> There aren’t gates of Hell just anywhere. A kilometre below ground in Kamchatka is considerably hotter than a kilometre below ground in Kansas. There is also readily accessible geothermal energy in Kenya (where it provides almost fifty per cent of the country’s energy), New Zealand (about twenty per cent), and the Philippines (about fifteen per cent)—all volcanic areas along tectonic rifts. But in less Hadean landscapes the costs and uncertainties of drilling deep in search of sufficient heat have curtailed development.
It's also quite hard to find suitably hot rocks suitably close to the surface.
Focusing on fusion .. I think that's a legacy of 60s SF, when the fission revolution was still promising "energy too cheap to meter".
I like how David Hamel put it: We live in this thin sliver on the surface of the planet where it is reasonably peaceful. This is the tranquility! It's a good thing! If you go up or down by a mere few miles there is so much energy it kills you.
https://www.withouthotair.com/c16/page_96.shtml
The problems are that rock isn't a good conductor of heat, so once you've cooled a bit down, you have to wait for it to warm up. Warming only happens very slowly at the rate of < 50mW / m² which limits the amount of power you can get out.
The worst earthquake that was induced that way was 3.5, but given that one of the quakes happened in an area that had a catastrophic earthquake in the Middle Ages, some caution might be warranted: https://en.wikipedia.org/wiki/1356_Basel_earthquake
Ground-source heat pumps extract about 1000 times more power from ground loops, where does the difference come from?
In a world where anyone could just YOLO any reactor into production with minimal red tape, consequences be damned, fission energy would actually be extremely cheap. Hence the optimism around fusion. The promise of fusion is an actualization of last century's idealistic conception of fission. It can be a silver bullet for all intents and purposes, at least once it's established with a mature supply chain.
If economically viable fusion was "cracked" what would the nature of it's unreliability even be?
Since you're comparing it to nuclear, I'm assuming you mean electricity production here, not energy production?
It's always worth remembering that electricity only accounts for ~20% of global energy consumption (in the US it's closer to 33%).
I suspect people confuse these two because in a residential context electricity plays a huge part of our energy usage, but as a whole it's a smaller part of total energy usage than most people imagine.
But any serious discussion of renewable energy should be careful not to make this very significant error.
The Lawrence Livermore National Laboratory publishes a great diagram of US energy use: https://flowcharts.llnl.gov/sites/flowcharts/files/2024-12/e...
At worst, nuclear waste contaminates a discrete section of the Earth. Climate change affects literally everywhere. The correct answer would have been to aggressively roll out fission power 40-50 years ago and then pursue renewables. You can argue that other solutions would make fission power obsolete, but we would have been in a much better spot if it'd at least been a stepping stone off fossil fuels. Instead, we have 40-50 years of shrieking and FUD from environmentalists over an issue that can be kept under control with proper regulation. The US Navy has operated reactors for over 60 years without incident, proving it can be done with proper oversight.
TL;DR nuclear has issues, but I'd take it over coal every day and twice on Sundays, at least until something better can scale.
I wasn't really commenting on the merits of 20th century environmentalist movements, more raising the general point that fission power has inherent costs which weren't reflected by narrow 1950s analyses of how much energy was extractable from U-235. Operation of a fission plant requires much more capex and opex than it would if we didn't care about cleanliness (waste management), security (fissile material theft prevention), or safety (meltdown prevention).
Fusion power is more complex to invent and practically depends on modern technologies that didn't exist 50 years ago, but once the first demonstration plants are operational, marginal costs to deploy and operate more should be much lower and ultimately become very low at scale.
That's basically it. Most geothermal plants today are in locations where there are hot rocks, maybe geysers, close to the surface. "Deep geothermal" gets talked about, because temperatures high enough for steam are available almost everywhere if you can drill 3,000 meters down. There are very few wells in the world that deep, not counting horizontal drilling runs.
The economics are iffy. You drill one of the most expensive wells ever drilled, and you get a medium-pressure steam line. Average output is tens of megawatts.[1]
[1] https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2020/A...
Denser urban living is pretty energy efficient, and forcing lengthy commutes on people because of NIMBYism is a huge waste.
The 1 megajoule of useful electricity is also ultimately dissipated as low grade heat, but it can do work first (like generating light, or pumping water uphill).
Which (not sure if you did this intentionally or accidentally) brings up an interesting point on the parent comment and the LLNL sankey:
> It's always worth remembering that electricity only accounts for ~20% of global energy consumption (in the US it's closer to 33%).
That "global energy consumption" figure includes a lot of Rejected Energy going out tailpipes and smoke stacks turning burnables into electricity. A secret bonus of wind and solar is if you produce electricity without burning things, you actually decrease the energy demand! If you're not losing 70% of your energy consumption to the Rejected category, you suddenly need a lot less total energy.
When I drive my daughter to school when it’s -40 fucking degrees, a lot of the energy I use goes into heating my vehicle, swearing, moving and swearing. But this energy also leaks through my windshield, through my exhaust system and through my engine. This energy (heat) doesn’t provide any benefit to anyone and just leaks out into the atmosphere (which we’ve already established is trying to kill me).
That’s rejected energy. Or when it’s below -40, rejected motherfucking energy. :)
Similarly, better to have people be able to have reasonably energy-efficient houses than demanding they all live in apartments.
The only ones demanding anything are those who show up to try and stop apartments.
I went to high school with two guys who are working on geothermal as a means to remediate orphan wells. I’m biased in their favour, but the numbers make a lot of sense.
So even in a residential context, electricity is only about 1/4 of the demand. Across the whole country it's less than 300TWh out of 1500TWh, under 20%.
That excludes "imported energy" though, as in goods which used energy to make but were then imported.
(Source needed. This probably depends on a lot of variables in play.)
Plenty of people in dense urban areas are happy with living in an apartment and, where I live, buying a condo in the city is at least as frequent as buying a house 20 km away from it for the same price.
Living in suburbia has its downsides - long commute, very limited entertainment and cultural possibilities, very limited choice in schools. Not everyone loves cutting the lawn etc. either, I surely don't. If any of your family members has any disease that could flare up, ambulance response time tends to grow worse with the growing distance.
Of course, a lot depends on factors such as "is the transport authority willing to make public transport actually safe and nice". That requires keeping raving drugged lunatics out of it, plus paying enough money for it. AFAIK in the US, Republicans have an ideological problem with the "paying money for it" part and the Democrats have an ideological problem with the "suppressing antisocial behavior in it" part.
Chernobyl took out Welsh farming for years, and in a few places decades, because it spread a thin layer of bioaccumulative poison over the whole of Europe.
Know what else spreads a thin layer of poison over the whole of the world? Coal power.
The reactor breaks because it's a large device operated at high stresses (power/area, neutron loading). There are many components and joints that can fail.
BTW, this means fusion will be expensive, because getting all those components to be reliable right off the bat becomes expensive. No tiny cracks in the welds means expensive quality control.
Sounds like a very unique experience :)
I managed to get to a gas station with some stop leak in stock... If they didn't, I was ready to crack an egg in it.
Democracy just as lazy and apathetic is whatever the USSR counts as; the point of capitalism (which is different to democracy) redirect the laziness into something more productive — this works to an extent, but depends on competition which is greatly reduced in the case of nuclear reactors.
That it's a different axis than democracy-communism is also why the not-at-all-democratic military reactors around the world seem to be doing fine.
Driving can push up the low points (charge cars overnight), but heating would put a lot of demand in winter months, meaning a day time cold day in January with no wind will require a lot of dispatchable electricity, at night time in September with a gale blowing wind will be providing almost all the demand.
Nuclear doesn't really help as it's more expensive than the wind when it's windy and demand is low, and its impossible to build enough to cover the peak January demand unless you spread the fixed cost over the entire year, which means getting rid of every other form of electric production, and you'd still end up paying more per kWh than you would with other forms of storage.
Nuclear can't survive in a free market. It can't scale up to provide for areas of high demand, low supply, and it can't scale down to be affordable when there's high supply and low demand.
This is a fundamental difference from energy sources.
Energy storage is an important complement to energy sources, especially renewables, and can substitute for energy sources to a limited extent, but confusing them is a fatal error.
I'm sure that battery effect is a factor but it must be a relatively minor one.
After a few years of pumping heat out of the ground below the frost line during the winter, they'll freeze the ground solid and stop working (and possibly destroy the foundation of the house in the process, since often the pipes are installed in trenches around the house).
The only exception is if they're one of these few borderline systems that drill so deep they really are bringing up fresh energy from the depths, like some of the systems mentioned in the article.
See for example https://igshpa.org/igshpa-blog/cold-climate-ground-source-he...:
> Unlike air-source heat pumps that struggle to extract heat from frigid air, ground source heat pumps tap into a remarkably stable heat source: the earth itself. Below the frost line, ground temperatures remain relatively constant year-round, typically between 50-60°F (10-15°C). This consistency makes ground source heat pumps highly efficient even during the coldest months.
If you were building a ground-source heat pump to heat your house in the summer, you could get away with burying the pipes at a much shallower depth and in effect converting the earth into a low-temperature passive solar collector. But generally people want to heat their houses in the winter instead.
