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> cost of getting a PV array into orbit is very expensive Musk will find a way. Another stepping stone to Mars.

ben_w 4y ago
It would be great on Mars. Mars has planet-wide dust storms. But for Earth, even if it was free to put the PV in Earth orbit, the ground stations need to have an incredibly low total cost to make sense. I can't remember how low exactly.
- DennisP 4y ago
  The ground stations are basically just antenna wire. For a large plant they would contribute just 0.7 cents/kWh to the total cost, according to the book The Case for Space Solar Power.
  - ben_w 4y ago
    Also needs a microwave frequency rectifier, plus installation costs are non-trivial as evidenced by the difference between the cost/W of a PV cell and a PV farm. Also, cheapest ground-based PV in the world is 1.04¢/kWh (Saudi Arabia), and the cheapest in the USA is 1.50¢/kWh (New Mexico), so 0.7¢/kWh is already a large percentage. https://commercialsolarguy.com/lowest-solar-power-prices-in-the-world/ https://commercialsolarguy.com/lowest-solar-power-prices-in-...
    - DennisP 4y ago
      Just to clarify, the 0.7 cents is total ground station cost, according to my source. At ideal locations, ground solar is super cheap, but the microwave receiver works anywhere. Not needing storage is a big difference, too.
      - ben_w 4y ago
        That seems a bit optimistic, but I don't have the book, so OK. (I really should get around to blogging what I think is wrong with this whole approach to space solar, where it works despite that, and how to improve on it for Earth usage; it comes up here every so often, and linking to my blog is easier than disjointed comments without images).
SyzygistSix 4y ago
He's talked about the idea, how much the two aspects - solar power and space - are things that excite him, and how it just is not a viable idea.
- DennisP 4y ago
  He made one comment, a decade ago, well before he started talking about $35/kg to orbit with Starship. In response to his famous question "what's the conversion rate," the answer is about 50%, according to the book The Case for Space Solar Power. That's not bad considering a panel in geostationary collects five times as much energy in 24 hours as a panel on Earth.

It would be great on Mars. Mars has planet-wide dust storms. But for Earth, even if it was free to put the PV in Earth orbit, the ground stations need to have an incredibly low total cost to make sense. I can't remember how low exactly.

DennisP 4y ago
The ground stations are basically just antenna wire. For a large plant they would contribute just 0.7 cents/kWh to the total cost, according to the book The Case for Space Solar Power.
- ben_w 4y ago
  Also needs a microwave frequency rectifier, plus installation costs are non-trivial as evidenced by the difference between the cost/W of a PV cell and a PV farm. Also, cheapest ground-based PV in the world is 1.04¢/kWh (Saudi Arabia), and the cheapest in the USA is 1.50¢/kWh (New Mexico), so 0.7¢/kWh is already a large percentage. https://commercialsolarguy.com/lowest-solar-power-prices-in-the-world/ https://commercialsolarguy.com/lowest-solar-power-prices-in-...
  - DennisP 4y ago
    Just to clarify, the 0.7 cents is total ground station cost, according to my source. At ideal locations, ground solar is super cheap, but the microwave receiver works anywhere. Not needing storage is a big difference, too.
    - ben_w 4y ago
      That seems a bit optimistic, but I don't have the book, so OK. (I really should get around to blogging what I think is wrong with this whole approach to space solar, where it works despite that, and how to improve on it for Earth usage; it comes up here every so often, and linking to my blog is easier than disjointed comments without images).

SyzygistSix 4y ago

He's talked about the idea, how much the two aspects - solar power and space - are things that excite him, and how it just is not a viable idea.

DennisP 4y ago
He made one comment, a decade ago, well before he started talking about $35/kg to orbit with Starship. In response to his famous question "what's the conversion rate," the answer is about 50%, according to the book The Case for Space Solar Power. That's not bad considering a panel in geostationary collects five times as much energy in 24 hours as a panel on Earth.