WarOnPrivacy 8 hours ago

I worked on geothermal control systems a decade or so back. There are some less obvious applications for geothermal that reduce electric use (as opposed to generating electricity).

The systems I worked on were for cooling larger structures like commercial greenhouses, gov installations and mansions. 64° degree water would be pumped up from 400' down, run thru a series of chillers (for a/c) and then returned underground - about 20° or 25° warmer.

I always thought this method could be used to provide a/c for neighborhoods, operated as a neighborhood utility. I've not seen it done tho. I've seen neighborhood owned water supplies and sewer systems; it tells me the ownership part seems feasible.

  • wood_spirit 7 hours ago

    In the nordics it is common to have ground source heat pumps (brine in closed circuit pipe or bore hole) that are run backwards in summer to cool the house while actually assisting in storing heat back in the ground to extract in the winter. It’s a bit like regenerative breaking on electric cars.

    • jjtheblunt 5 hours ago

      There was a new in 1988 house in Champaign, Illinois, USA that used the same system, and i mention that because it was a normal modern house, and it's the only one i've heard of with that system.

      It seems so smart.

      • maxerickson 3 hours ago

        It's expensive. A relative has one in the northern Great Lakes, they wouldn't have installed it if their house had access to natural gas.

        • zrail 2 hours ago

          Our house came with one and we upgraded the unit a few years ago. It's very efficient in terms of units of energy consumed, but in my area of the world gas is significantly cheaper than electricity so it ends up being expensive to run.

          That said, we will install solar at some point and then it'll be "free" HVAC.

      • zdragnar 2 hours ago

        There's a pretty significant upfront cost in getting them drilled, and many homes need the vertical drilling if they don't have sufficient yard space for a horizontal system. It gets harder if you have your own septic drain field too, as that will complete for yard space.

        The cost difference is pretty massive- 3-10x for a vertical system. If you live in a city or a suburb with tiny lots, that's your only option though.

        Nat gas and central AC are way cheaper.

        • IncreasePosts 1 hour ago

          Air source heat pumps are insanely more efficient and just plain better these days too. It used to be that if the air was below 40F you couldn't heat your house with a heat pump. Now, you can heat your house even when it's -10F

          • SR2Z 1 hour ago

            If you can tolerate the price, I am _confident_ that you will pretty much always have better results using the Earth as your thermal exhaust, because you don't have to dig very far to find a large region that's pretty much always at 50 F.

  • readthenotes1 7 hours ago

    Isn't that similar to how neighborhood heat pumps work?

    https://www.araner.com/blog/district-heating-in-sweden-effic...

    • hunterpayne 4 hours ago

      Heat pumps require a specific temperate differential to work. So they work in zones with are a bit hotter or colder than you would like and so require moderate amounts of heating or cooling. They don't work in temperate zones nor in very hot or cold places. So Santa Fe or Minneapolis for example they work but Mexico City or San Francisco they don't. If you are in a place where they work and that isn't too dense or has earthquakes, go for it. If not, don't. There are businesses that will help you understand when they do and don't make sense. Those businesses don't sell heat pumps though (the businesses that sell things will almost always tell you it works, even when it doesn't, for example PV in the UK doesn't work).

      • sokoloff 2 hours ago

        I’ve never heard a claim that heat pumps won’t work well in a climate like San Francisco and, from looking at the annual temperature patterns, it seems like both air source and ground source heat pumps should work extremely well as they do in the “shoulder seasons” here in New England.

      • hyperbovine 2 hours ago

        Wait Minneapolis is definitely very cold for about half the year.

  • Animats 7 hours ago

    Shallow geothermal works fine for heating. And you can use the ground as a heat sink. But if you want to generate power, you need to get down to where temperatures can boil water. That's deeper than most oil wells. Fervo Energy claims to have found 270C at 3350 meters well depth. That's progress.

    • lostlogin 7 hours ago

      > if you want to generate power, you need to get down to where temperatures can boil water. That's deeper than most oil wells.

      That’s going to be very dependant on location.

      Here in NZ there are regions where water is boiling at surface level.

      According to the below, 18% of our power is produced with it.

      https://www.eeca.govt.nz/insights/energy-in-new-zealand/rene...

      • Animats 1 hour ago

        "New Zealand has an abundant supply of geothermal energy because we are located on the boundary between two tectonic plates. ... Total geothermal electricity capacity in New Zealand stands at over 900 MW, making us the fifth largest generator of geothermal in the world. It has been estimated that there is sufficient geothermal resource for another 1,000 MW of electricity generation."

        That's not all that much. That total would be about equal to the 75th largest nuclear plant in the world.

        Good sites where high temperatures are near the surface are rare. California has a few, but no promising locations for more.

        • lostlogin 33 minutes ago

          > That's not all that much.

          We don’t have many people. It gets worse’s though, we burn coal and are looking to fund a gas terminal. We have abundant other ways of generating power and subsidise an aluminium smelter for some reason.

          Coming up next, data centres.

          ‘Clean, Green New Zealand.’

      • thinkcontext 44 minutes ago

        You brought the conversation in a circle, since the point of this new technology is the geology you speak of is rare.

    • quijoteuniv 5 hours ago

      I think this looks interesting, but still very early stage. The “150 GW revolution” sounds more like theoretical potential, not something we will see soon in real deployment.

      Main problems: drilling is still expensive, managing induced seismic activity is not trivial, permitting can take long time, and you also need transmission infrastructure. Also not yet proven that companies like Fervo can scale this in reliable and low-cost way.

    • jeffbee 2 hours ago

      Nope. To efficiently tap geothermal energy, you need to boil something but not necessarily water. Isopentane, for example, boils at 28º at standard pressure, so they pressurize the secondary loop to raise the boiling point close to whatever the primary loop temperature is.

      The idea that geothermal only works well at steam temperatures is outdated 20th-century thinking.

      • emmelaich 2 hours ago

        But the energy in boiling isopentane would be less right?

        • jeffbee 1 hour ago

          Yes, the efficiency is worse, but as is also the case for solar power you need to get used to not caring much about efficiency. It is nuclear energy where the primary side is provided free of charge. The Carnot efficiency is almost without relevance.

          • micro2588 1 hour ago

            In geothermal there is still a lot of interest in efficiency and exploring different working fluids because binary systems now have efficiencies of 10-20%. That is why you see companies like Sage Geosystems working on developing / deploying supercritical CO2 turbines to try and boost practical power densities.

  • solarpunk 7 hours ago

    I think you're describing what is known as "district energy" systems.

  • quickthrowman 6 hours ago

    District heating and chilled water is uneconomical for single-family homes. It does work well in medium to high density areas.

    • gambiting 5 hours ago

      I don't know how economical that is, but just as an anecdote - the town I'm from in Poland has district heating to all single family homes, town of about 20k people. And coincidentally, I now live in the UK and a new estate near me has district heating to all the houses they are building, not apartment blocks. So it must make some sense to someone, or they wouldn't be outfitting 100+ houses this way.

      • hunterpayne 4 hours ago

        "I don't know how economical that is"

        Sure you do. Think about it. Its just drilling a hole and making electricity from the heat. We have been able to do this for a very long time. So if people aren't really doing it much, its not economical. If it was now becoming economical, the article would describe some new way of doing it that makes it economical. The article doesn't, so you "know" it isn't.

        PS This has been tried many time, it only works in very specific situations, usually places where building a full PP doesn't make sense or where you are making a lot of electricity for some other purpose (mining usually).

        • LeFantome 2 hours ago

          The “new” way is plasma drilling.

          • thinkcontext 40 minutes ago

            That's still a science project, they are piloting zapping a small hole to 100m. Very uncertain whether it will amount to anything.

        • thinkcontext 38 minutes ago

          > Its just drilling a hole and making electricity from the heat

          District heating does not involve making electricity.

Animats 7 hours ago

Oh, Fervo Energy again. They're trying to IPO, hence the hype. Wikipedia's warning: This article reads like a press release or a news article and may be largely based on routine coverage. (February 2026) This article may have been created or edited in return for undisclosed payments, a violation of Wikipedia's terms of use. It may require cleanup to comply with Wikipedia's content policies, particularly neutral point of view.

Here's a more realistic evaluation of Fervo.[1]

[1] https://www.latitudemedia.com/news/what-fervos-approach-says...

  • w1 6 hours ago

    This isn’t really an evaluation of the company, just explaining how they had to use different financing approaches as they grew and derisked their technology (which makes sense).

    Compared to some other new approaches for getting clean base load power, it seems like they’ve been pretty grounded and methodical.

    • Animats 4 hours ago

      They're way ahead of the microwave drilling people.

      There's no reason why this shouldn't work. But they've been at it for 9 years, with considerable funding, and it doesn't really work yet. That's a concern.

      • hunterpayne 4 hours ago

        "There's no reason why this shouldn't work."

        Geothermal has had the same problem for its entire history. That problem is that the water being heated goes through the ground (not in a pipe) to "gather" more energy. But this means that when the water comes back up, it has a lot of weird salts in it (and other things). Those salts cause corrosion, lots and lots of corrosion, far more than even a maritime environment. So the plant needs to be shutdown a lot of the time for repairs. And that's what makes it uneconomical. Also, the salts often contain things that require special handling which also increases costs.

        PS This is why geothermal works in Iceland where there is so much geothermal heat they can use pipes. In CA, they can't so it doesn't work there.

        • micro2588 1 hour ago

          Fervo uses engineered reservoirs in granitic basement rock so this is less of an issue. Hot rock in a working fluid can still dissolve silicates out of the granite and lead to scaling / degradation of the flow rates through the reservoir and that is a risk but chemical anti scaling treatments are used to reduce this.

          CA has the worlds largest geothermal power complex in the Geysers. That one field produces an equivalent amount of power as all the geothermal in Iceland and there are others.

      • mgfist 1 hour ago

        > There's no reason why this shouldn't work. But they've been at it for 9 years, with considerable funding, and it doesn't really work yet. That's a concern.

        It does work. They've had a pilot project producing 3 megawatts since 2023. But scaling takes a lot of time and money, particularly when it's something new and you have to go through a lot of operational learning.

        Shale took something like 30 years to become a thing. 9 years is nothing in the energy space.

        • micro2588 39 minutes ago

          It does work technically I think it is still an open question if it can work economically. There are issues of commercially viable flow rates / thermal decline rates that are harder physical limits you run up against and the pilot design doesn't address. In human timescale terms it's more like heat mining rather than renewable heat due to thermal depletion rate vs replenishment rate. These systems have a targeted lifetime of ~20-30 years and net power will decline over this timespan.

  • tptacek 2 hours ago

    That's Wikipedia warning about the quality of the Wikipedia page, not about the company.

pedalpete 4 hours ago

According to google, this would be almost 30% of total US energy production (135gw-150gw) and nearly 5% of total US energy consumption.

But what is the "breakthrough" if there is one? The article doesn't really suggest any breakthrough that is unlocking this potential energy? Or maybe I'm looking for a technological breakthrough where there isn't one.

  • hn_throwaway_99 4 hours ago

    4th paragraph of TFA:

    > Several companies are now building upon existing techniques for accessing geothermal resources by integrating enhanced geothermal systems (EGS) into operations. While conventional geothermal systems produce energy using hot water or steam, pumped from naturally occurring hydrothermal reservoirs trapped in rock formations underground, EGS use innovative drilling technologies, such as those used in fracking operations, to drill horizontally and create hydrothermal reservoirs where they don’t currently exist.

    • nusl 4 hours ago

      So it basically says nothing useful other than try to generate hype and make them look good.

      • thinkcontext 23 minutes ago

        No. Current geothermal projects need very specific geology to work, its very rare which is why geothermal is such a small blip in the overall energy picture. Enhanced Geothermal Systems (EGS), the technique Fervo is using, can create the conditions to be able to generate electricity. The hope is this will greatly expand the number of projects that can be developed.

        Doesn't that sound useful to you?

    • nandomrumber 3 hours ago

      Sounds like marketing hype to me.

      Geothermal reservoirs exist at depth.

      Drilling horizontally doesn’t magically reduce the depth, nor the problem that drilling in to hot rock is like drilling in to plasticine, at least for temperatures worth working with.

      • micro2588 1 hour ago

        In traditional fault hosted (not magmatic) geothermal the convection of the water up the fault brings the thermal energy closer to the surface where drilling depths are economical. This convection heats the surrounding rock and over hundred thousand - million of years brings the background temperature around a large volume at depth surrounding these systems considerably above traditional background geothermal gradients. By drilling into a much larger volume of impermeable hot rock surrounding a very small permeable fault hosted section you can considerably enhance the power potential of a traditional fault hosted geothermal system (the E in EGS). That is what Fervo is doing and why their projects are situated right next to traditional geothermal power plants.

        The assumption is that if you can increase drilling efficiencies enough than you don't even need a fault hosted system to bring that energy close to the surface, you can just drill down deep enough to get at similar gradients. That is a big assumption in the economics.

  • hunterpayne 4 hours ago

    There isn't one. They are trying to politically pressure a utility to build some geothermal plant. But utilities have engineers who will tell their bosses that this plan doesn't work. So the companies selling the geothermal plant are trying to politically pressure the utility to do yet another thing that they know won't work. PG&E for example has several geothermal plants which have been economic disasters and were and are being shutdown.

    • mgfist 1 hour ago

      > PG&E for example has several geothermal plants which have been economic disasters and were and are being shutdown.

      Those are very different from EGS

    • micro2588 1 hour ago

      The core breakthroughs were working with partners to develop PDC bits that enable high rates of penetration in drilling out these horizontal wells in high temp granitic rock and then demonstrating plug / perf fracture networks that have a high engineered permeability in these source rocks to support economical flow rates and heat transfer. These were considerable advances over previous efforts.

      There will be other learning by doing advances in how you structure your power plant design to take advantage of these to make practical long term power production possible (well spacing and injection / production placement / flow rate and temperature decline management).

  • skybrian 3 hours ago

    My understanding is that it's due to better drilling techniques. The industry learned a fair bit from fracking and they're learning more from experience as they apply it to geothermal.

    No particular breakthrough, but there's a learning curve and they learn more as they do more. Other industries sometimes work that way, too.

    https://www.austinvernon.site/blog/geothermalupdate2026.html

jmward01 6 hours ago

Here is an article that is a bit old but discusses the start of things [1]. It would be a bit ironic if fracking tech helped get us further from using natural gas. I think the reality will be if this gets established we will see rapid improvement as scale comes on line so if it is remotely economical now it will be massively better in 5-10 years. Of course the 'if' applies.

[1] (2023) https://time.com/6302342/fervo-fracking-technology-geotherma...

typon 48 minutes ago

What is the point of building energy outside of solar farms? I'm sincerely asking

  • applied_heat 16 minutes ago

    Night time? But batteries! Several cloudy days in a row? More batteries! Cost? -> a mix of sources becomes attractive

runicelf 3 hours ago

Would be great to see this in our lifetime

idontwantthis 4 hours ago

Is 150GW enough for a “revolution”? That’s about 10% of current total power production.

  • smallerize 3 hours ago

    Solar is at 7%. It's very significant.

davidw 5 hours ago

There's one of those sites near where I live. The numbers would be amazing if true, but feel a lot like "to good to be true" to me

https://www.opb.org/article/2025/10/06/super-hot-rocks-geoth...

  • micro2588 3 minutes ago

    Newberry Volcano is too good to be true in that there are few to none (outside of Yellowstone) equivalent sources of geothermal awesomeness at similar depths in the USA. Good for research bad for generalization of drilling costs to hit similar temperatures.

mskogly 7 hours ago

The whole continent of America made a breakthrough?