Physics World: Space-based solar power: could beaming sunlight back to Earth meet our energy needs?S

The notion of capturing sunlight in space and beaming it to Earth has long been the stuff of science fiction. But as Jon Cartwright discovers, governments around the world are now taking “space-based solar power” seriously as a potential solution to our energy needs.

The theoretical physicist Freeman Dyson once imagined an alien civilization that was so advanced that it had surrounded its parent star with a giant, artificial shell. The inner surface of this “Dyson sphere” would capture solar radiation and transfer it towards collection points, where it would be converted into usable energy. Such a notion remains science fiction, but could a similar principle be used at a much smaller scale to harness the power of our own Sun?

After all, beyond the clouds, in the nightless blaze of near-Earth space, there is more uninterrupted solar power than humanity could realistically require for centuries to come. That’s why a group of scientists and engineers has, for more than 50 years, been dreaming up techniques to capture this energy in space and beam it back to ground.

“Space-based solar power”, as it’s known, has two huge benefits over traditional methods for tapping into the Sun and the wind. First, putting a sunlight-capturing satellite in space means we wouldn’t need to cover vast swathes of land on Earth with solar panels and wind farms. Second, we’d have an ample supply of energy even when, despite local weather conditions, it’s overcast or the wind has petered out.

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