I wish the best for the geothermal industry, but the phrase “could outperform” is doing a lot of heavy lifting. Geothermal thermal has essentially zero growth, in the US, in the last 20 years. And there is basically no growth planned in the near future, or at least nothing on the EIA’s or FERC’s upcoming generation list.
I’m skeptical that geothermal will ever make a significant impact in the US. Though it might make a difference in much farther north places, where solar struggles.
"Our gyrotron-powered drilling platform vaporizes boreholes through rock and provides access to deep geothermal heat without complex downhole equipment.
Based on breakthrough fusion research and well-established drilling practices, we are developing a radical new approach to ultra-deep drilling."
This company looks promising in the geothermal space. They are looking to be able to create 10km boreholes in 100 days. This would make geothermal viable anywhere in the world. Bonus points if you create the borehole next to an existing coal plant to use the existing turbine and infrastructure.
Bhauth wrote an analysis of this idea, and tldr is that trying to get an energy payback on literally vaporizing such a long cylinder of rock is brutally difficult, probably enough to make the economics of the plan unworkable.
This is a really interesting perspective but I wish they finished writing the equations out. My attempt at verification didn't match.
Per [1], “[wells] with a regular production casing diameter of 200-250 mm have an average capacity of 5.5 MWe”. Quaise has deep bores that could potentially have higher temperatures, but let's stick with 5 MWe.
At the article's 12 MWh/m³ for drilling, and 250mm bores of depth 10km, WolframAlpha tells me that is 6 GWh.
Divide through, you get 1000 hours or about a month. This doesn't match their “significantly over 10 years” they gave before mentioning waveguide losses.
The main difference I suppose is the thermal conductivity comment, where I didn't follow why Quaise wouldn't be able to use enhanced geothermal approaches. More specifically I think that if a Quaise well has ~1% the energy output of a normal geothermal well, it's pretty weird to frame the problem as about the energy cost of drilling, and not the whole factor-100 reduction in energy output.
To be clear, this seemed like an interesting article and I'm not claiming my napkin math is definitive, I really am neither an expert nor someone who has spent a lot of time investigating this. I do think some more clarity on how the math looks would help their case.
The article you linked is about conventional geothermal wells, which drill into reservoirs of hot water; they just have hotter water than has been typical. Extracting hot water is not limited by thermal conductivity of rock, but what Quaise plans to do is.
Enhanced geothermal involves fracking. Typical proposals involve creating crack paths between 2 nearby wells by fracking from both. It's been tested some but so far has not been economical.
Apart from the cost issues of enhanced geothermal so far, Quaise plans to drill deeper to higher temperatures to reduce power block costs. Sufficiently hot rock flows a little bit which makes fracking ineffective. Fracking also doesn't work as well with supercritical water. (If not drilling to rock hot enough to flow a little bit under high pressures, it would be much better to use conventional drilling techniques.)
I'm afraid I'm not really following the argument though. I don't have the technical background to judge how economical EGS is or not, I just want to understand this energy-based argument. I checked to be sure, and Quaise's initial plans (per cofounder Matt Houde) are indeed EGS-based[1], just deeper. It seems correct to me that if they succeeded at building wells that way, they would produce at least comparable energy to standard wells.
It's entirely possible that EGS just doesn't work at really deep depths as you state here, but this seems like a qualitatively different argument to the one presented in the article.
[1] https://youtu.be/yz6rRw59Huw?t=675 "but what we're interested in in Quaise is this novel idea here all the way on the right which we call like to call superhot rock EGS systems"
Actually, they address the energy balance question at the end of that talk.
https://youtu.be/yz6rRw59Huw?t=3016 "[...] we could be using around five megawatts for the drilling process to drill our wells, and let's say we use that five megawatts over a year to drill three holes, so we get an injector and two producers. We predict that configuration of the two producers and an injector at superhot conditions can produce something around 50 to 100 megawatts of electrical energy, again owing to the benefits of producing this superhot, supercritical steam."
They also answer a question on borehole stability, admittedly claiming largely that they don't know.
> It's entirely possible that EGS just doesn't work at really deep depths as you state here, but this seems like a qualitatively different argument to the one presented in the article.
A different argument to the one presented in the article, you say. Huh.
I suppose I can't claim to know more about geothermal than the author of that blog post, but if you check again, you'll find it does mention EGS. Apparently something made the author decide the problems with Quaise using that are non-obvious enough to need explanation.
cf. "but I wish they finished writing the equations out"
The article mentions EGS but, as far as I could tell, only seemed to present it to contrast it with the claim that Quaise is using a worse single-bore strategy.
If I'm just misreading, and it sounds like you're saying I am?, it'd be really helpful to show your working so I can see where the models are differing. There is a factor 100 difference somewhere, it shouldn't be that hard to spot!
You say, “if there's enough pressure to make a little crack, then the fluid can instantly expand and immediately make a big crack”. My admittedly quite surface level view of the research is that it is viewed as feasible in this regime.
“Close to the brittle-ductile transition conditions of pressure and temperature, new findings suggest that fractures are sufficiently permeable to allow fluid circulation and, in case of insufficient fracture density, enhancement strategies are likely to be successful”
I also believe that EGS fracture enhancement marginally prefers hydro-shearing (crack expansion) rather than hydro-fracking (crack formation), so if creating cracks is problematic, that leaves options open.
I also note that to my understanding gas fracking is already a thing, cf. nitrogen fracking. So gaseous behavior doesn't obviously seem like an instant write-off to me.
I'm sure that isn't convincing to you, but it's a bit challenging for me as a layman wrt. geothermal to see why I should trust your gut here, so to speak, and I'm wondering if you have a concrete argument I can evaluate on merits?
For example,
"The hypothesis that the brittle–ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10−16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability–depth relations proposed for the continental crust show no drastic permeability reduction at the BDT."
I'm definitely not claiming to take these on faith, I'm just saying I haven't really been given a reason to believe those arguments are less trustworthy than your claims otherwise.
It makes it all sound like a problem of engineering, not of physics.
It's really hard to vapourize all that rock and suck it out to the surface with a vacuum. But it's really hard in the sense that the vaporised rock might recondense and stick to the sides of the hole, not in the sense that vaporising the rock costs more energy than you get out of the hole in its 30-year lifetime.
Would it be possible to blow chilled air down the hole that would quickly condense the rock vapor into particulates that don't stick and instead get vacuumed out ?
Look up Fervo Energy, I think you will be surprised how quickly their method will grow and expand as they gain more experience with their current projects.
The problem is dominantly that with traditional techniques the US doesn't have useful geothermal energy resources, so not having geothermal energy historically doesn't mean that newer approaches that aim to work in far more areas will also fail to scale.
Skepticism is reasonable around any new technology, but the arguments for geothermal are convincing enough that it seems easily worth the attempt.
Yeah, I'm not sure large scale geothermal electrical production will ever be a thing outside some specialized locations like Iceland.
I do think geothermal has a part to play, specifically for heating and cooling of neighbourhoods and multifamily developments. The construction has to move a ton of dirt anyway, so might as well install some ground loops while you're at it. If you're forced to drill due to site conditions, the load is lower than pure electricity generation meaning the wells are not that deep. For private homes it's far too expensive to be much more than a curiosity, but amortized across a whole new neighbourhood or collection of apartment buildings it's very affordable. Especially in northern climates accessing the consistent ground heat source/sink that allows you to run heat pumps at max efficiency all year is a huge win and is a huge amount of electricity you never need to generate in the first place.
> "I'm not sure large scale geothermal electrical production will ever be a thing outside some specialized locations like Iceland."
You may be underestimating the extent of geothermal power production that already exists around the world. For example, California's Geysers[1] and Salton Sea[2] geothermal complexes are some of the largest in the world, generating more electricity than all of Iceland's geothermal power plants combined.
I think you underestimate the scale of geothermal available. The US is the largest geothermal power producer in the world though no one thinks of the US as that. Not coincidentally, it also sits on top of the largest high-quality geothermal basin in the world, essentially the entire Mountain West.
The US barely taps these resources at all despite leading the world. Ironically, much of the pushback on developing these geothermal resources in the US comes from environmental activists.
While I agree with you generally, the price I was given was $50k for geothermal heat pump all in. Considering my house has risen in value by 200k over the past 3 years and I intend on it being a permanent family home, it's really not out of the question, especially considering the potential increase in extreme heat events and the impacts on energy.
I understand people see this as an underperforming investment but I instead see it as de-risking.
I’m skeptical that geothermal will ever make a significant impact in the US. Though it might make a difference in much farther north places, where solar struggles.
https://www.eia.gov/electricity/data/browser
https://www.eia.gov/totalenergy/data/browser/?tbl=T01.02#/?f...