Probably because not everywhere on earth has the same easy access that Iceland has. The article mentions this:

> 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.

I think it mainly depends on how easy it is to access that energy. I went to Tuscany last year and to my surprise there were geothermal plants everywhere. I have never heard about these plants beforehand, but here they are in Italy quietly powering the countryside and heating greenhouses to grow basil all year around.

Drilling is one of those things which used to be extremely expensive but has very gradually come down in price. Thanks, ironically, to the oil industry. It's unsexy because there's no "silver bullet" waiting in the wings.

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".

There have been numerous trials that had to be stopped because of the triggered earthquakes... Geothermal is not so easy.

Because unless you sit on top of a volcano, amount of renewable geothermal energy is minuscule. In most places on Earth it's somewhere around 40 mW/m2 (i.e. accounting for conversion losses you need to capture heat from ~500 m2 to renewably power one LED light bulb!). In other words, in most places geothermal plant acts more like a limited battery powered by hot rock, so unless drilling is extremely cheap, it does not make economic sense compared to other energy sources.

There is a crazy amount of energy available everywhere but it is not in the interest of the very powerful very wealthy existing players. This isn't some grand CONSPIRACY. For example oil companies may construct energy investment portfolios that would quite sensibly acquire promising energy related research. They do a simple cost benefit analysis then chose to modestly further research it or shelve it. They turn it into valuable pieces of paper that accumulate value over time. What is there for them not to like about it?

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.

Why not is explained in David McKay's book Sustainable Energy - without the hot air

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.

> falling back to coal thanks mostly to AI

citation needed

> The war to have solar plants over more coal is falling back to coal thanks mostly to AI.

Also, due to solar not panning out at scale.[1]

More seriously, coal is just cheaper and, with incentives being removed for green energy, it's the cheapest and fastest option to deploy. It's dead simple and well understood reliable power.

[1]https://apnews.com/article/california-solar-energy-ivanpah-b...

> We can't even declare total victory with LED bulbs over incandescent.

The LED bulbs I have access to (whatever's in the aisles at Home Depot, Costco, etc.) fail much more frequently than the incandescent bulbs I used to buy, and produce an uglier light that is less warm even on the softest/warmest color settings.

My suspicion is that incandescents were at the "end" of their product lifecycle (high quality available for cheap) and LEDs are nearing the middle (medium quality available for cheap), and that I should buy more expensive LED bulbs, but I still think that there are valid "complaints" against the state of widespread LED lighting. I hope these complaints become invalid within a decade, but for now I still miss the experience of buildings lit by incandescent light.

The other thing with AI--the LED revolution was led on this idea that we all need to work as hard as we can to save energy, but now apparently with AI that's no longer the case, and while I understand that this is just due to which political cabals have control of the regulatory machinery at any given time, it's still frustrating.

Not really how that works. Also earths core is being heated from nuclear decay and tidal effects. It’s getting 10’s or TW worth of heat until the sun expands and eats the earth. https://en.wikipedia.org/wiki/Earth's_internal_heat_budget

That's a different "geothermal" - the correct name is "ground source heat pump" or in your neighbor's case, a pond-source heat pump. Those exploit the temperature stability that occurs some small numbers or meters subsurface for heating in the winter and cooling in the summer.

"Geothermal energy" involves drilling down to hot rock to tap intense heat to run a turbine that produces electricity.

Geothermal is fission, and wind, solar, and batteries are fusion at a distance. In both cases, the failure scenarios are benign vs traditional fission generation. It's fine to keep striving for fusion humans control, but the problem (global electrification and transition to low carbon generation) is already solved with the tech we have today. It took the world 68 years to achieve the first 1TW of solar PV. The next 1TW took 2 years. Globally, ~760GW of solar PV is deployed per year (as of this comment), and will at some point hit ~1TW/year of deployment between now and 2030.

Geothermal is a great fit for dispatchable power to replace coal and fossil gas today (where able); batteries are almost cheaper than the cost to ship them, but geothermal would also help solve for seasonal deltas in demand vs supply ("diurnal storage").

https://reneweconomy.com.au/it-took-68-years-for-the-world-t...

https://ember-energy.org/data/2030-global-renewable-target-t...

I also love geothermal for district heating in latitudes that call for it; flooded legacy mines appear to be a potential solution for that use case.

Flooded UK coalmines could provide low-carbon cheap heat 'for generations' - https://news.ycombinator.com/item?id=45860049 - November 2025

Ive been very pro nuclear my whole life, but a part of me is disheartened by the mega projects that commercial fission deployments have become (even if the reasons are bad) that’s a problem that nerfs traditional fission. If nuclear remains both political, extremely bureaucratic and requires public investment, it just won’t be the solution, and not because the tech or physics is bad, but the decision makers & investors can no longer organize large infrastructure projects effectively (except maybe China). This is not unique to nuclear.

Having smaller scale local power generation, whether it’s SMRs, solar, wind or geothermal, there’s a huge advantage in terms of economy, investment, and politics.

The Berlin one also had some promising news today: https://www.adlershof.de/en/news/successful-tests-on-undergr...

We have to see if and when any of them goes into production, but the technology seems very interesting