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Most solar power satellite designs put the sat in geostationary, which simplifies things dramatically. It makes the power density low enough at ground level tha

Most solar power satellite designs put the sat in geostationary, which simplifies things dramatically. It makes the power density low enough at ground level that birds can fly through the beam without harm. The receiver has to be several square kilometers but it's mostly antenna wire. The transmitter would be a phased array antenna, and getting even that much focus would require a reference signal transmitted from the ground station.

walrus01 5y ago
In my opinion by the time you're going to the trouble to clear a flat plot of land and get into the construction project of erecting a several square km sized receiver array, you might as well just go whole-hog on commodity ground mount photovoltaics on the same area of land. And totally eliminate the cost of the satellite. There's plenty of contractors out there who specialize in building such things from existing COTS systems/subsystems and components. Look at the specifications and size of some of the large ground mount PV systems in China and India. Margins are very thin in this business and very competitive on $ per kWh feed-in tariff rates paid to contracted systems. The construction process has been optimized to nearly as good as it can get now. Labor is a major cost.
- DennisP 5y ago
  And add the cost of batteries.
  - walrus01 5y ago
    doesn't necessarily have to have batteries, as in many common installations, daytime PV is used to flatten the curve of fuel consumed by regional coal, gas, other fossil fuel power plants servicing the daytime peak of load demand. Conveniently enough in many places with hot weather when the peak of load demand is occurring mid afternoon with everybody's air conditioner running, the PV system is also performing at its best. Or can be connected to something long distance similar in tech to the pacific HVDC inter-tie to move power long distances to where it's needed, or can be used to pump water uphill in a nearby pumped-storage hydroelectric system.
    - DennisP 5y ago
      I mean yes, of course ground-based is cheaper if it's just part of a grid with lots of fossil power. I'm assuming we want to eliminate the fossil plants. For that, SPS at SpaceX Starship launch costs has a decent chance of being cheaper than ground-based solar plus the the various extra systems required to turn it into reliable power.

walrus01 5y ago

In my opinion by the time you're going to the trouble to clear a flat plot of land and get into the construction project of erecting a several square km sized receiver array, you might as well just go whole-hog on commodity ground mount photovoltaics on the same area of land. And totally eliminate the cost of the satellite. There's plenty of contractors out there who specialize in building such things from existing COTS systems/subsystems and components. Look at the specifications and size of some of the large ground mount PV systems in China and India. Margins are very thin in this business and very competitive on $ per kWh feed-in tariff rates paid to contracted systems. The construction process has been optimized to nearly as good as it can get now. Labor is a major cost.

DennisP 5y ago
And add the cost of batteries.
- walrus01 5y ago
  doesn't necessarily have to have batteries, as in many common installations, daytime PV is used to flatten the curve of fuel consumed by regional coal, gas, other fossil fuel power plants servicing the daytime peak of load demand. Conveniently enough in many places with hot weather when the peak of load demand is occurring mid afternoon with everybody's air conditioner running, the PV system is also performing at its best. Or can be connected to something long distance similar in tech to the pacific HVDC inter-tie to move power long distances to where it's needed, or can be used to pump water uphill in a nearby pumped-storage hydroelectric system.
  - DennisP 5y ago
    I mean yes, of course ground-based is cheaper if it's just part of a grid with lots of fossil power. I'm assuming we want to eliminate the fossil plants. For that, SPS at SpaceX Starship launch costs has a decent chance of being cheaper than ground-based solar plus the the various extra systems required to turn it into reliable power.