2023-09-20 19:10:32
A station capable of capturing solar energy in space, then sending it back to Earth. The project has the feel of a gentle science fiction fantasy. The author Isaac Asimov himself was not mistaken, enjoying imagining a similar device in Raisonshort story published in 1941.
Several decades later, the idea has nevertheless gained ground, passing from the fertile imagination of novelists to the technical rigor of engineers. The process? Solar energy is collected by geostationary satellites 36,000 km from Earth, equipped with panels 1,700 meters in diameter, then sent in the form of microwaves to a terrestrial power plant with a surface area ten times greater where it is then converted into electricity. An operation already successful in March 2023 by teams from the California Institute of Technology, and tested for three years by the American army.
Solaris Project
Enough to arouse the interest of certain nations, galvanized by the promises of solar production insensitive to night and weather conditions: it could work 99% of the time. In November 2022, the European Space Agency (ESA) approved the Solaris experimental project.
Nine months later, at the end of July, the agency entrusted the Franco-Italian joint venture Thales Alenia Space with the task of studying the relevance of the project. “The objective is to examine the concept in depth, and to know whether we should develop this technology or notspecifies Sanjay Vijendran, project director for ESA. The important thing for the ESA is to ensure the viability of the project, both in terms of costs but also in terms of climate and health. »
Could the waves have a negative effect on the ozone layer or promote cancer risks? What about the potential frequency conflict with television or radio, or the risk of collision with space debris orbiting the Earth? And does the project constitute a real solution, or a simple technological headlong rush in the face of climate change? ” We do not know yet. So you have to study before going there,” underlines the physicist.
Chinese and British ambitions
Other nations do not bother with such precautions. China for example, whose option on the subject is being played out in Chengdu. The city may well be shrouded in fog for a third of the year and make terrestrial solar promoters shudder, but it intends to be a pioneer in space solar, welcoming a 13-hectare site dedicated to the project since 2021.
In 2021, with the China Science DailyChinese Academy of Sciences researcher Ge Changchun prophesied that “in the second half of the 21st century, China will have built a space solar industry, which will be a flagship element of Chinese energy infrastructure”.
The United Kingdom is also determined, obsessed with a report published in 2021 by the Frazer-Nash Consultancy firm. According to him, space solar power plants would be feasible and profitable. In June 2023, Grant Shapps, British Secretary of State for Energy Security, stated: “By winning this new space race, we can transform the way we power our nation. »
Statements which are however based on the full potential of the project. For the moment, scientists are observing very significant losses when converting current into microwaves and vice versa. London is already taking steps, funding start-ups and universities with millions to develop national technology.
Beyond the Americans, Europeans, British and Chinese, a whole constellation of actors are beginning to take an interest in the subject. Faced ultimately with a lack of surface area to develop land-based renewables, South Korea remains alert, while Japan plans to test the technology by 2025. Saudi Arabia is already participating in financing the English project.
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A little more powerful than a nuclear reactor
According to estimates from Frazer-Nash Consultancy, a 2,000-ton satellite clad in solar panels would have a potential power of 2 gigawatts (GW), enough to supply the energy of 6 million solar panels on Earth and provide electricity to 1 million homes. For comparison, that of an EPR type nuclear reactor is 1.6 GW.
The first station of this type would cost less than 19 billion euros to produce. According to the study, which dates from 2021, the cost of producing electricity could be €58 per MWh, compared to €38 for terrestrial solar, €49 for wind and €113 for nuclear.
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