[owenversteeg]

The land use issue is the main reason why we still need moonshot research into things like fusion. As a species we have always been limited by the cost of energy. I was shocked when I learned that world energy consumption was ~13 exajoules in 1800, ~18 in 1820, ~75 in 1945, and ~550 in 2020. Energy consumption from the Founding Fathers to WW2 only rose by a factor of four!? We went from horses - 1800 was before the first steam train - to supersonic flight with only six times the energy!? And today, in the time of the hyperscalers, we use only 30x the energy of 200 years ago!

With solar I doubt we will see costs well under, say, a half cent per kWh. Even when the land and panels are ~free, the surface area of that much aluminum/glass/wiring/infrastructure has a cost. And a half cent is cheap, but not too cheap to meter. You could get a barrel of oil in the late 1800s for ~$20 of today's money, roughly 1 cent/kWh of thermal energy or 3 cents if you run it in today's plants to make electricity. The idea that a _time machine to the 1800s_ would be a cost-effective way to obtain energy is patently absurd and I suspect the man with a handlebar mustache who would sell you the energy would think it similarly absurd; it certainly isn't true for any other serious industrial input. But energy is unique.

At 0.5 cents you're not going to scale global energy use by orders of magnitude. And if you want any of the various promised sci-fi scenarios (flying cars, large scale high speed travel, scaled up space travel, true recycling) you need orders of magnitude more energy.

Don't get me wrong, solar is a great solution for today. But I don't think it's the solution for the future that many people dream of.

[dTal]

I have the opposite reaction to your historical energy figures - energy consumption is clearly not as important to technological progress as we imagine. If there's only a 4x difference between the Founding Fathers and B29s carrying nukes, why should there be orders of magnitude between today and [insert scifi]?

No, the real question is, where the hell is this exponential increase coming from? I think anyone would agree that, along most obvious metrics, the difference between 1800 and 1945 is much more pronounced than between 1945 and 2020. Yet the first was a 4x increase, and the second, over 7x. And in a third the time, too.

I'd like to see it broken down by country. I'll bet a lot of the increase actually comes from very poor countries turning into rich ones. In the west, our at-home per-capita energy use has not changed much from 1945 - may even have declined for some demographics (1945 houses were poorly insulated). But China lifted some hundreds of millions of peasant farmers into a middle class existence. That's got to be a bigger factor than the fact that I own a laptop and my grandpa didn't.

[owenversteeg]

>I have the opposite reaction to your historical energy figures - energy consumption is clearly not as important to technological progress as we imagine. If there's only a 4x difference between the Founding Fathers and B29s carrying nukes, why should there be orders of magnitude between today and [insert scifi]?

That's an interesting perspective, thank you.

As far as country breakdowns, a decent start is (as usual) Our World in Data. And indeed, as you expected, the increase in energy use is mainly from Asia. I think things are a bit more complex, though; most of China's energy use is in manufacturing. https://ourworldindata.org/energy-production-consumption

To your question, why do we need energy too cheap to meter? Well... because there are a lot of sci-fi scenarios that would need it. Any of (high speed travel / flying cars / space travel) at a large scale would use an unimaginable amount of energy. Plenty of ideas to protect the environment - true recycling, cleaning the oceans, truly cleaning wastewater from all the pollutants we put in it, et cetera all require far cheaper electricity. And the thing is that in most future-planning scenarios, if you need cheaper X, just wait. Most things get much cheaper over time! Not energy! If we want cheaper energy, we need to do something serious towards it, such as fusion - at least, I'm not aware of any realistic proposals to generate energy too-cheap-to-meter aside from fusion.