Solar energy, in its various forms, could supply not only the bulk of the world's electricity, but also more than two-thirds of the world's primary energy production, according to several recent scientific studies, and would be unrivalled in terms of competitiveness. This energy transition would halve our global CO2 emissions and avoid the climate catastrophe that has been predicted. So, what's new under the sun?
In 2018, according to the International Energy Agency (IEA), solar power plants produced 571 terawatt hours of electricity and wind farms 1,149 terawatt hours. In 2010, wind power barely exceeded 330 terawatt hours, while solar power did not yet exist on a large scale.
Today, renewable energies already provide 26 % of the world's electricity production (26,500 TWh), of which 13 % are wind power and only 2 % are solar power. But the latter two technologies are rapidly gaining ground. The share of renewables is expected to rise to 55 % by 2040, according to the International Energy Agency (IEA). Photovoltaics and wind power would account for more than half of this growth in the scenario based on government energy targets. These two sources could provide more electricity than hydropower as early as 2030. Photovoltaics would be the main driver, with 60 % additional renewable electricity generation capacity installed by 2024.
In its Renewables 2019 reportThe IEA had already noted the growth in renewable electricity generation capacity. Additional installed capacity is expected to jump this year by 12 % (198 GW), while it had remained stable between 2017 and 2018 (178 GW). The IEA projects 1 200 GW of additional renewable capacity by 2024, equivalent to the total capacity of the United States today. Solar photovoltaic (PV) is expected to grow " spectaculaire " to 75 % from distributed systems (rooftop installations on homes, commercial and industrial buildings, as opposed to ground-based PV plants).
The installed capacity of distributed solar photovoltaic (PV) could more than double by 2024 to 530 GW. Notably thanks to China, which is expected to overtake the European Union as early as 2021 and become a leader in this field. Another factor has proved decisive in explaining this irresistible growth in solar energy: for the past ten years, the cost of electricity produced in solar power plants has been divided by nine, according to a study by the Lazard bank. The real cost of solar and wind power is now almost everywhere lower than that of fossil fuels or nuclear power.
Hybrid power plants in full bloom
All over the world, solar installations are flourishing and playing an increasing role in the energy transition and economic development of many developing countries. This is for example the case in Africa, where the consortium formed by the French company EDF Renouvelables, Masdar - a new energy company in the emirate of Abu Dhabi - and Green of Africa - an independent Moroccan electricity producer - is building the first phase of the Noor Midelt 1 hybrid solar power plant.
This future complex, located 20 kilometres from the town of Midelt, is based on a particularly promising mixed technology that combines the proven solar panel technology, widely used throughout the world, with the highly efficient, but even less well mastered, heat concentration technology. « By combining photovoltaic technologies and concentrated heat in a single facility, the proposed plant will have improved efficiency and storage capacity to generate electricity up to five hours after sunset. "EDF stated in a press release that "thehe hybridization of these technologies is a world first. ".
700 million, is in the launch phase. The future multi-technology complex is due to enter into service in 2022. Eventually, it will have a capacity of 800 MW, the equivalent of a nuclear reactor. It is currently one of the world's largest solar hybrid technology projects. With this hybrid technology and its large desert areas, Morocco intends to further strengthen its energy autonomy in the future. Initially, its objective will already be to increase the share of renewable energy to 52 % by 2030.
The other outstanding example of a hybrid power plant is Australian. In this immense country, which enjoys an exceptional amount of sunshine, the renewable energy company Windlab is currently working on a 3-in-1 hybrid power plant project. This tri-technology project aims to bring together a solar power plant, a wind farm and a lithium-ion battery storage system. The whole would be directly connected to the electricity grid. The project, called Kennedy Energy Park, has already been given the green light and construction is due to start in the coming weeks. In detail, the solar power plant is expected to provide 15 MW, the wind farm is expected to produce 43.2 MW, and both production units will be connected to Tesla batteries with a storage capacity of 4 MWh.
But solar hybrid technology is not only available in large installations, which combine concentrated thermal solar panels (which produce heat) and photovoltaic panels (which produce electricity). It can also be applied in a particularly efficient way, both in terms of efficiency and longevity, in small domestic installations, this time using mixed solar panels capable of producing heat and electricity simultaneously.
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In France, the DualSun company has made a name for itself worldwide by developing a remarkable innovation, a double-sided solar panel, named Wave, which combines two technologies: photovoltaic, to produce electricity, and thermal, to produce hot water. Its operation is relatively simple: tiny pipes cover the entire lower surface of the panel, allowing water to be distributed under the photovoltaic cells. The water enters a corner of the panel, heats up on contact with the cells and is then returned to the house, towards the hot water tank. The circuit incorporates a timer that measures the water temperature and triggers the circulation as soon as it drops below 20 degrees. At the end of the day, after making several loops, the water returns to the tank at about 60 degrees.
This mixed system not only makes it possible to provide 30 to 50 % of domestic hot water with a dozen panels in sunny regions, but it can also cool the panel thanks to this water circulation and thus extend its lifespan. This hybrid technology therefore makes it possible to produce more energy, for longer, while making substantial savings over time. It is estimated that, for a typical installation of 6 hybrid panels in the South of France, if we take into account the purchase and maintenance of the equipment over its lifetime, we obtain an overall energy cost of around 8 euro cents per kWh, which is much lower than the kWh purchased from EDF, whose basic tariff is currently around 14 euro cents including tax.
The energy efficiency and economic profitability of hybrid solar energy, which are beginning to be recognized by individuals and communities alike, have been detailed and confirmed in the thesis of Laetitia Brottier which shows that a domestic hybrid installation representing an investment of 8 500 euros (aid deducted) can generate more than 15 000 euros in savings over 20 years. This thesis also shows that this hybrid solar technology has made it possible to reduce the final energy consumption of 73 homes in Marseille by a factor of four. Another example evoked by this thesis: in Sète, the installation of 300 m² of hybrid solar panels on a shaded area for the indoor swimming pool allowed 2.5 times more energy production than a simple photovoltaic installation, which shows the effectiveness of this technology in optimising the available sunny surfaces and moving faster towards energy self-sufficient new buildings.
FOPS solar power plants
The second technological revolution in progress in the field of solar energy, which is moreover completely compatible with that of hybrid solar energy, is that of FOPS, the Organic Photovoltaic Solar Films. Flexible, ultra-thin, light, semi-transparent and inexpensive, organic photovoltaic films are produced by low-carbon processes that do not require the use of any strategic metals or chlorinated solvents. Instead of silicon, these films use carbon derivatives, hence the name "organic" cell.
Due to their remarkable physical and chemical characteristics, FOPS can be applied on almost any type of surface, building walls, but also windows, vehicles, clothing and various objects. Because of its translucent properties, this type of solar film can also be deployed on agricultural greenhouses, opening up vast prospects for farmers, both in terms of improved yields and clean local energy production. In addition, organic films have the great advantage of being insensitive to heat and their efficiency remains constant even in heat waves.
In addition to the Rhine, the German firm Heliatek, which has joined forces with the best German research institutes, has succeeded, in ten years, in increasing the output of these FOPS from 3 to 13 %, and is aiming for 15 % by 2025. Although this efficiency is still lower than that of recent solar cells, which exceed 20 %, this handicap is more than compensated for by the much wider field of use of these solar films and their low cost.
In France, one of Heliatek's main competitors is the Breton company Armor. This Nantes-based company, founded in 1922, originally manufactured cartridges for printers, before moving towards the printing of organic photovoltaic modules. Accompanied by scientists from INES and CNRS, it has developed an ultra-thin and very light OPV film (450 g/m²) with a 20-year lifespan and an energy yield of 8 %. Armor supplies the OPV film used by an interactive street furniture concept from JCDecaux, allowing information and events concerning a neighbourhood to be communicated via smartphones. Armor also equips agricultural greenhouses in partnership with Eiffage Energie. This Breton firm is convinced of the immense worldwide potential of FOPS and is multiplying experiments and projects. In particular, it has signed a contract with UNESCO as part of an operation to support education in Africa. In this project, several hundred schoolchildren in Togo were given a schoolbag with an organic photovoltaic film free of charge. It enables them to charge a mobile lamp during the day and then use this lamp in the evening to study, which changes their lives, as these schoolchildren live in rural areas that are not connected to the electricity grid.
Meanwhile, research is being actively pursued around the world to develop solar cells and films that are flexible, durable and inexpensive, and can be used on just about any surface. Researchers at the National University of Science and Technology in Ulsan (Unist), South Korea, for example, have come up with the idea of drilling tiny holes in conventional solar cells, about 100 μm, the thickness of a human hair. These tiny holes make the cell as transparent as tinted glass. This new type of cell already achieves the remarkable efficiency of 12 %. More importantly, they lose less than 4 % of efficiency when placed vertically, whereas conventional cells lose a third of their efficiency in the same exposure situation. Eventually, this new type of solar cell could be directly integrated into the windows of buildings and houses, which have the advantage of representing much larger usable surfaces than those of roofs.
A fully transparent solar panel was also recently developed by researchers at Michigan State University. They claim that this technology could have immense energy-saving potential and could be used in architecture, mobile electronics, homes, construction and even the automotive industry. The cell uses an organic technology that absorbs wavelengths of light invisible to the human eye. "Captured light is transported around the edge of the panel, where it is converted into electricity using thin strips of photovoltaic solar cells," says Richard Lunt, assistant professor of chemical engineering and materials science at MSU College of Engineering. The technology is intended to replace existing windows, particularly those in large buildings and skyscrapers because of their size.
An impressive rise in power
A growing number of scientists are convinced that the large-scale combined use of hybrid solar energy and FOPS will significantly accelerate the already impressive rise of solar energy in the global energy mix. Significantly, while in 2010 the IEA predicted that solar energy would account for 22 % of global electricity production in 2050 (already a very large share given the energy landscape at the time), it has re-estimated this share (in 2050) to 27 % in 2014 and 33 % in 2016.
But some recent studies go even further. LThe study, published in March 2019 by experts from the Finnish LUT University and the Energy Watch Group shows, for example, that it is now possible to imagine a global energy scenario for 2050 in which solar energy, in its various forms, would provide not only the bulk of the world's electricity but also more than two-thirds of the world's primary energy production. The study points out that with solar electricity costing just 5 euro cents per kWh to produce, solar would become unrivalled in terms of competitiveness. This accelerated energy transition would halve our global CO2 emissions and avert the predicted climate catastrophe, if we stay on the current trajectory of 1.5 %, as an annual average, of global CO2 emissions increase.
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In France, we now have a combination of technological skills and an awareness of the climate and environmental emergency and we must take advantage of this momentum to make our country a pioneering nation in this "solar shift". Let's be voluntary and ambitious: why not decide that before the end of this new decade, all new buildings and new individual homes should be self-sufficient in energy. We could also, taking up the conclusions of the Energy Union Choices study conducted by the Artelys firm in 2018, decide to increase the total share of renewable energies in our energy mix from 33 to 51 % in 2030, which is quite feasible, by exploiting our remarkable national solar potential in a more proactive way. The time has come to mobilize all our intelligence and resources to finally fully exploit all this clean, inexhaustible and free energy that humanity needs.
René TRÉGOUËT, Honorary Senator - Founder of the Senate Foresight Panel
(Source : RTFlash, 07/02/2020)