[SunkenCiv]

IOW, no extra heating -- since the light converted in orbit would have been intercepted by the Earth anyway -- and actually cooling -- because the best available photovoltaics are only 30 per cent efficient.

[Wonder Warthog]

"...since the light converted in orbit would have been intercepted by the Earth anyway -- and actually cooling -- because the best available photovoltaics are only 30 per cent efficient."

Not quite true. Cooling would only occur if the "sunsats" were stationed between the earth and the sun. More than likely, they will not be so stationed, so the net effect WOULD be some slight heating of the planet, as the total energy would be that normally received from sunlight plus the added energy from the sunsats.