It seems to me the assumption that energy consumption per person has peaked at the current European level and not increase in 100 years wildly false. Compelling new uses for energy will be found and other cultures are less likely, I think, to restrict personal energy consumption as much as Europe does currently.
That might be true, but remember that MacKay's numbers assume 100% non-renewable energy. In reality, solar panel prices are dropping fast, and they'll likely make up a substantial portion of the energy supply. Solar energy captured with photovoltaic panels is solar energy that's not heating the earth directly, so the waste heat problem is much smaller. The same is true for all renewable sources, e.g. winds and tides heat the earth uselessly if we don't capture them.
I agree. Keep power production on Earth to like 50% solar (wind, sunlight, tidal, etc) and there will be no problem with this heat issue. Bezos has specifically stated that he hopes to put industrial production off earth to avoid the industrial heat production problem in the far future.
