Peak_Yeast wrote:I use a combination of solarcells and solarheaters.
I have vacuum solarheaters for the water and some heating - and a large storage tank.
I have air solarheaters built on the outside of the southern wall.
The solarcells are, of course, to run the computers, the cooker, the lights, the electric car and so forth.
Solarcells has been produced with efficiencies upto about 45% they may become the norm in the future. Just like we started with A-Si or Mono-Si with 10%. Besides a low efficiency is NO PROBLEM unless of course, you live in a very space restricted area. Roof tops are almost always clear space... On the hourse, the garage or outhouse.
For that same area you could grow plants, or whatever. Its just more effort.
Humans consume 10mwh per year just to survive. The Sahara produces 4mwh per square meter, which should allow a density of 400,000 people per mile.
However, after various losses that's really 4,000, and plants usually have 100 kwh energy after sitting on a square meter for a year. That's 99% loss. Even if you powered the Sahara on solar it would only support 40 people per square mile. And considering shelter it would come down to a few people per square mile, which it already has.
So placing solar in farmland will obviously just reduce the crop yield of whatever is growing there, and even in barren desert it produces little to no food vs what's already there.
Covering 10% the entire Sahara in panels would produce 1e18 watthours, or roughly the entire global energy supply. However, there are 2 billion trees in the sahara containing 1e16 wh of energy. These are just rough numbers but it's still a lot of waste to put panels.