The European Space Agency wants solar panels in space, but will that work?

ESA Director Joseph Asbacher stated after several independent studies that the space agency should start work on a solar panel system in space. space solar energy, also called SBSP, bypasses some of the problems with solar panels on Earth. But there are critics, too. For example, Elon Musk has said that this is “the most stupid idea ever”. How does the principle work?

The European Space Agency wants to put huge satellites into orbit to collect solar energy and “send” it back to Earth. Solar panels work as you’d expect, but the energy is then converted into microwaves. This radiation is sent back to Earth, where solar panels or antennas capture the energy and convert it back into electricity. According to Aschbacher, in this way we can significantly address the climate problem.

Space solar panels have some potentially huge advantages over the panels on your roof. First of all, you don’t depend on the weather in space; There are no clouds to hinder your yield. In fact, you do not even depend on the day-night cycle, because ideally, the satellite is always pointed towards the sun. In addition, a lot of energy is lost in the Earth’s atmosphere. According to the European Space Agency, the density of the Sun in space is up to ten times that of the Earth’s surface.

With the Solaris programme, the European Space Agency aims to meet a quarter to a third of Europe’s electricity demand. Become According to Ars Technica About 3000 TWh of electricity is used annually in the European Union. So we are talking about a maximum required yield of about 1,000 TWh using space solar panels.

image via Andreas Triuer / European Space Agency

This is a huge requirement, at least because the satellites are huge. A single satellite of solar panels weighs 10 times the mass of the International Space Station. The space station was assembled piece by piece over ten years. The International Space Station weighs about 420 tons, so one solar panel weighs 4,200 tons. That’s an estimated 80 spaceship flights, for example from SpaceX. The European Space Agency wants to have up to fifty solar satellites in space. The Solaris project will cost hundreds of billions of euros. There are no unimportant details.

This is partly why Elon Musk mentions in the excerpt below: “If anyone wants space solar panels, it’s me. I have a rocket company and a solar panel company, I should love it. But it obviously won’t work. After all, it should be better.” of solar panels on Earth. You have up to twice the solar energy in space in theory. But you also have to convert twice. (…) What is the conversion efficiency?”

Musk states that photons from the sun are converted into electrons in solar panels. They then have to be converted back into photons (microwaves), until they are converted back into electrons on Earth. So it is likely that a lot of energy will be lost in the process.

The project is still in its infancy and details are not finalized yet. For example, it is not known what the conversion efficiency is. The parties involved will also have to agree to the ESA’s plan, assuming hundreds of billions of euros can be raised.

Sources:
ESA And the Joseph AschbacherAnd the via Ars Technica