Digest Number 509

You're not getting me; I'm saying for laser power beaming between L1 and the lunar surface for example, the worst PV you can find can give you 50% efficiency, under a dollar per watt or so, including the laser and PV. And you can use direct sunlight when it's available as well.

Microwave is great for returning power to earth, because it punches through the clouds, but there's no weather on the moon, and so it's going to be more expensive by the time you've laid out multiple square kilometers of rectenna. I mean, microwaves don't focus down worth a damn from any distance unless you have huge antenna at each end. Light is easy.