Space solar energy dream begins to take shape

Capturing solar energy in space and transmitting it to Earth has been a dream cherished by man for decades, which for various avatars was always left in the drawer. Either because it requires huge investments, or because there was not yet enough technology or because no one made the political and/or business decision to undertake a project of such magnitude. But that's past times. There are already space agencies, companies and scientific and academic institutions convinced that it is a great solution to contribute to the mix of renewables with which many countries want to achieve climate neutrality. An objective that Europe has set itself to lead by doing so in 2050. Hence, the European Space Agency (ESA) has taken the first step to build a future space solar station. And also the United Kingdom, which wants to carry out the first orbital demonstration in 2030 to deliver energy to its electricity grid in 2040. To do this, it has involved a large group of organizations, including companies such as Airbus and SSTL and institutions such as the University of Cambridge. In the United States, the feasibility of such a project is being reviewed and a team of scientists from the Naval Research Laboratory has already tested a prototype solar panel that can capture and send energy with microwave technology. It would be the germ of a future system to bring electricity from space to Earth. China has been working for ten years on a program to develop its solar station in orbit and has announced that it will test it in 2030. There are other initiatives in Russia, India, Japan... Within reach The idea of ​​capturing solar energy in the space and sending it to Earth is not crazy. And yes, it is possible, as different studies have shown. The latter have been ordered this year by the European Space Agency (ESA) to the British consultant Frazer-Nash and the German Ronald Berger. The engineers of both conclude that it is a viable technology when it comes to balancing its costs and long-term benefits. Moreover, they estimate that a solar plant in space could start operating as early as 2040. "It could offer profitable electricity generation compared to oil, coal, gas and biomass," reads one of these documents. . In 2025, Europe will decide whether to undertake a program to build a solar space station With this information, the ESA will propose the Solaris program to its next council of ministers, in November this year, an initiative that will involve industry and will have an initial investment limited. “It is an exploratory step that will be carried out between 2023 and 2025 to understand and demonstrate if it is really feasible, technically and economically, to develop a system of this type in the next 10 or 15 years”, specifies Sanjay Vijendran, leader of the Research Team. Mars Exploration Strategy and Coordinator of the MarsX Team at ESA. This agency has even "asked European companies to express their interest in developing this technology and in participating in a future project to obtain solar energy from space," says Antonio Abad, technical director of Hispasat. If in 2025 the go-ahead is given to undertake the program of a future European space solar station, it will drag many leading, emerging, startup companies... from various sectors, not only space, but also energy, technology, telecommunications... No interruptions Space solar power is considered for its many advantages. It is clean and, above all, constant, that is to say that a solar space station would receive sunlight practically always: 24 hours a day and 365 days a year. Without interruptions: without clouds, nights, or other weather or atmospheric incidents that can cover the radiation that comes from the sun, as it happens on Earth. In this way, it would compensate for the cyclical nature of renewables here on earth and that they are not capable of satisfying all the energy demand. Space "has much more energy available per square metre, as the atmosphere doesn't absorb the energy," says Jean-Dominique Coste, head of the SBSP (space-based solar power) program at Airbus. It is estimated that sunlight is ten times more intense there than on Earth. Desktop code Image for mobile, amp and app Mobile code AMP code APP code 2490 And the benefits are also many, as the reports made for the ESA highlight: it would help curb climate change, Europe would reduce its energy dependence and we could even sell energy to third countries. Europe would also make a great technological leap generating new applications, creating new products and markets. But nobody says that the road is easy. Although the studies state that it is technically feasible, “that does not mean that the technology is available. We have the foundations, but the levels of technological maturity are still low”, highlights Antonio Abad. ESA itself acknowledges this: “The building blocks for the key technologies already exist, but their performance needs to be drastically increased and their cost reduced in order to build an economically competitive solar power station. Therefore, there is still a lot of technological development to be done to see how far this can be achieved before we can be sure that it is feasible”, estimates Sanjay Vijendran. A solar plant in the cosmos would have kilometric dimensions A solar plant in space would have colossal dimensions. "In fact, to replace a nuclear power plant, the station would be located in the range of kilometers," describes Jean-Dominique Coste. To serve an example: The largest man-made structure in the cosmos is the International Space Station (ISS) with a total area of ​​about 8,000 square meters and weighs about 455 tons. One of the reports made for the ESA estimates that the solar station would have about 15 square kilometers and 6,000 tons. To build it, it is necessary to move thousands of solar panels, modular parts... With such dimensions, launchers that can carry heavy loads and can carry out multiple missions are needed. Quite a challenge, as Antonio Abad explains: The key is cost and launch capacity. There has to be a system that puts large structures of kilometers and thousands of tons into orbit. And upload them to geostationary orbit, that is, 36,000 kilometers away from the earth's surface. "We need very low-cost, high-speed, reusable launches (that can make more than one trip) to launch large amounts of material into space," adds Sanjay Vijendran. The space industry seems to be moving in this direction and is developing increasingly cheaper launchers, with greater payload capacity and reusable. The Starship system of the American company SpaceX seems to be one of the most promising. “That is why the interest in space solar energy has been aroused”, clarifies Abad. A point in space The option of locating the station at 36,000 kilometers has its reasons: there the solar panels would rotate to receive sunlight constantly. “It is the only point in space where things rotate at the same speed as the surface of the Earth. Here, the station will appear as a fixed point in space”, says Abad. At that great distance there will be no human being assembling and assembling large parts and with high precision to build the station. Robots will have to do it. And also the subsequent maintenance. This is another challenge. “We have taken a satellite into space capable of physically hooking up to another to transfer fuel and carry out correction maneuvers. What we have done so far is very basic robotics. Now we are talking about joining pieces for a structure of kilometric dimensions. And control it from the ground. In theory we know how to do it and we have experience controlling 100 meter satellites or the ISS. But control of a structure of kilometers has never been carried out, ”says Abad. How to transmit power to Earth wirelessly is another question he adds to the list. The panels would capture solar energy that would be transformed into electricity and transmitted to the earth's surface through a microwave beam. “It's a technology where the physics are well understood, but it hasn't yet been demonstrated over very long distances at high power levels. Until now, the most significant demonstrations (on Earth) that have been done are in the range of kW of power and the range of km of distance. This would have to be demonstrated gradually over longer distances and higher powers through more ground or airborne demonstrations and eventually through in-orbit demonstrations," explains Sanjay Vijendran. "It's absolutely possible," says Jean-Dominique Coste. "It's mostly," he continues, "a question of how we design the antennas and what specifications we decide on for the beam. The amount of power to be transferred, the frequency, the shape of the beam and the distance. To collect the energy on the ground, a huge rectifying antenna ('rectenna') is needed, capable of transforming the microwaves back into electricity to feed into the network. This requires installing antenna fields of tens of square kilometers. And here we must not forget the social component. “It is a challenge similar to the acceptance of nuclear power plants, oil and gas pipelines. Land will have to be reused, which can trigger social debates”, believes Jean-Dominique Coste. Reaching the technological maturity necessary to build a solar station in space requires political will and large public and private investments, as the reports received by ESA recommend. One of them suggests that the European Investment Bank (EIB) and the European Bank for Reconstruction and Development (EBRD) could be financial partners. It is estimated that a first base solar space station would cost 9,800 million euros and its maintenance around 3,500. "The financial effort is comparable to that of large-scale energy projects, such as large nuclear power plants, large offshore wind farms or large oil platforms," ​​says Jean-Dominique Coste. If we overcome all these challenges, we could have the first solar power station in space "within 10 to 15 years," estimates Sanjay Vijendran. it may interest you news No The first trip around the world from the perspective of the 21st century and space exploration news No This is the first European lightning 'chaser' news No NASA is considering September 23 or 27 for the third launch attempt de Artemis I For now, space-based solar energy is an incipient technology that, if developed, promises to become the star of the renewables mix.

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