I'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.
It always has been. Our problem is switching over existing infrastructure without asinine complainers ruining the revolution. We can't even declare total victory with LED bulbs over incandescent. The war to have solar plants over more coal is falling back to coal thanks mostly to AI. Pushback on geothermal will arrive, I guarantee it.
at some point we will figure out that because we took some much energy out of earths core that it stops spinning and causes the magnetic field to collapse ;-)
People across the road from have geothermal, driven by a 1.5m-deep pond right near their house. Their heat never costs more than $100 a month in the winter.
It's nuclear fission. It's always been nuclear fission (well, at least since the '50s) and it will continue to be until we commercialize fusion reactors. Everything else is nice to have but it's like NIH syndrome.
Instead of drilling deep, there is also an intersting case for storing cheap solar energy as hat in piles of dirts in the summer to power turbines in the winter: https://austinvernon.site/blog/standardthermal.html
There are scifi stories that have that kind of premise. Here's one, about electric power: "Damned if you don't" by Randall Garrett (https://www.gutenberg.org/cache/epub/24064/pg24064-images.ht...). I think there was also one about teleportation, although I can't remember where I read it.
Baseload generation is useless in 2025. It's in the name; it's called "base load", not "base generation".
Base generation was a cost optimization. Planners noticed that load never dropped below a specific level, and that cheapest power was from a plant designed to run 100% of the time rather than one designed to turn on and off frequently. So they could reduce cost by building a mix of base and peaker generation plants.
In 2025, that's no longer the case. The cheapest power is solar & wind, which produces power intermittently. And the next cheapest power is dispatchable.
To take advantage of this cheap intermittent power, we need a way to provide power when the sun isn't shining and the wind isn't blowing. Which is provided by storage and/or peaker plants.
That's what we need. If added non-dispatchable power to that mix than we're displacing cheap solar/wind with more expensive mix, and still not eliminating the need for further storage/peaker plants.
If non-dispatchable power is significantly cheaper than storage and/or peaker power than it's useful in a modern grid. That's not the case in 2025. The next cheapest power is natural gas, and it's dispatchable. If you restrict to clean options, storage & geographical diversity is cheaper than other options. Batteries for short term storage and pumped hydro for long term storage.
Iceland's hot water was a culture shock to me in 2 ways:
1. The host at our apartment encouraged us to leave the windows cracked and the heat on for good air circulation.
2. The hot water (at the taps) has a sulfer smell, because it's (also) piped geothermal water. My host explained they also had a water heater upstairs in their home because they preferred "heated cold water" over "hot water", which is a funny distinction to those of us who do not have the latter.
Note though that the sulfur smell from hot water in Iceland is only a thing in certain areas in Reykjavik, and perhaps some locations around the island.
This is due to the hot water in those regions literally being pumped out of the ground and into homes, and on a completely separate plumbing system. Majority of other areas use heat exchangers with pristine cold water, thus no smell nor taste is transferred.
So if you are staying in any other municipality in the capitol, you can use the hot water in cooking directly without boiling cold water. It's the same.
I was wondering how feasible it would be to reuse abandoned oil pumps for geothermal energy. A closed loop system [1] would probably be the most appropriate, with energy generation by spinning of a turbine by steam that gets recycled. I don't have the expertise and was wondering if someone can share a bit of knowledge with the rest of us.
Purely as an aside, I had the pleasure of visiting Iceland in August and it was great. Truly beautiful, rugged land.
Another way they've utilised geothermal energy is with large, sophisticated greenhouses which allow growing of many produce they would otherwise import. I only had the opportunity for a brief visit but a lot of it looked hydroponic with really interesting monitoring and control technology. (Plus the biggest bees this Antipodean has ever seen! These suckers were so big they didn't buzz, they rang the doorbell.)
It probably also depends on where you are and how deep you need to drill. It seems to be working out for Munich in Germany, there are a couple of city districts (including mine) that are heated by geothermal, and they invested in this since the early 2000s. Can't really find an english page for the whole project though: https://www.swm.de/unternehmen/geothermie
I hadn't realized that the IDDP had hit magma! That's very exciting! Obviously I'm very out of date, since that was in 02008.
However, I'm skeptical that geothermal energy can be economically competitive with solar without major innovations in heat engines, no matter how abundant the energy is and how easily you can get that energy to the surface.
https://www.eia.gov/analysis/studies/powerplants/capitalcost... outlines the estimated costs (five years ago) of a 650MW peak ultra-supercritical coal power plant without carbon capture; the total capital cost estimate comes out to US$2.4 billion, which is US$3.70 per peak watt. Of that, I think the only line item that wouldn't be the same in a 650MW peak ultra-supercritical geothermal plant is "Mechanical – Boiler Plant", which is US$905 million, leaving US$1.5 billion, US$2.30 per peak watt. (I'm not even sure you could eliminate even all of that US$905 million in a geothermal plant; some of it might be plumbing you'd also need to pass heat from your downhole heat exchange fluid with the ultra-pure deionized water you use to drive the delicate steam turbine. But let's suppose you could.) Of that US$1.5 billion, US$155.2 million is "Mechanical – Turbine Plant", so the turbine alone costs 24¢/Wp.
But SEIA last year published https://www.seia.org/research-resources/solar-market-insight.... They have a set of cost breakdowns for “turnkey installed price” for power plants, coming in at 98¢ per watt for “utility-scale fixed-tilt”, slightly higher than the previous year and almost half due to about 40¢ for the PV module itself. Residential is at 325¢, with about 20¢ for the PV module. That's even in the US, where the EIA report's estimates were sited, despite the US's prohibitive import tariffs on solar panels from China, which makes most of the world's solar panels.
Mainstream PV modules are now 12.3¢ per peak watt https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... (except in the US), which would drop SEIA's cost estimates from 98¢/Wp to 70¢/Wp, even in the absence of any other cost optimizations in solar farm design.
Now, utility-scale fixed-tilt solar farms typically have a capacity factor of around 20%, depending on latitude, because the sun is below the horizon half the time and somewhat slanted and/or clouded most of the rest of the time, so 70¢/Wp is really about US$3.50 per watt, not counting the batteries. But geothermal typically only has a capacity factor of around 74% in the US https://en.wikipedia.org/wiki/Capacity_factor#Capacity_facto... so US$2.30/Wp is really US$3.10 per watt.
That leaves you 30¢/Wp (74% × ($3.50 - $3.10)) for geothermal exploration and drilling. And if you can reduce the 82% of the solar 70¢/Wp represented by the non-PV-module costs by a little bit, or if you're equatorial enough that your PV capacity factor is 23% or above, that's going to zero or negative. I think the average PV capacity factor in California is something like 29%, though that isn't fixed-tilt and therefore has slightly higher costs.
Also note that the PVXchange page I linked above lists "low-cost" solar panels as having fallen to €0.050/Wp this month, a new historic low, which is 5.9¢/Wp. That's a 50% price decline from two years ago.
One underappreciated challenge in geothermal is simply the distribution of usable rock formations — low-prevalence resources. Better drilling reduces the rarity penalty by making more sites viable. Similar structure to many screening problems: improve detection and you can shift what counts as "reachable."
To me the most important fact to keep in mind about geothermal is that the energy flow across the crust is ~0.1W/m^2. Compare that to the sun which has >100W/m^2 even at high latitudes. Of course this does not mean geothermal is useless (in particular heat pumps, if you count those, are great), but it goes a long way to explaining why geothermal isn't seeing the same explosion as solar.
Maybe this is a stupid question, but is there any downside to harvesting heat from the planet? Would we slow convections by cooling it and then cause some weird ass problem?
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[ 3.7 ms ] story [ 45.7 ms ] threadThe renewables are so cheap and quick to provision it's hard to see how fission can compete.
Seriously this would be such a dream!
Turns out that the best battery is literally 10 feet away* - and you don't even need to charge it!
*if you want to make steam its a few thousand, but for heating and cooling its literally just 10 feet!
Base generation was a cost optimization. Planners noticed that load never dropped below a specific level, and that cheapest power was from a plant designed to run 100% of the time rather than one designed to turn on and off frequently. So they could reduce cost by building a mix of base and peaker generation plants.
In 2025, that's no longer the case. The cheapest power is solar & wind, which produces power intermittently. And the next cheapest power is dispatchable.
To take advantage of this cheap intermittent power, we need a way to provide power when the sun isn't shining and the wind isn't blowing. Which is provided by storage and/or peaker plants.
That's what we need. If added non-dispatchable power to that mix than we're displacing cheap solar/wind with more expensive mix, and still not eliminating the need for further storage/peaker plants.
If non-dispatchable power is significantly cheaper than storage and/or peaker power than it's useful in a modern grid. That's not the case in 2025. The next cheapest power is natural gas, and it's dispatchable. If you restrict to clean options, storage & geographical diversity is cheaper than other options. Batteries for short term storage and pumped hydro for long term storage.
1. The host at our apartment encouraged us to leave the windows cracked and the heat on for good air circulation.
2. The hot water (at the taps) has a sulfer smell, because it's (also) piped geothermal water. My host explained they also had a water heater upstairs in their home because they preferred "heated cold water" over "hot water", which is a funny distinction to those of us who do not have the latter.
This is due to the hot water in those regions literally being pumped out of the ground and into homes, and on a completely separate plumbing system. Majority of other areas use heat exchangers with pristine cold water, thus no smell nor taste is transferred.
So if you are staying in any other municipality in the capitol, you can use the hot water in cooking directly without boiling cold water. It's the same.
[1]: https://en.wikipedia.org/wiki/Closed-loop_geothermal
Another way they've utilised geothermal energy is with large, sophisticated greenhouses which allow growing of many produce they would otherwise import. I only had the opportunity for a brief visit but a lot of it looked hydroponic with really interesting monitoring and control technology. (Plus the biggest bees this Antipodean has ever seen! These suckers were so big they didn't buzz, they rang the doorbell.)
However, I'm skeptical that geothermal energy can be economically competitive with solar without major innovations in heat engines, no matter how abundant the energy is and how easily you can get that energy to the surface.
https://www.eia.gov/analysis/studies/powerplants/capitalcost... outlines the estimated costs (five years ago) of a 650MW peak ultra-supercritical coal power plant without carbon capture; the total capital cost estimate comes out to US$2.4 billion, which is US$3.70 per peak watt. Of that, I think the only line item that wouldn't be the same in a 650MW peak ultra-supercritical geothermal plant is "Mechanical – Boiler Plant", which is US$905 million, leaving US$1.5 billion, US$2.30 per peak watt. (I'm not even sure you could eliminate even all of that US$905 million in a geothermal plant; some of it might be plumbing you'd also need to pass heat from your downhole heat exchange fluid with the ultra-pure deionized water you use to drive the delicate steam turbine. But let's suppose you could.) Of that US$1.5 billion, US$155.2 million is "Mechanical – Turbine Plant", so the turbine alone costs 24¢/Wp.
But SEIA last year published https://www.seia.org/research-resources/solar-market-insight.... They have a set of cost breakdowns for “turnkey installed price” for power plants, coming in at 98¢ per watt for “utility-scale fixed-tilt”, slightly higher than the previous year and almost half due to about 40¢ for the PV module itself. Residential is at 325¢, with about 20¢ for the PV module. That's even in the US, where the EIA report's estimates were sited, despite the US's prohibitive import tariffs on solar panels from China, which makes most of the world's solar panels.
Mainstream PV modules are now 12.3¢ per peak watt https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... (except in the US), which would drop SEIA's cost estimates from 98¢/Wp to 70¢/Wp, even in the absence of any other cost optimizations in solar farm design.
Now, utility-scale fixed-tilt solar farms typically have a capacity factor of around 20%, depending on latitude, because the sun is below the horizon half the time and somewhat slanted and/or clouded most of the rest of the time, so 70¢/Wp is really about US$3.50 per watt, not counting the batteries. But geothermal typically only has a capacity factor of around 74% in the US https://en.wikipedia.org/wiki/Capacity_factor#Capacity_facto... so US$2.30/Wp is really US$3.10 per watt.
That leaves you 30¢/Wp (74% × ($3.50 - $3.10)) for geothermal exploration and drilling. And if you can reduce the 82% of the solar 70¢/Wp represented by the non-PV-module costs by a little bit, or if you're equatorial enough that your PV capacity factor is 23% or above, that's going to zero or negative. I think the average PV capacity factor in California is something like 29%, though that isn't fixed-tilt and therefore has slightly higher costs.
Also note that the PVXchange page I linked above lists "low-cost" solar panels as having fallen to €0.050/Wp this month, a new historic low, which is 5.9¢/Wp. That's a 50% price decline from two years ago.
Fu...