There are good reasons to generate solar power in space. For one, you’re closer to the sun, so the energy yield is better. And the sun never sets. It’s a 24-hour solar resource in the upper orbit. The question, really, isn’t whether solar-in-space is a good idea. It is. It’s whether the idea is feasible and cheap enough.
As we’ve seen before, there have been several efforts, most notably in Japan. The Japan Aerospace Exploration Agency (JAXA) has sketched out a 20-year development roadmap, with the aim of deploying a 1 gigawatt system in the 2030s. Weighing about 10,000 metric tons and measuring several miles across, it would float in space and transmit power to Earth in precise microwaves. Fields of receiving antennae would be a stationed on an island, say outside Tokyo, from where the power could be transferred to where it’s needed.
It sounds futuristic, but JAXA continues to make breakthroughs, indicating the idea might eventually be possible. Recently, it announced it had sent 1.8 kilowatts over a distance of 170 feet. “This was the first time anyone has managed to send a high output of nearly 2 kilowatts of electric power via microwaves to a small target, using a delicate directivity control device,” a JAXA spokesperson told AFP.
Separately, Mitsubishi Heavy Industries said it had sent 10 kilowatts 1,600 feet, illuminating LED lights at the other end. MHI is aiming for a 400 MW satellite by 2030–a plant capable of supplying about 150,000 homes during peak time. But wireless power transmission could have many other uses as well, as an MHI press release says. “The achievement of wireless power transmission over long distances will not only facilitate the transmission of power to locations where installation of power cables has been difficult or dangerous; it is also expected to contribute to transmission of power from offshore wind turbines and various other applications in the future.”
In 2011, a report from the International Academy of Astronautics looked at three designs, and concluded: “Solar Power Satellites appear to be technically feasible as soon as the coming 10 to 20 years using technologies existing now in the laboratory.” It seems that solar from space is on track, though, as ever, the cost will be key to its success. One argument against its deployment: earthbound solar, though less bountiful, is likely to be much cheaper two decades from now.