Space – Based Solar Power Station: What is it and Why It Can Be Dangerous for Humans?
David Faiman (Israel), the Global Energy Prize International Award Committee member, Professor of the Ben-Gurion University of the Negev.
Generating electric power from the Sun in space in an earth orbiting satellite is a very exciting prospect. There are three reasons for this. First of all, because there is no atmosphere to dilute the sun’s rays, the satellite actually sees sunlight about 50% stronger than earthbound solar panels would see it. Secondly, satellite sees the Sun for 24 hours a day except for the few minutes every day when the Earth passes between the panels and the Sun. And thirdly, what the satellite generates really is constant, because there's no sunrise and sunset in space and no clouds to make the output stronger and weaker and stronger and weaker every time clouds pass. So, this is very exciting. However, there are a number of challenges that have to be solved. One of them is that the solar electricity, which is generated in space, has to be converted into microwaves and that conversion is not a hundred percent efficient. And the microwaves when they reach the ground have to be converted back into electricity, that's also not a hundred percent efficient. So, there is a lot of quite a challenge to make the conversion process as efficient as possible. Secondly, there is the question of making sure that no aircraft accidentally fly through the microwave beam because it's very very powerful, much more powerful than a microwave oven at home. And, finally, one has to employ some kind of completely failsafe mechanism so that if the satellite is hit for example by a passing meteorite the microwave beam doesn't spill off and into some dangerous place where there are humans. So, these challenges have to be overcome. So ultimately, the question of whether we can have some satellite space electricity is a question of economics. Whether the economics of solving these challenges together with the cost of launching such a satellite into space can overcome the cost of constructing a simple array of solar panels on earth. But if this is actually going to be done I think it's exciting and useful because much can be learned from a small-scale experiment in terms of figuring out what the economics of a really full size project would be. So, I'm all in favor of it.