There will never be orbital PV plant that beams down any substantial amount of energy from space down to Earth.
- Let’s assume for a moment that you could collect 1 GW of power with the plant in orbit. Who do you think will allow any state on this planet to put a 1 GW microwave gun into orbit where it can target almost any place on Earth?
- Even if you trust your government, computers will control the process. How long will it take for hackers to nuke a city by redirecting the beam?
- A 1 GW plant is a joke; China alone had 392 GW installed at the end of 2022.
- Getting the material into orbit will be very expensive, even when SpaceX brings down the price some more. For the same price, you will be able to build a power plant on the ground that is several times bigger. So it’s not economical.
- The beam will target a receptor on the ground. If you live far away from that place, no power for you.
- This receptor will be huge (10 km diameter or more). If you hate huge, ugly structures like PV plants on the ground, this won’t work for you, either.
- Space in space is more limited than you think.
- If you put the solar panels in an orbit around Earth, they will sometimes be in the shadows of Earth or the Moon (and not working during those times) OR
- you need to give them engines (which need fuel that you have to send up for $$$) plus the structure will need to be much more sturdy (= $$) OR
- you must put it at one of the five Lagrange Points where it will take up so much space that you can’t do anything else there AND that means the ground station will rotate away from you so you can’t send energy down all the time; you could send the energy to several ground stations but those would have to be in different countries. See also: point 5.
- Point 6 means that we can only put up a few plants, maybe only a single one. So every other nation will object.
- Beaming energy down means converting the electric energy to microwaves. You have pretty big losses when that happens and you need to do the opposite on the ground, so you lose not x% but 2 * x% of the collected power. Which means you can again build a bigger plant on the ground for the same money.
- PV power plants need maintenance, even in space. So you need a crew. Which means living quarters, life support, lots of rockets going there with supplies and fresh crew. This will be very expensive, if if you pay the minimum wage of … probably $100 / hour? You need trained astronauts for this or you’ll risk that your plant will be broken a lot of times because the crew killed itself.
- This thing will be huge (maybe 10 square kilometers). No one has ever built a structure of this size in space. It’s not technically impossible, just expensive. There will be several failed attempts which someone will have to dismantle before you can start again because you simply can’t afford a 1 km2 piece of junk floating next to your plant waiting to crash into something important.
- If this structure collapses, it will generate a huge cloud of debris, possibly triggering the Kessler syndrome
- The atmosphere is reducing the power of PV on the ground a bit but it’s just a few percent. The biggest problem on the ground is dust and rain. That’s the only feature where a space based PV plant is better.
- After a few years, you will have to decommission the plant. That means many rockets to bring all the junk back down to Earth. It will also leave a lot of small junk behind which will poison the space for anything else for centuries.
In the end, the small advantages don’t make up the for the huge costs, military security risks. It’s much cheaper to build huge PV plants on the ground, using cheap labor and materials which can be delivered by truck.
That’s why I’m convinced an orbital PV plant is a nice dream but it will stay a dream. It’s okay as a thought experiment but it can’t solve any pressing or important problems. There are solutions that are much more realistic and cheaper, for example PV plants in deserts where you plant grass in the shadow of the panels to cool the panels and turn the desert green again.
Yeah, they are a bit ugly on the ground but if that is a killer for you, either stop using electricity or live with it. No orbital PV plant will make a noticable difference here during your entire lifetime.
See also: Space-based solar power
