization approach for multi-agent multi-energy networked micro-grids with multi-energy storage technologies. Energy 245:123223

Akarsu B, Genç MS (2022) Optimization of electricity and hydrogen production with hybrid renewable energy systems. Fuel 324:124465

Article   CAS   Google Scholar  

Apata O, Oyedokun DTO (2020) An overview of control techniques for wind turbine systems. Sci Afr 10:e00566

Google Scholar  

Bagheri M, Shirzadi N, Bazdar E, Kennedy CA (2018) Optimal planning of hybrid renewable energy infrastructure for urban sustainability: green Vancouver. Renew Sustain Energy Rev 95:254–264

Bhuyan M, Dulal CD, Amar KB, Subash CS (2022) Performance assessment of novel solar thermal-based dual hybrid microgrid system using CBOA optimized cascaded PI-Tid controller. IETE J Res 1–18

Blasi S, Ganzaroli A, De Noni I (2022) Smartening sustainable development in cities: strengthening the theoretical linkage between smart cities and SDGs. Sustain Cities Soc 80:103793

Bouendeu JJ et al (2023) A systematic techno-enviro-socio-economic design optimization and power quality of hybrid renewable microgrids. Renew Energy 218:119297

Bui VG et al (2022) Optimizing operation parameters of a spark-ignition engine fueled with biogas-hydrogen blend integrated into biomass-solar hybrid renewable energy system. Energy 252:124052

Dinesh P, Sawle Y (2022) Optimization of hybrid solar, wind, and diesel energy system from cost analysis of micro-grid using Homer software. In: Emerging electronics and automation: select proceedings of E2A 2021. Springer, pp 161–172

Elnozahy A et al (2021) Optimal economic and environmental indices for hybrid PV/wind-based battery storage system. J Electr Eng Technol 16(6):2847–2862

Hong Y-Y, Lian R-C (2012) Optimal sizing of hybrid wind/PV/diesel generation in a stand-alone power system using Markov-based genetic algorithm. IEEE Trans Power Delivery 27(2):640–647

Hugo G (2019) Internal migration, urbanization and poverty in Asia: dynamics and interrelationships. Patterns and trends of urbanization and urban growth in Asia. Springer Singapore

Iqbal R et al (2024) Comparative study based on techno-economics analysis of different shipboard microgrid systems comprising PV/wind/fuel cell/battery/diesel generator with two battery technologies: a step toward green maritime transportation. Renew Energy 221:119670

Jalilian F et al (2022) Multi-energy microgrids: an optimal despatch model for water-energy nexus. Sustain Cities Soc 77:103573

Kazmi SA, Abbas SM, Anwar M (2024) An integrated assessment framework of renewable based microgrid deployment for remote isolated area electrification across different climatic zones and future grid extensions. Sustain Cities Soc 101:105069

Kishore JK, Dokala MR, Mohamed KS, Peddakapu K (2022) Grey wolf optimization and differential evolution-based maximum power point tracking controller for photovoltaic systems under partial shading conditions. Energy Sources, Part a: Recover, Utilization, Environ Eff 44(3):6286–6302

Krishna Kishore DJ, Mohamed MR, Jewaliddin SK, Peddakapu K, Srinivasarao P (2022) Cost regulation and power quality enhancement for PV-wind-battery system using grasshopper optimisation approach. Int J Ambient Energy 1–12

Kumar P, Pal N, Sharma H (2022) Optimization and techno-economic analysis of a solar photo-voltaic/biomass/diesel/battery hybrid off-grid power generation system for rural remote electrification in Eastern India. Energy 247:123560

Li J, Liu P, Li Z (2022) Optimal design and techno-economic analysis of a hybrid renewable energy system for off-grid power supply and hydrogen production: a case study of West China. Chem Eng Res Des 177:604–614

Manas M, Shivi Sharma K, Reddy S, Srivastava A (2023) A critical review on techno-economic analysis of hybrid renewable energy resources-based microgrids. J Eng Appl Sci 70(1):148

Marocco P, Ferrero D, Lanzini A, Santarelli M (2022) The role of hydrogen in the optimal design of off-grid hybrid renewable energy systems. J Energy Storage 46:103893

Mosadeghy M, Yan R, Saha TK (2015) A time-dependent approach to evaluate capacity value of wind and solar PV generation. IEEE Trans Sustain Energy 7(1):129–138

Moser S (2010) Putrajaya: Malaysia’s new federal administrative capital. Cities 27(4):285–297

Muna YB, Kuo C-C (2022) Feasibility and techno-economic analysis of electric vehicle charging of PV/wind/diesel/battery hybrid energy system with different battery technology. Energies 15(12):4364

Mustafa KM, Ashraf I (2023) Evaluation of a hybrid power system based on renewable and energy storage for reliable rural electrification. Renew Energy Focus 45:179–191

Naderipour A et al (2022) Hybrid energy system optimization with battery storage for remote area application considering loss of energy probability and economic analysis. Energy 239:122303

Nathaniel SP, Yalçiner K, Bekun FV (2021) Assessing the environmental sustainability corridor: linking natural resources, renewable energy, human capital, and ecological footprint in BRICS. Resour Policy 70:101924

Odetoye OA et al (2023) Multi-year techno-economic assessment of proposed zero-emission hybrid community microgrid in Nigeria using HOMER. Heliyon 9:9

Owolabi AB et al (2019) Validating the techno-economic and environmental sustainability of solar PV technology in Nigeria using RETScreen experts to assess its viability. Sustain Energy Technol Assess 36:100542

Peddakapu K et al (2020) Performance analysis of distributed power flow controller with ultra-capacitor for regulating the frequency deviations in restructured power system. J Energy Storage 31:101676

Peddakapu K et al (2022) A state-of-the-art review on modern and future developments of AGC/LFC of conventional and renewable energy-based power systems. Renew Energy Focus 43:146–171

Saiprasad N, Kalam A, Zayegh A (2019) Triple bottom line analysis and optimum sizing of renewable energy using improved hybrid optimization employing the genetic algorithm: a case study from India. Energies 12(3):349

Sarwar Md, Warsi NA, Siddiqui AS, Kirmani S (2022) Optimal selection of renewable energy-based microgrid for sustainable energy supply. Int J Energy Res 46(5):5828–5846

Sharma PK et al (2023) Energy storage system based on hybrid wind and photovoltaic technologies. Meas Sensors 30:100915

Shufian A, Hoque M-A-M, Kabir S, Mohammad N (2022) Optimized performance and economic assessment for hybrid island microgrid system considering uncertainties. Technol Econ Smart Grids Sustain Energy 7(1):32

Singh SS, Fernandez E (2018) Modeling, size optimization and sensitivity analysis of a remote hybrid renewable energy system. Energy 143:719–731

Srinivasarao P et al (2021) Simulation and experimental design of adaptive-based maximum power point tracking methods for photovoltaic systems. Comput Electr Eng 89:106910

Teh JS et al (2021) The potential of sustainable biomass producer gas as a waste-to-energy alternative in Malaysia. Sustainability 13(7):3877

TNB (2014) Tenaga Nasional Berhad electricity tariff schedule. https://www.tnb.com.my/residential/pricing-tariffs

Tomin N, Shakirov V, Kurbatsky V et al (2022a) A multi-criteria approach to designing and managing a renewable energy community. Renew Energy 199:1153–1175

Tomin N, Shakirov V, Kozlov A et al (2022b) Design and optimal energy management of community microgrids with flexible renewable energy sources. Renew Energy 183:903–921

Tremblay O, Dessaint L-A (2009) Experimental validation of a battery dynamic model for EV applications. World Electr Veh J 3(2):289–298

U.S. Energy Information Administration (2018) A guide to EIA electric power data. https://www.eia.gov/electricity/data/guide/pdf/guide.pdf

Uddin M, Mo H, Dong D, Elsawah S (2023) Techno-economic potential of multi-energy community microgrid: the perspective of Australia. Renew Energy 219:119544

Vendoti S, Muralidhar M, Kiranmayi R (2021) Techno-economic analysis of off-grid solar/wind/biogas/biomass/fuel cell/battery system for electrification in a cluster of villages by HOMER software. Environ Dev Sustain 23(1):351–372

Download references

The current research is funded by Universiti Malaysia Pahang Al-Sultan Abdullah (UMPSA) under grant number PGRS200322. The Center for Advanced Industrial Technology at UMPSA granted a postdoctoral research fellowship to Peddakapu Kurukuri.

Author information

Authors and affiliations.

Centre for Advanced Industrial Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, Pekan, Malaysia

Peddakapu Kurukuri

Faculty of Electrical & Electronics Engineering Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, Pekan, Malaysia

Mohd Rusllim Mohamed

Centre for Climate Research Singapore (CCRS), Singapore, Singapore

Pavan Harika Raavi

Department of Electrical Engineering, J.C. Bose University of Science & Technology, YMCA, Faridabad, India

Yogendra Arya

You can also search for this author in PubMed   Google Scholar

Contributions

Peddakapu Kurukuri: conceiving and designing the study, collecting data, composing the manuscript, analyzing and/or interpreting the data, revising the manuscript, and approving the final version for publication.

Mohd Rusllim Mohamed: conceiving and designing the study, analyzing and/or interpreting the data, critically revising the manuscript for significant intellectual content, and approving the version of the manuscript to be published.

Pavan Harika Raavi: analyzing and/or interpreting data, critically revising the manuscript for important intellectual content, and approving the version of the manuscript for publication.

Yogendra Arya: drafting the manuscript, revising the manuscript, and approving the final version for publication.

Corresponding author

Correspondence to Mohd Rusllim Mohamed .

Ethics declarations

Ethical approval.

This manuscript does not contain the studies with human participants or animals performed by any of the others.

Consent of participate

Not applicable.

Consent for publication

Conflict of interest.

The authors declare no competing interests.

Additional information

Responsible Editor: Philippe Garrigues

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Kurukuri, P., Mohamed, M.R., Raavi, P.H. et al. Optimal planning and designing of microgrid systems with hybrid renewable energy technologies for sustainable environment in cities. Environ Sci Pollut Res (2024). https://doi.org/10.1007/s11356-024-33254-5

Download citation

Received : 05 July 2023

Accepted : 04 April 2024

Published : 22 April 2024

DOI : https://doi.org/10.1007/s11356-024-33254-5

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Carbon emissions
• Renewable energy sources
• Find a journal
• Publish with us
• Track your research

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.45(Suppl 1); 2016 Jan

Solar energy for electricity and fuels

Olle inganäs.

Biomolecular and Organic Electronics, IFM, Linköpings Universitet, 58183 Linköping, Sweden

Villy Sundström

Chemical Physics, Lund University, P.O. Box 124, 22100 Lund, Sweden

Solar energy conversion into electricity by photovoltaic modules is now a mature technology. We discuss the need for materials and device developments using conventional silicon and other materials, pointing to the need to use scalable materials and to reduce the energy payback time. Storage of solar energy can be achieved using the energy of light to produce a fuel. We discuss how this can be achieved in a direct process mimicking the photosynthetic processes, using synthetic organic, inorganic, or hybrid materials for light collection and catalysis. We also briefly discuss challenges and needs for large-scale implementation of direct solar fuel technologies.

Introduction

Renewable energies are still dominated by bio-energy and hydro-energy. This technology is well developed and more energy can be produced but are inherently limited (Fig.  1 ). Vegetation exists on some 80 million km 2 with an average net bio-energy production of around 0.1 W/m 2 . Higher production would require active nitrogen. Hydro-energy is even more limited.

A comparison of finite and renewable planetary energy reserves measured in TW/years. Total recoverable reserves are shown in TWy for the finite resources, and yearly potential for the renewables. OTEC = Ocean thermal energy conversion. One TWy is 8760 TWh. This figure does not include shale gas or shale oil nor the energy available in methane hydrate. Source: Perez and Perez ( 2009 )

Photovoltaic electricity from solar cells has undergone a rapid development and is rapidly being used both in minor private systems as well as in large-scale installations connected to the national grids. Wind energy has also reach maturity and undergoes presently a rapid worldwide implementation. The main challenge with the renewable energy is the intermittency requiring major storage or large-scale integration.

This article focuses on solar energy, identifying the need for breakthroughs in more efficient ways to produce (i) electricity from more powerful and cost efficient solar cells (ii) the possibility of direct conversion of solar energy into fluid (such as ethanol or methanol) or gas forms (methane of hydrogen), and (iii) the need for producing significantly higher bioconversion including breeding of special plants and genetic engineering of cyanobacteria.

The annual flow of energy from the sun dwarfs all other non-renewable energy flows and stocks, and is several orders of magnitude above what humankind needs (Fig.  1 ). Very major secondary flows of solar energy are concentrated by the thermal engine of the atmosphere, supplying flow of water for hydropower, and flow of air for wind power. From inside the Earth, geothermal heat is delivered from nuclear processes. All these are very small by comparison to the solar influx. The solar influx over land on a horizontal surface varies considerably between different regions and with the diurnal and annual cycle. The most favorable areas are in the subtropics where values can reach almost 300 W/m 2 in annual average, while in parts of northern Europe values can be as low as around 50 W/m 2 with very low values during winter. The diurnal variation of the solar energy influx matches somewhat but not perfectly the activity patterns of societies. There is therefore a great need to store solar derived energy as electrical or chemical energy, to be used at some later time.

Photovoltaic

Current scientific status.

Photovoltaic devices generate electrical power upon illumination (Fig.  2 ). The electrical current is generated as photons from sunlight are absorbed and charges are generated in a semiconductor material. Semiconductors such as silicon absorb a large fraction of sunlight, but below the absorption edge (band gap) of the semiconductor, no absorption occurs. This controls the photocurrent and thus the electrical power of the devices, in combination with the voltage which is influenced by very basic physics and materials science parameters.

a The solar radiation arriving at the surface of the earth is distributed over different wavelengths of light, with tails extending far out in the infrared and invisible region. With semiconductor materials, light with energy higher/wavelengths shorter than the band gap of the material can be absorbed (shadow in graph), but none below the band gap. b The semiconductor is contacted with electrodes and exposed to solar light. Photocurrent J sc from the devices depends on absorption and charge generation in the active material; the photo-voltage V oc basically depends on the materials. c The current–voltage curve shows both these parameters, and the device is used to deliver electricity at the maximum power delivery point, indicated with a star

The science of photovoltaic is a mature field. Novel photovoltaic materials arrive, and scientists later learn how to accommodate these novel phenomena to the scientific terminology of photovoltaics. The thermodynamic limitations analyzed by Shockley and Queisser (S–Q) in ( 1961 ) resulted in a maximum efficiency of slightly over 33 % in a single-junction device using a band gap of 1.1–1.4 eV. These limitations are due to heat losses from high energy photons above the single-band gap, and from loss of photons not absorbed below the band gap. It is also based on the equilibrium flux of photons to the photovoltaic device from the sun, and the flow of photons to the universe from the photovoltaic device. This is a description that is valid for well established materials, like crystalline and poly-crystalline silicon-based photovoltaic, but also for amorphous inorganic semiconductors in thin film format, as well as newer organics in wet or dry state conditions, and new hybrid organic–inorganic materials. Though the science is mature, the implications of this science have not always been fully acknowledged. The recent improvement, to 28.8 % power conversion efficiency (PCE), of high performance gallium arsenide (GaAs) single-junction solar cells, has been accomplished by photonic engineering, to manipulate the balance between the incoming and outgoing photon flux, with the reward coming as voltage from the cell (Miller et al. 2012 ).

Improved energy conversion is found in multi-junction solar cells, or tandem solar cells, where the heat and transmission losses are minimized by use of two, three, or more different materials of different band gaps, and connecting these devices in electrical series. These are very high performance solar cells, with power conversion efficiencies up to 44.7 % under the direct sun spectrum at very high concentrations. These solar cells are mostly used in space, or under concentrated solar light on earth. The delicate growth of several compound semiconductors on top of each other to create these structures results in a higher material and processing cost. Therefore, these solar cells are mostly relevant together with concentrating optical elements, and thus require high performance, low-cost concentrators, which only work well in direct sunlight. Such concentrator systems are today becoming more widely available and applications in the multi MW range have been realized.

Attempts to use the part of the solar spectrum found in the infrared and far infrared, carrying 50 % of the solar energy, for photovoltaic energy conversion is of relevance, in particular in combination with tandems. For single-band gap devices, the optimum band gap is 1.1–1.4 eV, and the lower energy part of the solar spectrum is sacrificed.

Current technological developments

Developments of silicon photovoltaic markets and technology.

The goal of 0.4 €/W p for photovoltaic (PV) modules is close to appear in the silicon photovoltaic market, where the wholesale price is now 0.5 €/W p , and where the financial difficulties of most companies indicates that variable costs in their production are c. 0.4 €/W p . The dramatic reductions of silicon PV sales prices (to 20 % during the last 5 years) are mainly due to market pressure resulting from oversupply, increased production volumes leading to cost reduction by scale, and to some degree also due to technological advancement. Extrapolating that pace of technological improvement in the near future, short-term market and technology analysis indicate that by year 2017 the production cost of 0.3 €/W p will be reached. The learning curve of silicon PV may, however, decelerate as sales prices go so low that new technology cannot be acquired and financed, or by reaching the technology limits given by the requirement for crystalline layers with – due to the indirect band gap of silicon—large thickness.

However, already today photovoltaic electricity generation cost can be as low as 12 €cents/KWh in countries like France or Germany and 8 €cents/KWh in the south of Europe. Within the next decade solar electricity from photovoltaics is likely to become the cheapest form of renewable energy in most parts of the world. Silicon is an established photovoltaic material, it is widely available, non-toxic and it is likely to dominate the market for the foreseeable future. However, production cost of electricity is not the only element, as the electricity system cost represents typically 40–60 % of the final cost.

This major cost reduction of silicon PV puts significant pressure on all alternative technologies like thin film inorganic photovoltaics (e.g., a-Si, CdTe, CIGS) which lost in market share during recent years, but improved somewhat in record performance numbers. All PV technologies in the future will have to approach higher conversion efficiencies to reduce the contribution of all other module components. Whether there is a place for low efficiency, low-cost solar cells to compete with silicon photovoltaic is now more doubtful than 5 years back, as the cost of silicon has dropped.

The combination of silicon PV with compound semiconductors (thin film III-V compounds or nanowires) in hybrid tandem photovoltaic promises big improvements of power conversion efficiencies, and may be one of the most attractive pathways for rapid improvement in PCE. Also these approaches can benefit from the advances in silicon photovoltaic like lower material costs and enhanced manufacturing technologies.

Hybrid organic/inorganic solar cells

High performance dye sensitized solar cells, where an organic compound in contact with a high band gap inorganic semiconductor (e.g., TiO 2 , ZnO, ZrO 2 ) generates charge upon photon absorption, still require a redox liquid electrolyte for best performance. Alternative redox design using cobalt compounds has improved efficiencies to 13 %. Solid state versions of the dye sensitized solar cells have lower PCE. A new inorganic absorber, a perovskite based on lead halogen compound first used for dye sensitized solar cells, has rapidly demonstrated that this compound can be used at its best (18 % power conversion efficiency) in thin film geometries (Jeon Jeon et al. 2015 ), as optical absorption and electronic transport is sufficient in this material; the advantages of the dye sensitized cells are thereby removed for this absorber.

Solid state organic solar cells

Development of organic donor/acceptor-based photovoltaic (OPV), where donor and acceptor are typically organic molecules or polymers, is accelerating, with best efficiencies now at 12 % (Heliatek 2012 ; Mitsubishi 2013 ). The photo-voltage from these materials is controlled by a charge transfer state generated at the interface between the donor/acceptor (Vandewal et al. 2009 ). Though the basic physics of these photovoltaic materials is now somewhat mature, there is still a large room for improvement by chemical design. With improvement of 1 % unit per year, and limits to PCE still above 20 %, there is reason to expect 15–20 % PCE as an outcome of novel materials.

As the active materials in OPVs are carbon based, these are generally very scalable materials. The production methods for OPV include printing from solvents or evaporation of molecules through vacuum. Both are amenable for large area deposition, with somewhat different potential speed of production and capital costs of equipment. Printing is the faster and cheaper, and rapidly scalable to produce large areas of photovoltaic modules on the global scale.

For both OPV and dye sensitized cells, they operate well under low lights, high temperatures and considerably improve the light harvesting compared to silicon devices. The extra yield of almost a 1/3 from an organic-based module will give the same amount of kWh from a 15 % organic module as compared to a 20 % silicon module.

In the comparison of early organic photovoltaic systems, which have no market share yet, issues of lifetime and module efficiency are largely unresolved. Whether they will be sufficient to compete with mature silicon photovoltaic is not clear, and they will most probably not enter into power plants but rather be used in building integration.

Needs for breakthroughs

Scalability of semiconductor materials.

Silicon- or carbon-based materials, which can be scaled up, deliver 25 % (Si) and 12–13 % (carbon based) power conversion efficiency in best lab devices. Several of the competing thin film technologies suffer from a dependence on rare or toxic materials which reduces their potential to play a significant role when photovoltaics will be used in large-scale systems. Therefore, the use of earth abundant materials or efficient recycling concepts will be important for large-scale deployment of the technologies. Removing materials limitations due to less abundant elements (for active materials e.g., indium, gallium, tellurium, for current collectors silver) by substitution with more abundant elements (e.g., zinc, sulfur or copper, aluminum) will be a general and critical target.

Decreasing the energy payback time of solar cells

Measures and means needed

• Reducing the energy input in photovoltaic modules production. Low-temperature processes, substrates with low embodied energy, repeated use of substrates for growth of high quality materials/devices, closure of the materials cycle during the life cycle of devices;
• Extending the technical lifetime of high performance photovoltaic by improved encapsulation and protection.

Materials design

• Designing the electronic properties of carbon-based materials by understanding and controlling the path from single molecular structures via nano-morphology to film growth. A prime example is bulk heterojunctions in organic solid state solar cells which need a nanometer control of morphology in the key active layer.

Areas where scientific and materials breakthroughs may be possible and of potential importance

• Multiple-band gap tandem solar cells incorporating scalable materials;
• Light concentration through far field optics for multiple-band gap materials;
• Nanophotonics in dielectrics and semiconductors for light-matter coupling, light trapping/ light management;
• Plasmonics for light-matter coupling, to direct energy to the semiconductor structure in photovoltaic devices;
• Combination with solar fuel generation, e.g., hydrogen generation by photovoltaic layers with catalyst electrodes.

Identification of research needs of the coming decades

Nanophotonic strategies for light trapping in thin structures.

The well established Yablonovitch limit for light trapping in the limit of geometrical optics is not relevant when arriving at thin film structures that must be analyzed with the wave optics approach. This goes for thin film devices with extremely thin absorbers, and new strategies for optical compression of solar light into such thin absorbers have been proposed. Considerable experimental developments are necessary to exploit such strategies, shaping, and integrating thin film absorbers in a benign optical environment.

Transparent electrode materials, not relying on elements of low abundance

• Carbon based or abundant metal oxide transparent conductors for electrodes;
• New combinations of device/module assembly to generate lower currents and higher voltages for decrease of losses in photovoltaic modules.

Beyond S–Q limits?

The perennial quest for ways of moving beyond the Shockley–Queisser limits for single- and multiple-band gap absorbers in photovoltaic devices may require new approaches for generating electricity. When developing hybrid approaches based on high performance semiconductors, the added energy conversion with novel materials and structures may include up-conversion. Without a band gap alternative physical mechanisms must be found. Current developments in thermoelectrics points to new combinations of photovoltaics and thermoelectrics; optical antennas and rectennas show interesting avenues for creating absorbing structures somewhere between geometric antennas and molecular/elemental semiconductors with defined band gaps.

Solar fuels: Artificial photosynthesis

Direct conversion of solar energy into a fuel mimicking the catalytic processes of photosynthesis would be a way to solve the problem of storing solar energy. A direct process would minimize the number of steps needed from light to fuel, and therefore potentially allow for high conversion efficiencies. The raw material for the (storage) fuel is an important key aspect for the solar fuels. The desirable raw material must be essentially inexhaustible, cheap, and widely available. Most scientists target water as the raw material. Processes in which water is split (oxidized) into its constituents by solar energy can become large contributors to shift away from fossil fuels on a global scale.

The target fuel is another important issue. Many scientists target hydrogen as the solar fuel. When water is used as starting material this is natural for scientific reasons. However, the transition to a hydrogen-based economy is not easy. The hydrogen technologies have their own hurdles to overcome and technological issues to tackle before hydrogen can become a worldwide spread fuel. An alternative is to use CO 2 itself as a second raw material (together with water) to create a carbon-based solar fuel. This might have lower technological problems on a shorter term but will not remove CO 2 from the energy cycle (see Fig.  1 ). In addition, some of the science involved in developing methods for fuel production is most likely more difficult than for hydrogen production.

The envisaged key components of an assembly for production of a solar fuel (H 2 ) using water as raw material are illustrated in Fig.  3 (Hammarström and Hammes-Schiffer 2009 ; Cogdell et al. 2013 ). A photo-sensitizer (PS) absorbs the light from the sun and delivers energized electrons to the proton reducing catalysts (PRC) that generates the fuel, H 2 . The electrons delivered by the sensitizer are replenished by oxidizing (splitting) water with the help of a water splitting catalyst (WSC). In an operating device the WSC and PRC functions would most likely be driven by different sensitizers and physically separated and located on different photo-electrodes in contact with water.

Schematic picture of an artificial photosynthesis assembly consisting of a light collecting photosensitizer (PS), a proton reducing catalyst (PRC), and a water splitting catalyst (WSC)

Predicted power conversion efficiencies: Direct processes for solar fuel

Today, no complete device for (direct) solar fuel generation exists, but sensitizers and catalysts that perform the individual reactions have been developed. Nevertheless, a maximum theoretical Shockley–Queisser (S–Q) efficiency of ~30 % for (direct) solar fuel generation (hydrogen and oxygen from water) can be estimated for a single-band gap sensitized process and assuming a realistic value (~0.15 V) for the over-potential (Hanna and Nozik 2006 ; Blankenship et al. 2011 ). It is foreseeable that the time curve for the development of solar fuel generation devices, with respect both to efficiency and cost, will be faster than for the different PV technologies, because the development to some extent will benefit from progress already made in neighboring fields. The most important being the scientific level in light management, electron and proton transfer, material and nano-science, biochemical, and natural photosynthesis. Technological advances in characterization methods, such as time resolved spectroscopy of many kinds, synchrotrons and new laser techniques, are also vital. Sensitizers and catalysts available today frequently contain elements that are scarce, expensive, or toxic. For large-scale commercial implementation of solar fuels produced by artificial photosynthesis technologies materials based on abundant and environmentally benign elements have to be developed, which most likely will take an additional 10 years or more. This restriction is analogous to PV technology limitations.

In comparison, for solar fuel generation relying on a combination of PV and electrolysis, the thermodynamic limits are given by the S–Q treatment in combination with conditions for electrolysis. For the case of photoelectrolysis, with production of H 2 and O 2 , the over potentials for oxidation of water to oxygen and reduction of protons to hydrogen must be added to the thermodynamic potential of 1.23 V for dissociation. Driven by solar cells, this requires more than one cell, added in series, to generate sufficient voltage for electrolysis. With electrolysis having a quantum efficiency of 80–90 %, and a single-band gap cell of 33 % power conversion efficiency, the maximum efficiency from photon to hydrogen may be limited to ≈30 %. The “artificial leaf” construction of Nocera ( 2012 ), comprising a triple junction amorphous silicon photovoltaic cell interfaced with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt_phosphate cluster (Co-OEC), respectively, is an example of where this technology stands today. The reported overall efficiency of this device is 2.5 %.

Methods to produce direct solar fuels

At present there is no direct process that works on any technological scale. The large potential in the direct processes make them nevertheless attractive future technologies and their development is expected to be require heavy research initiatives in several fields.

As mentioned above and illustrated in Fig.  3 , the key steps for direct solar fuel production mimicking photosynthesis are two catalytic reactions, oxidation of water and reduction of a substrate to produce the fuel. If the substrate is protons a relatively well established catalytic process yields the hydrogen fuel. A carbon-based fuel, for example, an alcohol, might be easier to use, but is probably more difficult to make since it would involve less established catalytic processes. A highly critical aspect is that the catalysts should be made from earth abundant metals like cobalt, manganese, iron and nickel, while scarce elements like iridium, indium, palladium, platinum, rhenium, and ruthenium are not available in amounts large enough to allow development of processes and materials of a scale sufficient to replace fossil fuels.

Molecular and semiconductor nanostructure processes. The light-driven catalyst can be molecular (Hammarström and Hammes-Schiffer 2009 ; Sundström 2009 ; Nocera and Guldi 2009 ; Kamat and Bisquert 2013 ) or non-molecular (Cook et al. 2010 ; Poddutoori et al. 2011 ; Vagnini et al. 2013 ; Joya et al. 2013 ). The physical limitations are equal and the scientific problems are of equal magnitude. The development of catalysts that can assist the light-driven oxidation of water is the main research problem. The capture of solar energy and the formation of hydrogen are easier to achieve. Systems combining the two reactions (light-driven water oxidation and hydrogen formation) have the highest potential with respect to solar energy to fuel conversion of all systems envisioned today (Fig.  3 ).

The catalysts and maybe the entire system for artificial photosynthesis can be entirely molecular in nature. They can thereby be varied through small, deliberate synthetic modifications to improve and fine-tune their properties. They are also amenable to studies with high-level molecular or kinetic spectroscopy. Thereby, the catalytic process can be followed and understood to a very detailed level. A special angle to this research involves biomimetic approaches. Here, knowledge and chemical principles from extremely efficient enzymes are applied in entirely synthetic systems for artificial photosynthesis. A successful scientific example involves the development of di-iron catalysts for the reduction of protons to hydrogen. These are designed from deep knowledge about the structure and function of so called hydrogenase enzymes and there are recent examples of very efficient catalysts in the category (Tamagnini et al. 2007 ). Another example involves mimics of the natural photosynthetic reaction centres, with both catalysis and light harvesting in future artificial photosynthesis devices (Magnuson et al. 2009 ).

In non-molecular systems the light-driven catalysis occurs on metal surfaces, semiconductors or nanostructured carbon-based materials while the catalysts involved for water splitting are often cores of metal oxides, sometimes doped with other metals. A severe limitation is that systems many times are based on catalysts made from scarce and expensive metals. Another disadvantage when compared to the molecular systems is that it is much more difficult to study the mechanism for the reactions involved. An important advantage is that many non-molecular systems are seemingly sturdier against degradation and inactivation while most molecular systems studied to date are unstable and easily break during illumination. It is not obvious that this situation will always prevail when more functional systems have been better characterized. An analogy is the Grätzel cell where the individual parts are fairly unstable but the integrated system is very stable.

A rapid development involves ideas where molecular and non-molecular systems are mixed. They are sometimes known as hybrid systems and the science is very broad and collaborative, involving several scientific fields. Here, the solar energy capture system is semiconductor based or made from some other nanotechnology while the chemistry is carried out by linked molecular catalysts. These catalysts are then made from abundant materials like cobalt, iron, manganese, or nickel similar to the “purely” molecular systems described above. Often catalysis is driven by light via incorporation of a photo-sensitizer between the semiconductor and the catalyst. It is not unlikely that these mixed hybrid systems will become dominant in research and maybe technology since they combine advantages from both fields.

Thermochemical cycles. A totally different technology is the employment of thermal processes (Pagliaro et al. 2010 ) for solar fuels production, which involve generation of very high temperatures in closed environments to split water into its constituents directly. This results in a solar fuel when the high temperature is achieved in a reaction vessel in a solar tower by concentration of solar energy in a heliostat. The technology represents interesting engineering and physical science and is very demanding technically involving very high temperatures and huge systems like heliostats. They are mainly suitable to very sunny locations.

Direct solar fuel needs for breakthroughs

Efficient photo-sensitizers and photocatalysts.

For large-scale implementation of direct solar fuel technologies, water will necessarily be the ultimate electron source for reducing the fuel-producing substrate, protons, CO 2 , etc. New and highly efficient catalysts for water oxidation and fuel generation are urgently needed, as well as sensitizers based on abundant elements:

• Photo-sensitizers frequently contain noble metals (ruthenium), which have to be replaced with cheap and abundant elements. Iron is one example but dyes based on Fe and similar transition metals have unfavorable properties for solar energy conversion, necessitating scientific breakthroughs. At the same time fully organic dyes are appearing. Thus, it can be expected that sensitizers suitable for most applications and for large-scale implementation are likely to appear in not too distant future.
• To achieve highly efficient catalysts for water oxidation and hydrogen (liquid fuel) generation is a considerably more difficult and complex problem. Catalysts may be either molecular complex or solid state (e.g., metal oxide) based. Understanding the mechanisms of O-O and H-H bond formation is key to the development of efficient catalysts. Most of today’s catalysts have low efficiencies and are frequently based on scarce or noble metals, making them unsuitable for large-scale commercial implementation. Here, scientific breakthroughs are needed, both concerning efficiency and developing new catalysts based on abundant and cheap elements. Proof-of-concept catalysts with high efficiencies, based on metals like ruthenium, are likely to appear within the next 10 years, but catalysts suitable for commercial applications most likely will take considerably more time.

Liquid fuels

Liquid solar fuels would facilitate the use of existing infrastructure for the utilization of the fuel. By combining the protons and electrons released as a result of water oxidation with CO 2 in a catalytic process, alcohols or other liquid fuels could be synthesized. This is a scientifically challenging task and there are today no good catalysts for CO 2 reduction. Another problem is that the concentration of CO 2 in the atmosphere is low, necessitating an energy-consuming concentration step, or coupling of the solar fuel production to CO 2 -emissions from e.g., a fossil-fuel power plant or a CCS plant (see MacElroy 2016).

Functional devices for direct solar fuel production

No complete device for (direct) solar fuel production exists. New concepts to assemble sensitizers and catalysts into a functional device producing a fuel through light-driven water splitting have to be developed. One possibility that is considered within the field is to attach sensitizer-catalyst assemblies to a nanostructured electrode surface and placing these electrodes in separate compartments, one for fuel (hydrogen) generation and the other for oxygen evolution. Here, suitable electrode systems have to be developed—methods for sensitizer-catalyst assembly attachment to the electrode must be developed, and electrochemical properties of catalysts and electrode materials matched. Considering that this development is still in its scientific infancy, it will probably take more than 10 years until efficient proof-of-concept systems have been developed and considerably more time until commercially suitable devices are available.

Scalability of photo-sensitizers and catalysts

Like for PV, large-scale implementation of solar fuel technology requires cheap and earth abundant materials. Today’s molecular or semiconductor photo-sensitizers and photocatalysts often contain scarce, noble (and expensive), or toxic metals, which obviously need to be replaced by more abundant and benign elements. This may take a considerable amount of time and effort, since the photophysical, photochemical, and catalytic properties of materials based on the abundant elements are frequently very different from those of the metals used today. It will require extensive development work to achieve requested properties and efficiencies of the abundant materials.

Acknowledgments

VS would like to thank S. Styring for useful discussions and for providing parts of the text on solar fuels.

Biographies

is a Professor of Biomolecular and Organic Electronic at Linköping University. His research interests are in polymer optoelectronics and bioelectronics, conjugated polymer physics, and polymer electrochemistry.

is a Professor of Chemical Physics, Lund University. His research interests are in light-induced processes in photosynthesis and materials for solar energy conversion. Various forms of time resolved laser spectroscopy are used in this research.

Contributor Information

Olle Inganäs, Email: es.uil.mfi@gnilo .

Villy Sundström, Email: [email protected] .

• Blankenship RE, Tiede DM, Barber J, Brudvig GW, Fleming G, Ghirardi M, Gunner MR, Junge W, et al. Comparing photosynthetic and photovoltaic efficiencies and recognizing the potential for improvement. Science. 2011; 332 :805–809. doi: 10.1126/science.1200165. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Cogdell RJ, Gardiner AT, Molina PI, Cronin L. The use and misuse of photosynthesis in the quest for novel methods to harness solar energy to make fuel. Philosophical Transactions of the Royal Society A. 2013; 371 :20110603. doi: 10.1098/rsta.2011.0603. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Cook TR, Dogutan DK, Reece SY, Surendranath Y, Teets TS, Nocera DG. Solar energy supply and storage for the legacy and nonlegacy worlds. Chemical Reviews. 2010; 110 :6474–6502. doi: 10.1021/cr100246c. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Hammarström L, Hammes-Schiffer S. Artificial photosynthesis and solar fuels. Accounts of Chemical Research. 2009; 42 :1859–1860. doi: 10.1021/ar900267k. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Hanna MC, Nozik AJ. Solar conversion efficiency of photovoltaic and photoelectrolysis cells with carrier multiplication absorbers. Journal of Applied Physics. 2006; 100 :074510. doi: 10.1063/1.2356795. [ CrossRef ] [ Google Scholar ]
• Heliatek. 2012. Retrieved January 10, 2015 from www.heliatek.com .
• Jeon NJ, Noh JH, Yang WS, Kim YC, Ryu S, Seo J, Seok SI. Compositional engineering of perovskite materials for high-performance solar cells. Nature. 2015; 517 :476–480. doi: 10.1038/nature14133. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Joya KS, Joya YF, Ocakoglu K, van de Krol R. Water-splitting catalysis and solar fuel devices: Artificial leaves on the move. Angewandte Chemie International Edition. 2013; 52 :10426–10437. doi: 10.1002/anie.201300136. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Kamat P, Bisquert J. Solar fuels. Photocatalytic hydrogen generation. Journal of Physical Chemistry C. 2013; 117 :14873–14875. doi: 10.1021/jp406523w. [ CrossRef ] [ Google Scholar ]
• Magnuson A, Johansson O, Polivka T, Anderlund M, Lindblad P, Styring S, Ott S, Lomoth R, et al. Biomimetic and microbial approaches to solar fuel generation. Accounts of Chemical Research. 2009; 42 :1899–1909. doi: 10.1021/ar900127h. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Miller OD, Yablonovitch E, Kurtz SR. Strong internal and external luminescence as solar cells approach the Shockley–Queisser limit. IEEE Journal of Photovoltaics. 2012; 2 :303–311. doi: 10.1109/JPHOTOV.2012.2198434. [ CrossRef ] [ Google Scholar ]
• Mitsubishi. 2013. Retrieved January 10, 2015 from http://www.m-kagaku.co.jp/english/r_td/strategy/technology/topics/opv/ .
• Nocera DG. The artificial leaf. Accounts of Chemical Research. 2012; 45 :767–776. doi: 10.1021/ar2003013. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Nocera, D., and D. Guldi. (ed.). 2009. Themed issue: Renewable energy, Chemical Society Reviews . 38: 1–300.
• Pagliaro M, Konstandopoulos AG, Ciriminna R, Palmisano G. Solar hydrogen: Fuel of the near future. Energy & Environmental Science. 2010; 3 :279–287. doi: 10.1039/b923793n. [ CrossRef ] [ Google Scholar ]
• Perez, R., and M. Perez. 2009. A fundamental look at energy reserves for the planet. IEA SHC Solar Update. Retrieved from: http://www.asrc.cestm.albany.edu/perez/Kit/pdf/a-fundamental-look-at%20the-planetary-energy-reserves.pdf .
• Poddutoori P, Co DT, Samuel APS, Kim CH, Vagnini MT, Wasielewski MR. Photoinitiated multistep charge separation in ferrocene–zinc porphyrin–diiron hydrogenase model complex triads. Energy & Environmental Science. 2011; 4 :244–2450. doi: 10.1039/c1ee01334c. [ CrossRef ] [ Google Scholar ]
• Shockley W, Queisser HJ. Detailed balance limit of efficiency of p–n junction solar cells. Journal of Applied Physics. 1961; 32 :510. doi: 10.1063/1.1736034. [ CrossRef ] [ Google Scholar ]
• Sundström, V. (ed.). 2009. Solar energy conversion Dalton Transactions. Themed Issue volume 45. [ PubMed ]
• Tamagnini P, Leita E, Oliveira P, Ferreira D, Pinto F, Harris D, Heidorn T, Lindblad P. Cyanobacterial hydrogenases: Diversity, regulation and applications. FEMS Microbiology Reviews. 2007; 31 :692–720. doi: 10.1111/j.1574-6976.2007.00085.x. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Vagnini MT, Mara MW, Harpham MR, Huang J, Shelby ML, Chen LX, Wasielewski MR. Interrogating the photogenerated Ir(IV) state of a water oxidation catalyst using ultrafast optical and X-ray absorption spectroscopy. Chemical Science. 2013; 4 :3863–3873. doi: 10.1039/c3sc51511g. [ CrossRef ] [ Google Scholar ]
• Vandewal K, Tvingstedt K, Gadisa A, Inganäs O, Manca JV. On the origin of the open-circuit voltage of polymer–fullerene solar cells. Nature Materials. 2009; 8 :904–909. doi: 10.1038/nmat2548. [ PubMed ] [ CrossRef ] [ Google Scholar ]

Notification: View the latest site access restrictions, updates, and resources related to the coronavirus (COVID-19) »

NREL's solar research strives to enable reliable, low-cost solar energy at scale—on the grid and beyond the grid.

Postdocs Study Impact of Turbulent Winds on Concentrating Solar Power

The study will help predict the impact of wind conditions on concentrating solar power performance and more

Photovoltaic Research

Concentrating solar power research, solar market research and analysis, solar grid and systems integration, solar tech to market.

NREL Shows Live Grid Impacts From Total Solar Eclipse

April 8, 2024

A Crystal Ball for Solar Modules

March 7, 2024

Nextracker and NREL Partnership Inspires New Look at PV Tracker Industry Design Standards

March 4, 2024

Solar Energy Basics

Solar Newsletters

Read the latest edition and subscribe to the solar newsletter .

For a focus on NREL's solar analysis work, subscribe to the solar market research and analysis newsletter .

• International edition
• Australia edition
• Europe edition

‘Revolutionary’ solar power cell innovations break key energy threshold

Next generation cells surpass limits of today’s cells and will accelerate rollout of cheaper, more efficient solar power

Solar power cells have raced past the key milestone of 30% energy efficiency, after innovations by multiple research groups around the world. The feat makes this a “revolutionary” year, according to one expert, and could accelerate the rollout of solar power.

Today’s solar panels use silicon-based cells but are rapidly approaching their maximum conversion of sunlight to electricity of 29%. At the same time, the installation rate of solar power needs to increase tenfold in order to tackle the climate crisis, according to scientists.

The breakthrough is adding a layer of perovskite, another semiconductor, on top of the silicon layer. This captures blue light from the visible spectrum, while the silicon captures red light, boosting the total light captured overall. With more energy absorbed per cell, the cost of solar electricity is even cheaper, and deployment can proceed faster to help keep global heating under control.

The perovskite-silicon “tandem” cells have been under research for about a decade, but recent technical improvements have now pushed them past the 30% milestone. Experts said that if the scaling-up of production of the tandem cells proceeds smoothly, they could be commercially available within five years, about the same time silicon-only cells reach their maximum efficiency.

Two groups published the details of their efficiency breakthroughs in the journal Science on Thursday, and at least two others are known to have pushed well beyond 30%.

“This year is a revolutionary year,” said Prof Stefaan De Wolf, at King Abdullah University of Science and Technology in Saudi Arabia. “It’s very exciting that things are moving rapidly with multiple groups.”

The current efficiency record for silicon-only solar cells is 24.5% in commercial cells and 27% in the laboratory. The latter may well be as close the cells can practically get to the theoretical maximum of 29%.

But one group, led by Prof Steve Albrecht at the Helmholtz Center Berlin for Materials and Energy in Germany, has now published information about how they achieved efficiencies of up to 32.5% for silicon-perovskite cells. The other group, led by Dr Xin Yu Chin at the Federal Institute of Technology in Lausanne, Switzerland, demonstrated an efficiency of 31.25% and said tandem cells had the “potential for both high efficiency and low manufacturing costs”.

“What these two groups have shown are really milestones,” said De Wolf. His own group achieved 33.7% efficiency with a tandem cell in June, but has yet to publish the results in a journal. All the efficiency measurements were independently verified.

“Overcoming the 30% threshold provides confidence that high performance, low-cost PVs can be brought to the market,” said De Wolf. Global solar power capacity reached 1.2 terawatts (TW) in 2022. “Yet to avert the catastrophic scenarios associated with global warming, the total capacity needs to increase to about 75TW by 2050,” he said.

The solar industry is also part of the race to high efficiency. Chinese company LONGi, the world’s biggest producer of solar cells, announced in June they had reached 33.5% in their research. “Reducing the cost of electricity remains the perpetual theme driving the development of the photovoltaic industry,” said Li Zhenguo, the president of LONGi.

“The industry is running very, very fast,” De Wolf said. “And I’m sure that multiple companies are working on this in China.” Europe and the US need to increase its research and development funding to keep up and contribute to an accelerating roll out of solar power, he said.

All of the high-efficiency tandem cells above 30% efficiency are small so far, measuring 1cm by 1cm. They now need to be scaled up to the size of commercial cells, which are 15cm squares or larger.

The scale-up is already under way with UK company Oxford PV announcing in May a record 28.6% efficiency for a commercial-size cell . “Solar is already one of the least expensive and cleanest forms of energy available, and our technology will make it even more affordable,” said Chris Case, chief technology officer at Oxford PV.

The Oxford PV cell was made using the same production line that is already producing commercial-sized tandem cells with 27% efficiency in increasing volumes. Tandem cells may prove to be more expensive than silicon-only cells, but the cells are only a small part of the cost of producing and installing solar panels, De Wolf said.

One issue that remains to be resolved is how fast the tandem cells degrade over time in real-world conditions. Today’s solar cells still have 80-90% of their capacity after 25 years and De Wolf said tandems would have to match that, but that there was only limited data on their stability to date.

The key to the higher efficiencies of the tandem cells from the German and Swiss groups was tackling tiny defects on the surface of the perovskite layer. These allow some electrons liberated by solar photons to flow back into the perovskite, rather than contributing to the cell’s electrical current and therefore reducing its efficiency.

The solution was to put a layer of organic molecules between the perovskite and the conducting layer through which the current flows, which compensated for the defects.

Significantly, all the groups used different methods to address the problem, giving more options in the search for the best commercial design, said De Wolf. “There’s still lots of room to go further,” he said. “I believe that the practical limit is well beyond 35%.”

Prof Rob Gross, director of the UK Energy Research Centre, said: “Solar is already a low-cost way to generate electricity and has a wide resource base across the world. The cost reductions already achieved are the main reason solar now plays such a large role in scenarios of decarbonised energy systems. Improvements in efficiency have the potential to increase the output of solar and therefore will help to reinforce that effect.”

There are other technologies, such as multi-junction cells, which can have efficiencies as high as 47% , but these are very expensive to produce and would only be suitable for niche uses such as on space satellites or when sunlight is highly concentrated on to the cells .

• Solar power
• Climate crisis
• Renewable energy

Most viewed

Solar Energy

Solar energy is created by nuclear fusion that takes place in the sun. It is necessary for life on Earth, and can be harvested for human uses such as electricity.

Earth Science, Engineering, Physics

Loading ...

Solar energy is any type of energy generated by the sun . Solar energy is created by nuclear fusion that takes place in the sun. Fusion occurs when protons of hydrogen atoms violently collide in the sun’s core and fuse to create a helium atom. This process, known as a PP (proton-proton) chain reaction, emits an enormous amount of energy. In its core, the sun fuses about 620 million metric tons of hydrogen every second. The PP chain reaction occurs in other stars that are about the size of our sun, and provides them with continuous energy and heat. The temperature for these stars is around 4 million degrees on the Kelvin scale (about 4 million degrees Celsius, 7 million degrees Fahrenheit). In stars that are about 1.3 times bigger than the sun, the CNO cycle drives the creation of energy. The CNO cycle also converts hydrogen to helium, but relies on carbon, nitrogen, and oxygen (C, N, and O) to do so. Currently , less than two percent of the sun’s energy is created by the CNO cycle. Nuclear fusion by the PP chain reaction or CNO cycle releases tremendous amounts of energy in the form of waves and particles. Solar energy is constantly flowing away from the sun and throughout the solar system . Solar energy warms Earth, causes wind and weather , and sustains plant and animal life. The energy, heat, and light from the sun flow away in the form of electromagnetic radiation (EMR). The electromagnetic spectrum exists as waves of different frequencies and wavelengths. The frequency of a wave represents how many times the wave repeats itself in a certain unit of time. Waves with very short wavelengths repeat themselves several times in a given unit of time, so they are high-frequency. In contrast, low-frequency waves have much longer wavelengths. The vast majority of electromagnetic waves are invisible to us. The most high-frequency waves emitted by the sun are gamma rays, X-rays, and ultraviolet radiation (UV rays). The most harmful UV rays are almost completely absorbed by Earth’s atmosphere . Less potent UV rays travel through the atmosphere, and can cause sunburn. The sun also emits infrared radiation , whose waves are much lower-frequency. Most heat from the sun arrives as infrared energy. Sandwiched between infrared and UV is the visible spectrum, which contains all the colors we see on Earth. The color red has the longest wavelengths (closest to infrared), and violet (closest to UV) the shortest. Natural Solar Energy Greenhouse Effect The infrared, visible, and UV waves that reach Earth take part in a process of warming the planet and making life possible—the so-called “greenhouse effect.” About 30 percent of the solar energy that reaches Earth is reflected back into space. The rest is absorbed into Earth’s atmosphere. The radiation warms Earth’s surface, and the surface radiates some of the energy back out in the form of infrared waves. As they rise through the atmosphere, they are intercepted by greenhouse gases , such as water vapor and carbon dioxide.

Greenhouse gases trap the heat that reflects back up into the atmosphere. In this way, they act like the glass walls of a greenhouse. This greenhouse effect keeps Earth warm enough to sustain life. Photosynthesis Almost all life on Earth relies on solar energy for food, either directly or indirectly. Producers rely directly on solar energy. They absorb sunlight and convert it into nutrients through a process called photosynthesis. Producers, also called autotrophs , include plants, algae, bacteria, and fungi. Autotrophs are the foundation of the food web . Consumers rely on producers for nutrients. Herbivores, carnivores, omnivores, and detritivores rely on solar energy indirectly. Herbivores eat plants and other producers. Carnivores and omnivores eat both producers and herbivores. Detritivores decompose plant and animal matter by consuming it. Fossil Fuels Photosynthesis is also responsible for all of the fossil fuels on Earth. Scientists estimate that about three billion years ago, the first autotrophs evolved in aquatic settings. Sunlight allowed plant life to thrive and evolve. After the autotrophs died, they decomposed and shifted deeper into the Earth, sometimes thousands of meters. This process continued for millions of years. Under intense pressure and high temperatures, these remains became what we know as fossil fuels. Microorganisms became petroleum, natural gas, and coal. People have developed processes for extracting these fossil fuels and using them for energy. However, fossil fuels are a nonrenewable resource . They take millions of years to form. Harnessing Solar Energy Solar energy is a renewable resource , and many technologies can harvest it directly for use in homes, businesses, schools, and hospitals. Some solar energy technologies include photovoltaic cells and panels, concentrated solar energy , and solar architecture . There are different ways of capturing solar radiation and converting it into usable energy. The methods use either active solar energy or passive solar energy . Active solar technologies use electrical or mechanical devices to actively convert solar energy into another form of energy, most often heat or electricity. Passive solar technologies do not use any external devices. Instead, they take advantage of the local climate to heat structures during the winter, and reflect heat during the summer. Photovoltaics Photovoltaics is a form of active solar technology that was discovered in 1839 by 19-year-old French physicist Alexandre-Edmond Becquerel. Becquerel discovered that when he placed silver-chloride in an acidic solution and exposed it to sunlight, the platinum electrodes attached to it generated an electric current. This process of generating electricity directly from solar radiation is called the photovoltaic effect, or photovoltaics.

Today, photovoltaics is probably the most familiar way to harness solar energy. Photovoltaic arrays usually involve solar panels , a collection of dozens or even hundreds of solar cells. Each solar cell contains a semiconductor , usually made of silicon. When the semiconductor absorbs sunlight, it knocks electrons loose. An electrical field directs these loose electrons into an electric current, flowing in one direction. Metal contacts at the top and bottom of a solar cell direct that current to an external object. The external object can be as small as a solar-powered calculator or as large as a power station. Photovoltaics was first widely used on spacecraft. Many satellites , including the International Space Station (ISS), feature wide, reflective “wings” of solar panels. The ISS has two solar array wings (SAWs), each using about 33,000 solar cells. These photovoltaic cells supply all electricity to the ISS, allowing astronauts to operate the station, safely live in space for months at a time, and conduct scientific and engineering experiments. Photovoltaic power stations have been built all over the world. The largest stations are in the United States, India, and China. These power stations emit hundreds of megawatts of electricity, used to supply homes, businesses, schools, and hospitals. Photovoltaic technology can also be installed on a smaller scale. Solar panels and cells can be fixed to the roofs or exterior walls of buildings, supplying electricity for the structure. They can be placed along roads to light highways. Solar cells are small enough to power even smaller devices, such as calculators, parking meters, trash compactors, and water pumps. Concentrated Solar Energy Another type of active solar technology is concentrated solar energy or concentrated solar power (CSP). CSP technology uses lenses and mirrors to focus (concentrate) sunlight from a large area into a much smaller area. This intense area of radiation heats a fluid, which in turn generates electricity or fuels another process. Solar furnaces are an example of concentrated solar power. There are many different types of solar furnaces, including solar power towers , parabolic troughs, and Fresnel reflectors. They use the same general method to capture and convert energy. Solar power towers use heliostats , flat mirrors that turn to follow the sun’s arc through the sky. The mirrors are arranged around a central “collector tower,” and reflect sunlight into a concentrated ray of light that shines on a focal point on the tower. In previous designs of solar power towers, the concentrated sunlight heated a container of water, which produced steam that powered a turbine . More recently, some solar power towers use liquid sodium, which has a higher heat capacity and retains heat for a longer period of time. This means that the fluid not only reaches temperatures of 773 to 1,273K (500° to 1,000° C or 932° to 1,832° F), but it can continue to boil water and generate power even when the sun is not shining. Parabolic troughs and Fresnel reflectors also use CSP, but their mirrors are shaped differently. Parabolic mirrors are curved, with a shape similar to a saddle. Fresnel reflectors use flat, thin strips of mirror to capture sunlight and direct it onto a tube of liquid. Fresnel reflectors have more surface area than parabolic troughs and can concentrate the sun’s energy to about 30 times its normal intensity. Concentrated solar power plants were first developed in the 1980s. The largest facility in the world is a series of plants in Mojave Desert in the U.S. state of California. This Solar Energy Generating System (SEGS) generates more than 650 gigawatt-hours of electricity every year. Other large and effective plants have been developed in Spain and India.

Concentrated solar power can also be used on a smaller scale. It can generate heat for solar cookers , for instance. People in villages all over the world use solar cookers to boil water for sanitation and to cook food. Solar cookers provide many advantages over wood-burning stoves: They are not a fire hazard, do not produce smoke, do not require fuel, and reduce habitat loss in forests where trees would be harvested for fuel. Solar cookers also allow villagers to pursue time for education, business, health, or family during time that was previously used for gathering firewood. Solar cookers are used in areas as diverse as Chad, Israel, India, and Peru. Solar Architecture Throughout the course of a day, solar energy is part of the process of thermal convection , or the movement of heat from a warmer space to a cooler one. When the sun rises, it begins to warm objects and material on Earth. Throughout the day, these materials absorb heat from solar radiation. At night, when the sun sets and the atmosphere has cooled, the materials release their heat back into the atmosphere. Passive solar energy techniques take advantage of this natural heating and cooling process. Homes and other buildings use passive solar energy to distribute heat efficiently and inexpensively. Calculating a building’s “ thermal mass ” is an example of this. A building’s thermal mass is the bulk of material heated throughout the day. Examples of a building’s thermal mass are wood, metal, concrete, clay, stone, or mud. At night, the thermal mass releases its heat back into the room. Effective ventilation systems—hallways, windows, and air ducts—distribute the warmed air and maintain a moderate, consistent indoor temperature. Passive solar technology is often involved in the design of a building. For example, in the planning stage of construction, the engineer or architect may align the building with the sun’s daily path to receive desirable amounts of sunlight. This method takes into account the latitude , altitude , and typical cloud cover of a specific area. In addition, buildings can be constructed or retrofitted to have thermal insulation, thermal mass, or extra shading. Other examples of passive solar architecture are cool roofs, radiant barriers , and green roofs . Cool roofs are painted white, and reflect the sun’s radiation instead of absorbing it. The white surface reduces the amount of heat that reaches the interior of the building, which in turn reduces the amount of energy that is needed to cool the building. Radiant barriers work similarly to cool roofs. They provide insulation with highly reflective materials, such as aluminum foil. The foil reflects, instead of absorbs, heat, and can reduce cooling costs up to 10 percent. In addition to roofs and attics, radiant barriers may also be installed beneath floors. Green roofs are roofs that are completely covered with vegetation . They require soil and irrigation to support the plants, and a waterproof layer beneath. Green roofs not only reduce the amount of heat that is absorbed or lost, but also provide vegetation. Through photosynthesis, the plants on green roofs absorb carbon dioxide and emit oxygen. They filter pollutants out of rainwater and air, and offset some of the effects of energy use in that space. Green roofs have been a tradition in Scandinavia for centuries, and have recently become popular in Australia, Western Europe, Canada, and the United States. For example, the Ford Motor Company covered 42,000 square meters (450,000 square feet) of its assembly plant roofs in Dearborn, Michigan, with vegetation. In addition to reducing greenhouse gas emissions, the roofs reduce stormwater runoff by absorbing several centimeters of rainfall.

Green roofs and cool roofs can also counteract the “ urban heat island ” effect. In busy cities, the temperature can be consistently higher than the surrounding areas. Many factors contribute to this: Cities are constructed of materials such as asphalt and concrete that absorb heat; tall buildings block wind and its cooling effects; and high amounts of waste heat is generated by industry, traffic, and high populations. Using the available space on the roof to plant trees, or reflecting heat with white roofs, can partially alleviate local temperature increases in urban areas. Solar Energy and People Since sunlight only shines for about half of the day in most parts of the world, solar energy technologies have to include methods of storing the energy during dark hours. Thermal mass systems use paraffin wax or various forms of salt to store the energy in the form of heat. Photovoltaic systems can send excess electricity to the local power grid , or store the energy in rechargeable batteries. There are many pros and cons to using solar energy. Advantages A major advantage to using solar energy is that it is a renewable resource. We will have a steady, limitless supply of sunlight for another five billion years. In one hour, Earth’s atmosphere receives enough sunlight to power the electricity needs of every human being on Earth for a year. Solar energy is clean. After the solar technology equipment is constructed and put in place, solar energy does not need fuel to work. It also does not emit greenhouse gases or toxic materials. Using solar energy can drastically reduce the impact we have on the environment. There are locations where solar energy is practical . Homes and buildings in areas with high amounts of sunlight and low cloud cover have the opportunity to harness the sun’s abundant energy. Solar cookers provide an excellent alternative to cooking with wood-fired stoves—on which two billion people still rely. Solar cookers provide a cleaner and safer way to sanitize water and cook food. Solar energy complements other renewable sources of energy, such as wind or hydroelectric energy . Homes or businesses that install successful solar panels can actually produce excess electricity. These homeowners or businessowners can sell energy back to the electric provider, reducing or even eliminating power bills. Disadvantages The main deterrent to using solar energy is the required equipment. Solar technology equipment is expensive. Purchasing and installing the equipment can cost tens of thousands of dollars for individual homes. Although the government often offers reduced taxes to people and businesses using solar energy, and the technology can eliminate electricity bills, the initial cost is too steep for many to consider. Solar energy equipment is also heavy. In order to retrofit or install solar panels on the roof of a building, the roof must be strong, large, and oriented toward the sun’s path. Both active and passive solar technology depend on factors that are out of our control, such as climate and cloud cover. Local areas must be studied to determine whether or not solar power would be effective in that area. Sunlight must be abundant and consistent for solar energy to be an efficient choice. In most places on Earth, sunlight’s variability makes it difficult to implement as the only source of energy.

Agua Caliente The Agua Caliente Solar Project, in Yuma, Arizona, United States, is the world's largest array of photovoltaic panels. Agua Caliente has more than five million photovoltaic modules, and generates more than 600 gigawatt-hours of electricity.

Green Chicago Millennium Park in Chicago, Illinois, United States, has one of the most expansive green roofs in the world almost 100,000 square meters (more than a million square feet). Vegetation at ground level covers 24.5 acres of an underground parking garage, and includes gardens, picnic areas, and an outdoor concert facility.

Solar Decathlon The Solar Decathlon is a biannual international event presented by the U.S. Department of Energy. Teams compete to design, build, and operate the most attractive, effective, and energy-efficient solar-powered house.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Illustrator

Last updated.

April 3, 2024

User Permissions

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text on this page is printable and can be used according to our Terms of Service .

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals

Solar energy and photovoltaic technology articles from across Nature Portfolio

Solar energy and photovoltaic technology is the study of using light from the sun as a source of energy, and the design and fabrication of devices for harnessing this potential. This involves collecting solar radiation for converting to both electricity and heat. Solar energy is carbon-free and renewable.

Latest Research and Reviews

Waterproof and ultraflexible organic photovoltaics with improved interface adhesion

Waterproof flexible organic solar cells without compromising mechanical flexibility and conformability remains challenging. Here, the authors demonstrate in-situ growth of hole-transporting layer to strengthen interfacial and thermodynamic adhesion for better waterproofness in 3 μm-thick devices.

• Sixing Xiong
• Kenjiro Fukuda
• Takao Someya

Multifunctional ytterbium oxide buffer for perovskite solar cells

Ytterbium oxide buffer layer for use in perovskite solar cells yields a certified power conversion efficiency of more than 25%, which enhances stability across a wide variety of perovskite compositions.

Near infrared emissions from both high efficient quantum cutting (173%) and nearly-pure-color upconversion in NaY(WO 4 ) 2 :Er 3+ /Yb 3+ with thermal management capability for silicon-based solar cells

The Yb 3+ emissions from both the quantum cutting and nearly-pure infrared upconversion and excellent temperature detection were realized in Er 3+ /Yb 3+ co-doped NaY(WO 4 ) 2 phosphors.

• Baojiu Chen
• Lihong Cheng

Luminescent solar concentrator efficiency enhanced via nearly lossless propagation pathways

Luminescence solar concentrators are improved by using a laminated structure that creates a practically non-decaying optical ‘guard rail’ for light. Design rules enabled external quantum efficiencies as high as 45% for 450 nm light, yielding a device efficiency of 7.6%, probably useful for energy-harvesting windows.

• Kyoungwon Park
• Jeongmin Yi
• Chul Jong Han

Infrared-reflective ultrathin-metal-film-based transparent electrode with ultralow optical loss for high efficiency in solar cells

• George Perrakis
• Anna C. Tasolamprou
• Maria Kafesaki

Efficiency limit of transition metal dichalcogenide solar cells

Transition metal dichalcogenide-based photovoltaics offer the prospect of increased specific power compared to incumbent solar technologies but there are engineering challenges that come with integrating these materials into high-efficiency devices. Here, the authors develop a model to describe the relationship between material quality and the performance limits of single junction solar cells built with various transition metal dichalcogenides.

• Koosha Nassiri Nazif
• Frederick U. Nitta

News and Comment

Unfounded concerns about photovoltaic module toxicity and waste are slowing decarbonization

Unsubstantiated claims that fuel growing public concern over the toxicity of photovoltaic modules and their waste are slowing their deployment. Clarifying these issues will help to facilitate the decarbonization that our world depends on.

• Heather Mirletz
• Henry Hieslmair
• Teresa M. Barnes

All-perovskite tandems go bifacial

• Suhas Mahesh
• Edward H. Sargent

Disorder control enhances ultrathin solar cells

Homogenized AgBiS 2 nanocrystals with enhanced light absorption have helped realize an ultrathin solar cell with a certified efficiency of 8.85%.

• Xiaoyu Yang

Metafabrics for cooling under a scorching sun

• Shuang Zhang

Ideal solar cell efficiencies

• Tom Markvart

Perovskite fever

• Mark Buchanan

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Pros and cons of solar energy

Solar power could become the primary source of electricity worldwide by 2050 – but there are still clouds in the forecast

• Newsletter sign up Newsletter

Solar power is the third largest source of renewable energy globally, behind hydropower and wind – but it's the fastest-growing. 

In 2023, three-quarters of new renewable electricity capacity came from solar power, according to the International Energy Agency .

Solar energy refers to power generated by sunlight, captured via solar panels. Most solar energy is photovoltaic (PV) – converting light into electricity – but the sun's rays can also be used to power thermal panels, which directly heat water or other liquids.

Subscribe to The Week

Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

Sign up for The Week's Free Newsletters

From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.

Climate experts are united on the need to transition to renewable energy sources, but the field of solar power is not without its concerns and controversies.

Pro: it's already working

The momentum of solar energy uptake has already passed a "tipping point" towards "irreversible" dominance, according to researchers at the University of Exeter and University College London.

Their study, published in the journal Nature Communications last year, predicted that by the middle of this century solar power "will have come to dominate the [global energy] mix". It credited the technology's wide availability and "economic attractiveness" for creating "a cycle of increasing investments" around the world.

Con: billions of panels need recycling

The 2.5 billion or so solar panels currently installed around the world will start to lose efficiency after 25 to 30 years, said the BBC , yet "specialist infrastructure to scrap and recycle them is lacking". 

With the first wave of solar panels now "approaching retirement", action is needed to create facilities to recycle them effectively.

"It's going to be a waste mountain by 2050, unless we get recycling chains going now," Ute Collier, deputy director of the International Renewable Energy Agency, told the broadcaster.

Pro: improving technology

The efficiency of solar panels has seen "significant progress" in recent years, said The Independent , "primarily boosted by the so-called 'miracle material' perovskite", which consists of calcium titanium oxide.

One of the most persistent concerns over solar panels is their capacity to generate enough energy to cover cloudy spells, but perovskite solar cells "are able to capture about 20 per cent more energy from sunlight than traditional ones made from silicon", said the Financial Times . It's no wonder the material is "the talk of solar energy circles", although production would need to ramp up significantly if they were to become standard on the global market.

Con: vast solar farms

Rooftop solar panels can supply power effectively to individual homes and businesses, but harnessing solar energy on a wider level means massive solar farms.

For instance, the planned Botley West mega farm in Oxfordshire, which would supply energy to an estimated 330,000 homes, would take up about five square miles of countryside. Proposals such as this one are putting "the frontline of the battle to go green… in rural community halls", said Politico .

Botley West has provoked a fierce backlash, from concerns over the impact on wildlife to local residents "grumpy about potential noise and bucolic views being spoiled", the news site said.

Pro: the sky's not the limit

Solar farms in space would be a novel way to avoid protests over spoiled countryside – and they're closer than you might think.

Until a few years ago, the idea would have been "dismissed as science fiction", said Sky News science correspondent Thomas Moore, but now governments and private companies alike are investing in plans to launch specially designed systems of solar panels into orbit.

Solar panels would "capture 13 times more energy in space than they do on the ground", Moore said, so even allowing for energy lost while being beamed back to Earth, "it would still far outstrip solar generation on the ground".

Con: China's dominance

Even as uptake of solar energy increases worldwide, Europe-based manufacturers of solar cells are scaling back production or even going bankrupt because "in some cases 95%" of panels and parts installed in Europe come from China, said Reuters .

Chinese manufacturers offer lower prices than their Western counterparts, but reliance on China raises questions over "cybersecurity and sustainability", as well as labour practices. Almost half of the polysilicon used in solar panel production comes from the Xinjiang Autonomous Region – home to China's Uighur Muslim minority, who are regularly subjected to forced labour.

The European Commission's recent Solar Charter introduced measures designed to "help European clean tech manufacturers compete with foreign suppliers", Reuters said, but still chose to "steer clear of restrictions on cheap panel imports from China".

Sign up for Today's Best Articles in your inbox

A free daily email with the biggest news stories of the day – and the best features from TheWeek.com

Rebecca Messina is the deputy editor of The Week's UK digital team. She first joined The Week in 2015 as an editorial assistant, later becoming a staff writer and then deputy news editor, and was also a founding panellist on "The Week Unwrapped" podcast. In 2019, she became digital editor on lifestyle magazines in Bristol, in which role she oversaw the launch of interiors website YourHomeStyle.uk, before returning to The Week in 2024.

Cartoons Artists take on courtroom tranquility, war on wokeness, and more

By The Week US Published 20 April 24

In depth The writer's fall from grace with his high-flying socialite friends in 1960s Manhattan is captured in a new Disney+ series

By Adrienne Wyper, The Week UK Published 20 April 24

Why Everyone's Talking About Masters victory is Scheffler's second in three years

By The Week Staff Published 20 April 24

Today's Big Question The nation's power grid appears to be reaching critical levels due to emerging technologies

By Justin Klawans, The Week US Published 7 March 24

Under The Radar Huge deposits found in northern France but major energy companies are holding back, for now

By Chas Newkey-Burden, The Week UK Published 20 February 24

The Explainer Britain has committed to reaching net-zero carbon emissions by 2050. What will this involve?

By The Week Staff Published 3 February 24

Under the radar All thanks to perovskite solar panel technology

By Devika Rao, The Week US Published 30 January 24

Today's Big Question 'Record' global consumption is set to fall soon but growing demand in China and India could increase tensions

By Harriet Marsden, The Week UK Published 11 January 24

The Explainer The fossil fuel has replaced coal as the top source of electricity in the U.S. Is that good for the climate?

By The Week US Published 18 December 23

The Explainer Unpredictable gas markets threaten to cause further problems and price hikes

By Keumars Afifi-Sabet Published 18 September 23

Talking Point Britain's failed offshore wind auction debacle 'highlights an inconvenient truth'

By The Week Staff Published 14 September 23

• Contact Future's experts
• Terms and Conditions
• Privacy Policy
• Cookie Policy
• Advertise With Us

The Week is part of Future plc, an international media group and leading digital publisher. Visit our corporate site . © Future US, Inc. Full 7th Floor, 130 West 42nd Street, New York, NY 10036.

We've updated our Privacy Policy to make it clearer how we use your personal data. We use cookies to provide you with a better experience. You can read our Cookie Policy here.

Applied Sciences

Stay up to date on the topics that matter to you

Energy Scientists Unravel the Mystery of Gold’s Glow

New research has unraveled the mystery behind the nanoscale behavior of electrons as the absorb and re-emit light in gold..

Complete the form below to unlock access to ALL audio articles.

Luminescence, or the emission of photons by a substance exposed to light, has been known to occur in semiconductor materials like silicon for hundreds of years. The nanoscale behavior of electrons as they absorb and then re-emit light can tell researchers a great deal about the properties of semiconductors, which is why they are often used as probes to characterize electronic processes, like those occurring inside solar cells.

In 1969, scientists discovered that all metals luminesce to some degree, but the intervening years failed to yield a clear understanding of how this occurs.

Renewed interest in this light emission, driven by nanoscale temperature mapping and photochemistry applications, has reignited the debate surrounding its origins. But the answer was still unclear – until now.

“We developed very high-quality metal gold films, which put us in a unique position to elucidate this process without the confounding factors of previous experiments,” says Giulia Tagliabue, head of the Laboratory of Nanoscience for Energy Technologies ( LNET ) in the School of Engineering.

In a recent study published in  Light: Science and Applications ,  Tagliabue and the LNET team focused laser beams at the extremely thin – between 13 and 113 nanometers – gold films, and then analyzed the resulting faint glow. The data generated from their precise experiments was so detailed – and so unexpected – that they collaborated with theoreticians at the Barcelona Institute of Science and Technology, the University of Southern Denmark, and the Rensselaer Polytechnic Institute (USA) to rework and apply quantum mechanical modelling methods.

Want more breaking news?

Subscribe to Technology Networks ’ daily newsletter, delivering breaking science news straight to your inbox every day.

Unexpected quantum effects

Tagliabue explains that, using a thin film of monocrystalline gold produced with a novel synthesis technique, the team studied the photoluminescence process as they made the metal thinner and thinner. “We observed certain quantum mechanical effects emerging in films of up to about 40 nanometers, which was unexpected, because normally for a metal, you don’t see such effects until you go well below 10 nm,” she says.

These observations provided key spatial information about exactly where the photoluminescence process occurred in the gold, which is a prerequisite for the metal’s use as a probe. Another unexpected outcome of the study was the discovery that the gold’s photoluminescent (Stokes) signal could be used to probe the material’s own surface temperature – a boon for scientists working at the nanoscale.

“For many chemical reactions on the surface of metals, there is a big debate about why and under what conditions these reactions occur. Temperature is a key parameter, but measuring temperature at the nanoscale is extremely difficult, because a thermometer can influence your measurement. So, it’s a huge advantage to be able to probe a material using the material itself as the probe,” Tagliabue says.

A gold standard for solar fuel development

The researchers believe their findings will allow metals to be used to obtain unprecedentedly detailed insights into chemical reactions, especially those involved in energy research. Metals like gold and copper – the LNET’s next research target – can trigger certain key reactions, like the reduction of carbon dioxide (CO2) back into carbon-based products like solar fuels, which store solar energy in chemical bonds.

“To combat climate change, we are going to need technologies to convert CO2 into other useful chemicals one way or another,” says LNET postdoc Alan Bowman, the study’s first author.

“Using metals is one way to do that, but if we don’t have a good understanding of how these reactions happen on their surfaces, then we can’t optimize them. Luminescence offers a new way to understand what is happening in these metals.

Reference:  Bowman AR, Rodríguez Echarri A, Kiani F, et al. Quantum-mechanical effects in photoluminescence from thin crystalline gold films. Light Sci Appl . 2024;13(1):91. doi: 10.1038/s41377-024-01408-2

This article has been republished from the following materials . Note: material may have been edited for length and content. For further information, please contact the cited source. Our press release publishing policy can be accessed here .

Japanese satellite will beam solar power to Earth in 2025

L ONDON — Japan is on track to beam solar power from space to Earth next year, two years after a similar feat was achieved by U.S. engineers. The development marks an important step toward a possible space-based solar power station that could help wean the world off fossil fuels amid the intensifying battle against climate change . 

Speaking at the International Conference on Energy from Space, held here this week, Koichi Ijichi, an adviser at the Japanese research institute Japan Space Systems, outlined Japan's road map toward an orbital demonstration of a miniature space-based solar power plant that will wirelessly transmit energy from low Earth orbit to Earth.

"It will be a small satellite, about 180 kilograms [400 pounds], that will transmit about 1 kilowatt of power from the altitude of 400 kilometers [250 miles]," Ijichi said at the conference. 

Related: Space-based solar power may be one step closer to reality, thanks to this key test (video)

One kilowatt is about the amount of power needed to run a household appliance, such as a small dishwasher, for about an hour, depending on its size. Therefore, the demonstration is nowhere near the scale required for commercial use.

The spacecraft will use a 22-square-foot (2 square meters) onboard photovoltaic panel to charge a battery. The accumulated energy will then be transformed into microwaves and beamed toward a receiving antenna on Earth . Because the spacecraft travels very fast — around 17,400 mph (28,000 km/h) — antenna elements will have to be spread over a distance of about 25 miles (40 km), spaced 3 miles (5 km) apart, to allow enough energy to be transmitted.

"The transmission will take only a few minutes," Ijichi said. "But once the battery is empty, it will take several days to recharge."

The mission, part of a project called OHISAMA (Japanese for "sun"), is on track for launch in 2025. The researchers have already demonstrated wireless transmission of solar power on the ground from a stationary source, and they plan to conduct a transmission from an aircraft in December. The aircraft will be fitted with an identical photovoltaic panel as will be flown on the spacecraft and will beam down power over a distance of 3 to 4 miles (5 to 7 km), according to Ijichi.

From concept to reality 

Space-based solar power generation, first described in 1968 by former Apollo engineer

Peter Glaser , has been considered science fiction. Although theoretically feasible, the technology has been seen as impractical and too costly, as it requires enormous structures to be assembled in orbit to produce the required power output. 

But according to the experts speaking at the conference, that situation has changed as a result of recent technological advances and the urgency to decarbonize the world's power supply to thwart climate change.

Unlike most renewable power generation technologies used on Earth, including solar power and wind energy, space-based solar power could be available constantly, as it would not depend on weather and the time of the day. Currently, nuclear power plants or gas- and coal-fired power stations are used to cover demand when the wind stops blowing or after sunset. Improvements in technology could help partially solve the problem in the future. But some pieces of the puzzle are still missing to secure a seamless carbon-neutral power supply by the middle of this century as stipulated in international climate change agreements.

Developments in robotic technologies, improvements in the efficiency of wireless power transmission and, most importantly, the arrival of SpaceX's giant rocket Starship could allow space-based solar power to become a reality, the experts said at the conference. 

Last year, a satellite built by Caltech engineers as part of the Space Solar Power Demonstrator mission beamed solar power from space for the first time . The mission, which concluded in January, was celebrated as a major milestone. 

Many more space-based solar power demonstration projects are in the pipeline. The technology is studied by space and research agencies all over the world, including the European Space Agency , the Defense Advanced Research Projects Agency and the U.S. Air Force. Commercial companies and startups are also developing concepts, harnessing the availability of Starship and the emergence of advanced space robotics.

However, not everyone is enthusiastic about the potential of space-based solar power. In January, NASA released a report questioning the feasibility of the technology . The difficulty and amount of energy required to build, launch and assemble orbital power stations mean the energy they produce would be too expensive — 61 cents per kilowatt-hour, compared with as little as 5 cents per kilowatt-hour for Earth-based solar or wind energy. 

In addition, the overall carbon footprint of the power production and the amount of greenhouse gas emissions generated by rockets taking those assemblies into orbit make space-based solar power much less climate-friendly than technologies used on Earth. For example, a gigawatt-scale spaceborne solar power station, such as the CASSIOPeiA concept plant proposed by the U.K. firm Space Solar, would need 68 Starships to get to space.