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Comment by danjayh | Hacker News Reader

Fusion power is already here, in the form of solar. The reactor is just not located on our planet. I think storage of the sun's fusion power is probably an easier problem to solve than actual fusion, and I think that very shortly the economics will become compelling enough that it will happen without the government spending billions of dollars of OPM (Other People's Money) to do it. Any utility that can feasibly cut the cost of its fuel input to 0 with a reasonable capital expense would be insane not to do so, and I think that capital expense for this is in the process of crossing the 'reasonable' line in many areas of the planet.

(Sadly, in my native eternally cloudy West Michigan, the payback on a solar array is still "maybe never")

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Solar energy is the very-long-term future of energy in the "Dyson sphere" sense, but it's hard to efficiently extract solar power on the surface of the Earth. It's significantly easier than it was, but even the theoretical incoming solar energy within a country the size of, say, Britain wouldn't be sufficient to maintain their current standard of living. Fusion could deliver a world-changing, post-scarcity level of energy compared to our current energy usage requirements.

You could get similar results from solar by collecting it in space and transporting the energy to Earth somehow (either by direct beaming or by shipping down some sort of refined chemical fuel). But that's just the beginning of the process of building a Dyson Sphere.

I think your calculation is a little pessimistic: even if we include all sorts of things that today aren't powered from electrical generators, 200,000TWh is plenty to power the whole world for a year. Assuming 8 hours of sunlight per day of 200 watts per square metre (not an unreasonable figure), that's "only" an area of ~400 square kilometres (assuming I haven't dropped a zero somewhere).

That would be difficult but not impossible to fit in Britain.

This of course ignores problems of storage, inconstancy of supply and so on, but there's no problem with total capacity that means we cannot maintain a standard of living way above what we experience today.

Remember to include non-electrical energy use too. Many kWh of oil, coal, and natural gas are used in the UK, for industry, transport and building heating.

To make matters worse, also keep in mind the energy cost of closed-loop synthesis of jet fuel from atmospheric and oceanic sources. (Yes, you can turn CO2 and H20 back into hydrocarbons with solar power, but it's considerably more expensive than just drilling the hydrocarbons out of the Earth's crust.)

Admittedly dated, but this is my primary source: https://www.withouthotair.com/

The summary was essentially that, even theoretically, Britain is not capable of energy self-sufficiency for their current standard of living based on renewable power sources in Britain itself. Though it was close enough that the necessary reductions in consumption are attainable.

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