The costs of space solar compared to terrestrial solar are just absurd, and unless we are talking about some sort of https://en.wikipedia.org/wiki/Kardashev_sca

The costs of space solar compared to terrestrial solar are just absurd, and unless we are talking about some sort of https://en.wikipedia.org/wiki/Kardashev_scale https://en.wikipedia.org/wiki/Kardashev_scale science fiction, it makes no sense whatsoever. The area required for ground-based solar to produce enough power for all of humanity (~20 TW average currently, ~400k km2) is about 20% of already-built urban area (~2 M km2.) Solar is distributed right to where you want to use it for the most part too. Industrial solar is approaching $1 per watt installed, and GDP of the top-ten nations combined is around $60T. Spread over 20 years, to install enough solar to meet all world energy needs would require ~1-2% of GDP per year, a lot but definitely doable (less than what the world spends on "defense", ~$2T/yr.) And this overestimates the cost, as at this scale costs will come down and GDP is still increasing. This also overbuilds solar as we still have other sources of clean power (and even, say, 75% reduction of fossil fuel use would give us plenty of time to figure out the rest.) So, in summary, lifting solar panels to space to bring energy to Earth is close to the dumbest thing I've ever heard.