| >solar panel is on-orbit, you get twice the solar energy - assuming that it is out of Earth's shadow Not quite. When compared to stationary panels (which beat trackers economically, so they should be the baseline), space-based power harvests π (yes, pi) times as much sunlight due to lack of cosine loss, plus there's the bonus of reduced reflective loss. Atmospheric and weather loss is avoided entirely. I would estimate 4-5x the energy. The big advantage of space-based solar imo is the ability to create giant collection areas defined by minutely pressurized helium structures. A giant parabolic mirror on Earth needs to fight gravity, winds, and the Earth's rotation (tracking). Similar concept: https://tec.grc.nasa.gov/past-projects/solar-concentrators/a... Launch a 30,000 m^2 concentrating collector in a single launch? It's only 12 MW, but it's constant (unlike ground-based solar at ~18% capacity factor), and it's deliverable anywhere in the world, or even to other satellites. What if microsatellites could summon extra power by POSTing an ephemeris to an endpoint? Is there a market there? It's an interesting niche tech, but spaceflight is just so expensive that I doubt it'll ever be viable. |
If you use them with solar panels, then your panel will heat up and its efficiency will drop. Maybe lifetime as well. If you use a thermoelectric generator, you then have wearing mechanical low efficiency systems on board.
In both cases you need to reject heat, which is hard in space.
They also require precise pointing.
There's also the problem of beaming the power to earth. If you're in low orbit, there would have to be lots of receiving stations and the power would be intermittent unless you had a big constellation. And all the problems with inclination and the spinning earth... If you're in geostationary orbit, your sending and receiving antennas would need to grow huge.
What about beaming between satellites? You'd need a laser for that. Maybe they're becoming quite small and efficient with modern semiconductor technology developed for military uses. Still the receiving end might have low efficiency.