Could solar panels in orbit power the Earth?
The notion of space-based solar power actually dates back to the 1970s oil crisis. It was set aside after oil prices went back down, but since then, two things have happened: One, the world has become a lot more desperate to solve climate change; and two, technological innovations have brought this crazy idea out again.
The idea is gaining attention, and with some big investments, it's possible that space-based solar power could become a reality within a few decades.
Of all the energy sources available to us Earthlings, the sun is pretty much as good as it gets, says Lewis-Weber. "As Elon Musk has stated, we have a fusion reactor in our sky."
The problem with regular solar power is that the sun isn't always up. We have nights, and cloudy days. The panels also take up a lot of land.
"To power entire world with solar power, we would need to cover an area that's 92 percent the size of Nevada in solar panels, and that's not even counting the batteries," says Lewis-Weber. "To me, that's just not feasible."
But if you were to put those same solar panels in space, high above the atmosphere, there would be no weather to contend with, and the panels would experience nearly constant sunlight. Plus, the light that reaches them would be 27 percent brighter, since it wouldn't need to filter through the atmosphere.
These solar panels would use microwaves to beam power back to receivers on Earth. And in case you're worried, those microwaves wouldn't fry us.
"The system would be designed not to exceed safe power densities," Paul Jaffe, who works on space-based solar panels at the U.S. Naval Research Lab, told us. (Jaffe has proposed a plan to launch solar panels into space from Earth "It's sort of like how you don't have to worry about breaking the land speed record by riding your bike. The system couldn't be weaponized."
Nor would the large array cast a shadow over the Earth. Sunlight would diffuse around the structure, like it does for other satellites in orbit. Even when the moon eclipses the sun, it only casts a shadow over a small part of the world for a short period of time. The shadow from an array the size of Nevada would be "not even a millionth of that," says Jaffe.
There's another advantage to space-based solar power. These arrays could beam power down across vast portions of the globe, wherever the receivers are set up. That opens up the possibility of sending electricity to villages in developing countries, or to disaster-stricken areas. The receiving equipment, Jaffe says, could fit into a couple of shipping containers.
Plus, since the sunlight would be essentially continuous, space-based solar power doesn't require the development of large batteries to store the power--something that holds back ground-based solar power.
There's just one big problem: It's going to take a LOT of solar panels to power the world, and launching all of those up into space will not be cheap. Just one SpaceX launch costs about $60 million, and that's much cheaper than the competition. In the paper, Lewis-Weber calculates that it could cost tens of trillions of dollars to send up a meaningful number of solar power satellites.
"Definitely the launch cost is one of the most influential factors in determining the cost of space solar," Jaffe agrees. "Without that cost coming down, or using some alternate means to put the spacecraft in place, it's not going to compete [with fossil fuels] on price."