alt Hacker NewsI've always been curious why a cost-effective widespread implementation of geothermal energy has never been considered a holy grail of energy production, at least not in the public debate. Much of the discussion is so focussed on nuclear fusion, which seems so much harder and less likely to be reliable.
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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".
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.
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 have been numerous trials that had to be stopped because of the triggered earthquakes... Geothermal is not so easy.
Harder absolutely but "less likely to be reliable"?
If economically viable fusion was "cracked" what would the nature of it's unreliability even be?
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.
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.
Power flow is in general very low - ca 50-60 mW/sq.m
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.
> a holy grail of energy production
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...