Comment by mlindner
6 hours ago
It's always better to generate electricity on the ground than attempt to beam it to the ground from space. The efficiency loss of beamed power is huge.
6 hours ago
It's always better to generate electricity on the ground than attempt to beam it to the ground from space. The efficiency loss of beamed power is huge.
The efficiency loss of nighttime is approximately 100% if we’re talking about solar energy. At least at a most basic level, it’s not totally absurd to stick some kind of power beaming contraption in space where it is mostly not shadowed by the Earth and beam power to a ground station.
I concur it’s not necessarily totally absurd — but when you consider that such contraptions require large — very large! — receiving arrays to be built on the ground, it’s hard to avoid concluding that building gigantic photovoltaic arrays in, say Arizona (for the US) along with batteries for overnight buffering and transmission lines would still be massively more efficient.
Is that more or less absurd than making deals with our neighbours to share their electricity? Build some solar farms around the planet and then distribute it over wire.
I honestly don't know the answer. I know there's some efficiency loss running over long wires too but I don't know what's more realistic.
In theory you can do HVDC over long distances. In practice that doesn't help much. Power would normally want to run north to south (not gonna do HVDC across the oceans anytime soon), and so the terminator hits you at the same time everywhere. It's got to be batteries if you want PV at scale.
The practical difficulties aren't really long distance transmission though. They're political and engineering. Spain had a massive blackout recently because a PV farm in the south west developed a timing glitch and they couldn't control the grid frequency - that nearly took out all of Europe and the power wasn't even being transmitted long distance! The level of trust you need to build a giant integrated continent-wide power grid is off the charts and it's not clear it's sustainable over the long run. E.g. the EU threatened to cut Britain's electricity supplies during Brexit as a negotiating tactic and that wasn't even war.
There is absolutely nothing realistic about power transmission from space to earth, wired or wireless.
We have these things called batteries, you charge them during the day, and drain them at night.
A solar+battery setup is already cheaper than a new gas plant. Beaming power from space is absolutely asinine, quite frankly. The losses are absurd, the sun already does it 24/7, and we know how to make wires and batteries to shuffle the sun's power around however we need to. Why on earth would we involve satellites?