Do you remember the Microwave Power Plant in Sim City 2000? The idea behind them was an intriguing one, you launched a satellite into orbit with a massive solar array attached and then beamed the power back down to Earth using microwaves that were collected at a giant receiver. Whilst it worked great most of the time there was always the risk that the beam would stray from its target and begin setting fire to your town indiscriminately, something which the then 11 year old me thought was particularly hilarious. Whilst we’ve yet to see that idea (or the disasters that came along with it, but more on that in a moment) the idea of putting massive solar arrays in orbit, or on a nearby heavenly body, are attractive enough to have warranted significant study.
The one limiting factor of most satellite based designs though is that they can’t produce power constantly due to them getting occluded for almost half their orbital period by Earth. Shimizu Corporation’s idea solves this issue in the most fantastical way possible: by wrapping our moon in a wide band of solar panels, enabling it to generate power constantly and beam it back down to Earth. Such an endeavour would seem like so much vapourware coming from anyone else but Shimizu is one of Japan’s leading architectural and engineering firms with annual sales of $14 billion. If there’s anyone who could make this happen it’s them and it aligns with some of the more aggressive goals for space that the Japanese government has heavily invested in of late.
The idea is actually quite similar to that of its incarnation in Sim City. Since the Moon is tidally locked with Earth (I.E. one side of the moon always points towards us) there only needs to be a single base station on the moon. Then a ring of solar panels would then be constructed all the way around the Moon, ensuring that no matter what the position of Moon, Earth and the Sun there will always be an illuminated section. There would have to be multiple base stations on Earth to receive the constantly transmitted power but since the power beams would be pointable they needn’t be placed in any particular location.
Of course such an idea begs the question as to what would happen should the beam be misaligned or temporarily swing out of alignment, potentially roasting anything in the nearby vicinity. For microwaves this isn’t much of a threat since the amount of power delivered per square meter is relatively low with a concentrated burst of 2 seconds barely enough to raise your body temperature by a couple degrees. A deliberately mistargeted beam could do some damage if left unchecked but you could also combat it very easily by just putting up reflectors or the rectilinear antennas to absorb it. The laser beams on the other hand are designed to be “high density” so you’d want some rigorous safety systems in place to make sure they didn’t stray far from the course.
Undertaking such a feat would require several leaps in technology, not least of which would be in the automation of its construction, but it’s all based on sound scientific principles. It’s unlikely that we’ll even see the beginnings of something like this within the next couple decades but as our demand for power grows options like this start to look a lot more viable. I hope Shimizu pursues the idea further as they definitely have the resources and know how to make it happen, it’s all a question of desire and commitment to the idea.