![](\"\/wp-content\/uploads\/2021\/11\/072-075_heliotermicas_307-0-desktop-true.jpg\")
\n <\/picture><\/div>The experimental power plant in S\u00e3o Paulo will consist of six rows of aluminum mirrors coated with a reflective film. Each of the 576 rectangular mirrors is 7 meters long by 64 centimeters wide, and each row is 150 meters long. \u201cAluminum has a longer useful life and is easier to assemble than glass mirrors,\u201d explains Luis Paschoalotto, the manager of Operations and Maintenance Engineering at CESP. The material was imported from the United States.<\/p>\n
One advantage of CSP plants is that heat storage allows them to continue to generate energy after the sun is no longer shining on the system, since the flow of heated fluid can be controlled such that the electric generator keeps operating. \u201cIt’s an important feature, which allows the plant to be ‘dispatchable,’\u201d Paschoalotto emphasizes. Dispatchable, in electricity sector jargon, means that generation can continue even when the energy source\u2014in this case sunlight\u2014isn’t available at the time, such as at night. In a large solar thermal plant, power generation can be extended for up to 18 hours. Photovoltaic and wind energy are intermittent, so power generation ceases immediately when there is no light or wind.<\/p>\n
The CESP project was conceived in response to a 2015 public request for proposals (RFP) by the National Electric Energy Agency (ANEEL), whose objective was to collect data capable of promoting a national strategy for developing solar thermal power generation. \u201cIn our project completion report, we intend to inform ANEEL that although the technology still has a higher unit cost than other sources, it has other important attributes, because it generates renewable and controllable energy. It needs to be incentivized,\u201d Paschoalotto states.<\/p>\n
Some specialists recommend that specific energy purchase auctions be held for CSP generation until the energy source achieves scale and becomes competitive. This was the mechanism adopted to encourage wind and photovoltaic energy during their early years in Brazil.<\/p>\n
Solar thermal generation is still in its infancy throughout the world. The International Renewable Energy Agency (IRENA) estimated that installed solar power generation capacity totaled 713.9 gigawatts (GW) in 2020. Of this total, 707.5 GW are obtained with photovoltaic generation, while only 6.4 GW come from CSP systems.<\/p>\n
Paulo Cunha, a researcher at the Energy Studies Center of the Getulio Vargas Foundation (FGV Energia), observes that the photovoltaic equipment industry has made significant progress over the last 10 years. During this period, there was a reduction in the average cost of generation from US$0.378 per kilowatt-hour (KWh) in 2010 to US$0.068 per KWh in 2019, according to IRENA data. Cunha believes this is why photovoltaic generation systems became popular. During the same period, the CSP generation equipment industry did not evolve, and several suppliers of solar panels and heat receivers closed down. The cost of solar thermal generation, according to IRENA, is US$0.182 per kWh, about 2.5 times higher than that of photovoltaic power (see infographic below<\/em>).<\/p>\n The Electric Power Generation and Transmission Company of Southern Brazil (ELETROSUL), and Neoenergia, of the Spanish Iberdrola group, which operate in 18 Brazilian states, also submitted projects for the ANEEL request for proposals. When contacted for this report, they did not wish to comment. Another company that responded to the ANEEL RFP was Companhia Hidrel\u00e9trica do S\u00e3o Francisco (CHESF). Jos\u00e9 Bione de Melo Filho, manager of the company’s Research, Development, and Innovation Department, says that the company’s objective is to build two experimental plants in Petrolina, Pernambuco, the first using parabolic trough technology and the other employing a central tower, like the Chilean Cerro Dominador facility.<\/p>\n The parabolic trough plant will generate 0.8 MW of power, with installation work expected to start this year, as soon as the project obtains environmental licensing. Another pending issue is the acquisition of the concave mirrors needed to capture and reflect solar radiation to the focal point. \u201cBrazil does not have the know-how to fabricate these mirrors. That\u2019s the main bottleneck,\u201d says Melo Filho. There is still no forecast regarding the construction of the central tower generation plant.<\/p>\n At the School of Animal Science and Food Engineering of the University of S\u00e3o Paulo (FZEA-USP), Pirassununga campus, an experimental CSP project is expected to start operating in 2022. Their plant design is distinguished by being a hybrid electricity generation system linked with heat cogeneration for industrial use.<\/p>\n Solar generation will be obtained with the use of 74 heliostats, each formed by 9 square mirrors of Brazilian glass. They are 9 m2<\/sup> each and will be aimed at a focal point at the top of a 25-meter central tower. The CSP will have an installed power capacity of 70 KW. \u201cWhen there’s a lack of sunshine, the turbine will be powered by biofuel, which is the reason the system is hybrid,\u201d explains FZEA professor Celso Eduardo Lins de Oliveira, coordinator of the Research Group on Recycling, Energy Efficiency, and Numerical Simulation (GREEN-USP).<\/p>\n![](\"\/wp-content\/uploads\/2021\/11\/072-075_heliotermicas_307-1-desktop-corrigido.png\")
\n <\/picture>\n
![\"\"](\"https:\/\/revistapesquisa.fapesp.br\/wp-content\/uploads\/2021\/11\/072-075_heliotermicas_307-1-1140.jpg\")