I’ve been wondering this morning what will power the world not just in 100 years time, but in 1000 years time.
I don’t think we’ll be using coal or oil or gas in 1000 years time, because there’ll quite likely be none left. And I don’t think we’ll be using wind farms and solar farms and hydroelectric power either, if only because it’s horribly inefficient, and we’ll need the land for something else. Nuclear? I doubt that too. Too many Fukushimas and Chernobyls.
No, I think that in 1000 years, all our energy needs will be supplied by solar collectors in earth proximity orbits. And there’ll be an almost unlimited supply.
The Solar Constant – the amount of solar power per square metre at the orbit of the Earth – is about 1362 Watts/square metre. Currently, nuclear power stations supply something like 2700 TWh (terawatt hours) of electric power, about 30% of the Earth’s energy consumption. Assuming (a little optimistically) that an orbiting solar collector can convert 1388 Watts into a kilowatt of electric power per square metre, then a square kilometre could generate a million kilowatts of power, all day every day. That’s 8.76 TWh per year. And all you’d need to match the Earth’s current total nuclear power production would be about 285 square kilometres of solar collectors, in a 17 km by 17 km square – about the size of a city. And with 3 or 4 of them, you could meet the entire world’s current energy requirements, all beamed down to the surface at remote islands where nobody could get fried. And it would all be “sustainable” for as long as the Sun kept shining.
All the old power stations would be closed down. There’d be no wind farms or terrestrial solar farms or hydroelectric power stations. Everyone would have almost unlimited amounts of power available to them, almost (but not quite) free. All transportation would be electric, including air travel. People would go everywhere by air, including visiting their next door neighbours.
So roads would vanish. And ports would vanish. And railways would vanish. The Suez canal and the Panama canal would fall into disuse. Everything would get slowly covered in grass and then in dense forests, with natural streams and rivers flowing through them. The Greens would love it.
Most people would be working part-time somewhere in outer space. They’d have jobs servicing the huge solar collectors that were out there. The Earth would be their holiday home.
One thing that slightly worries me about all this is that, with the Earth overdue for the start of the next ice age, our current, entirely benign, CO2-driven global warming may not be enough to prevent it happening. And yet my prediction above is that we will have stopped generating CO2 in few decades or centuries time. And if we don’t warm up the world some other way, we’ll find ourselves in a new ice age. Would we be able to get enough power from orbiting solar collectors to not only meet the energy requirements of everyone on the planet, but enough to keep the whole planet warm as well?
I might be able to adapt my terrestrial heat flow model to find out how much energy would be needed to stave off a new ice age.
But here I’m heretically worrying not so much about global warming as global cooling. I think a new ice age would be far, far worse than almost any amount of global warming, if only because global warming is very slow, and ice ages can start almost overnight. I think if Greta Thunberg had any sense (she doesn’t) she’d be more worried about a new ice age, particularly given that she lives in Sweden, which would be one of the first places hit.