It’s a wild idea, but scientist John Mankins believes technology has advanced to the point where we can harvest solar power in space and use microwaves to beam the electricity back to Earth.
Mankins, now president of consulting firm Artemis Innovation and former head of NASA’s Advanced Concepts Studies, completed a detailed feasibility report on Solar Power Satellite via Arbitrarily Large Phased Array – SPS-ALPHA.
“The vision of delivering solar power to Earth from platforms in space has been known for decades. However, early architectures to accomplish this vision were technically complex and unlikely to prove economically viable,” Mankins wrote in the abstract to his report. “Ten years ago a number of key technical and economic uncertainties remained. A new SPS concept has been proposed that resolves many, if not all, of those uncertainties.”
The structure Mankins envisions working is “Biologically inspired architecture, analogous to a hive of bees or a colony of ants.”
The idea behind the concept is that electricity collected in space could be beamed to the world’s most remote off-grid areas. Military troops could use it in the field and it would be accessible almost anywhere.
Mankins reports that it is feasible and also economically realistic to use solar panels to collect energy in space and send that power via satellite to Earth.
“SPS-ALPHA, when incorporating selected advances in key component technologies, should be capable of delivering power at a levelized cost of electricity of approximately 9 cents per kilowatt hour.”
At that price, electricity beamed from space could be cheaper than utility grid power almost anywhere.
Of course, Mankins' report is only a feasibility study in the earliest stages of development. He estimates that it will take 15 years and $50 million to complete two small-scale prototypes and another decade and $3 to $4 billion to get a large functional prototype into space.
Mankins said he expects the power would be most useful in geographically isolated areas where electricity is the most expensive. It could also be used as an emergency power source in disaster situations since satellites can be turned in any direction and power could be beamed to specific locations on command.
The power would have to be delivered to some kind of receptor on the ground, however, and the receptors would have to stretch five to 10 kilometers so the electricity could be dispersed enough to prevent danger to people. That could pose a problem, though Mankins added the receptors could be made of thin film that would allow sunlight and rainwater to pass through and vegetation on the ground to thrive.
“Although no breakthroughs in technology appear to be needed to realize SPS-ALPHA, transformational changes in how space systems are designed are needed,” Mankins concluded. “Additional research and development will be required for confirmation of this very promising finding.”