[pedalpete]

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.

[hunterpayne]

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.

[micro2588]

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).

[mgfist]

> 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

[floatrock]

They're adapting fracking techniques to use for geothermal, which opens up many more sites. Historically geothermal has had limited potential, and the best sites have already been developed. So geothermal + fracking creates a lot more viable land.

Traditional geothermal is you dig a really deep well and get a geyser of hot water or steam to come up.

Fervo is doing "Enhanced" or "Engineered" geothermal where you dig two wells: an injection and an extraction well. You frack the rock in between, creating lots of small channels for water to flow between them. The water absorbs the heat from the rocks as its circulating from the injection well to the extraction well.

The kind of rock that's good at this heat transfer is different from shale rock that oil & gas frackers have experience with... it's harder, less porous, not partial-dino-juice. So they're taking a lot of the same core concepts from the oil & gas industry (horizontal drilling, geology simulations, etc), but their IP is in adopting the techniques to work with geothermal-favorable rock.

Another interesting concept I heard Fervo researching: this kind of geothermal is not "baseload" style power, so there's a few tricks they can do to get better cost efficiency and peaker-like or battery-like behavior. Remember the two wells that form the circulation loop: injection and extraction? Well, you need pumps on both sides (remember, this isn't "geyser-style" geothermal where natural pressure and geology do all the work). Pumps take energy to run, something like 20-30% of the overall extraction output (you put a unit of energy in to run the pumps and you get 3-5 units of energy back out the other end). Not great, not terrible either... it's an energy return comparable to solar and wind. But what you can do is run the injection pump when power prices are low (ie when there's an excess of solar on the grid), pressurize all your fracked channels underground (the reservoir), and then when grid prices rise in the evening you run just the extraction pump to pull out the pre-heated, pre-pressurized water. You're still at a 3-5x energy return, but the time-shifting has made the cost multiplier more favorable.

My understanding is it's still in research phase, but Fervo is piloting this technique. Like another thread said, they're pre-IPO now, so they've been flooding the renewables media with all these stories. They filed an S-1 recently, but always read the eventual S-3 before considering your investment options blahblahblah.

[hn_throwaway_99]

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.

[nandomrumber]

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]

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 then you don't even need a fault hosted or similar system to bring that energy close to the surface, you can just drill down deep enough to get at similar temperatures. That is a big assumption in the economics.

[sunshinesnacks]

EGS has been around for at least 15 years. See AltaRock Energy as an example (I’m sure there are others). They started almost 20 years ago. https://en.wikipedia.org/wiki/AltaRock_Energy

[nusl]

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

[thinkcontext]

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?

[skybrian]

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

[dyauspitr]

It’s a stupid ploy by oil drillers to try and expand their existing capex to something more future proof. Their theory is to randomly frack the ground and hope superheated water shows up there. It’s probably just going to end up ruining existing groundwater sources.