... and should've closed with "Would you like a more concise or more elaborate version of this article?". 8-)

Well I shared the thread including your thought with Grok, and it said this:
-----
Here’s my actual, unbiased take on the technical debate (no Elon worship, no green hype, just physics and engineering reality as of 2025).
The original Slashdot skeptic is repeating a criticism that was 100% correct for the classic 1970s–2000s “hot dry rock” (HDR) projects (Los Alamos, Rosemanowes, Soultz 2000s era, etc.). Those really were conduction-limited. You drilled two wells a few hundred meters apart into 200–250 C granite, fracked a small volume, and watched the reservoir cool in months because heat was only replenishing by slow conduction through intact rock ( 2–3 W/mK). The recoverable fraction was tiny, and the impedance kept rising. That’s why HDR basically died commercially for 20 years.
Superhot / supercritical geothermal (400–450 C target, aiming for >500 C) is genuinely trying to escape that trap, and the physics does allow it—if everything works. Here’s why the critique no longer fully applies:

Energy density jumps by ~10× once you cross the critical point (374 C, 221 bar).
A kilogram of supercritical water at 500 C and 300 bar carries roughly 2,800–3,000 kJ/kg of usable enthalpy, versus ~300 kJ/kg for 250 C liquid water steam conversion in conventional geothermal. That alone reduces the mass flow (and therefore the parasitic pumping power and cooling load on the rock) by an order of magnitude for the same electrical output.
Heat transfer switches from conduction-dominated to convection-dominated.
In a well-designed, high-permeability fracture network, the supercritical fluid is buoyant and mobile. You get natural or strongly enhanced convection cells that sweep heat from a much larger volume of rock than the old HDR experiments ever touched. Surface area is now measured in square kilometers instead of hundreds of square meters.
Heat recharge rate in volcanic settings is completely different.
At Newberry, the background heat flux near the magma body is 300–1,000 mW/m (vs. ~80 mW/m continental average). Over a 1 km reservoir volume that’s hundreds of megawatts of continuous heat inflow. If your fracture cloud is big enough and permeable enough, you can pull 50–200 MW thermal more or less indefinitely without dropping the average rock temperature very much. (Fervo’s Project Red in Nevada—conventional temp, but still EGS—has already demonstrated ~3.5 MW from one well pair with negligible cooling over 18 months, and they’re only at ~190 C.)

Real remaining risks that the skeptic would be right to highlight:

Can you actually create and maintain a large, high-permeability fracture network at 500+ C and 10–20 km depth (or even 4–6 km near volcanoes) without it short-circuiting or sealing up with mineral precipitation? We don’t have field proof yet at those conditions.
Materials: drill bits, casings, pumps, and well cements that survive 500–600 C for 20–30 years do not fully exist off the shelf today. They’re being developed (high-nickel alloys, graphene-infused cements, etc.), but it’s expensive and unproven at scale.
Induced seismicity near an active volcano is non-trivial. Newberry is a shield volcano with low seismicity risk compared to, say, a subduction-zone stratovolcano, but still.
Economics: even if the resource works, LCOE has to beat new combined-cycle gas (~$40/MWh) and new nuclear (~$70–90/MWh) in the 2030s. The IEA’s “8 % of global electricity by 2050” scenario assumes superhot gets down to ~$30–50/MWh. That’s plausible only if wells become cheaper (thanks oil&gas tech transfer) and capacity factors stay >90 %.

Bottom line
The old “rock has terrible thermal conductivity, therefore geothermal is dead” argument is no longer a universal show-stopper for superhot volcanic/near-magmatic systems with modern EGS techniques. The physics really does flip in your favor above ~400–450 C. But turning that into thousands of gigawatts is still an engineering and materials challenge, not a solved problem. Mazama, Fervo, Eavor, Quaise, Sage Geosystems, etc., all have to demonstrate multi-decade performance at scale. The next 5–10 years of pilots will tell us whether the skeptics were merely early, or fundamentally right.
So: the ChatGPT answer you got was essentially correct on the physics and the generational shift. The Slashdot commenter is stuck in 1995 thinking, which is understandable—most of the industry was too until about 2018.
-----

If you think that this is incorrect information, a hallucination, or unduly sycophantic, I would like to hear your genuine case.

Disclaimer: European here.

There are well over a thousand food additives that are banned and illegal in Europe, some of which are classified as effing prime-grade toxic waste(!) - meaning they cannot even be legally disposed of in a drain or a regular landfill - that are "legal" food additives in the US.

It is proven beyond any doubt that forever chemicals accumulate in liver and other vital mammalian (read: also human) organs and cause chronic diseases beyond low threshholds and now they're supposed to be legal food additives?

This is insane. No wonder your cancer rates are through the roof.

I suggest you people raise a stink and write some letters to congress. And ramp up subsidies for organic farming and natural produce. And limit them for processed foods. US health is deteriorating at a measurable pace and you guys should want to change that.

Just sayin'.

Two thumbs up and good luck!

... on board this could eventually be the next big thing, like Blender for 3D stuff. I might even actually buy a Smartwatch some day.

Fortunately, we have you -- a knowledgeable human, who can propose the right points!

So, I asked Chat about what you said, and asked Chat-GPT to formulate a response that directly addresses your key points.
Let me know if it reads like randomly extruded text, or if it has relevance to your understanding and argument:

---
The Campi Flegrei project you’re describing was a natural hydrothermal system, not an engineered superhot-rock (SHR) system, and that distinction matters for both the chemistry and the physics.

A hydrothermal reservoir taps naturally circulating volcanic brine. Its fluid chemistry is whatever the rock has been stewing in for centuries: arsenic, boron, mercury, dissolved metals, HS, etc. The industry learned long ago that natural brines often destroy turbines, foul condensers, and require scrubbing that wipes out the thermodynamic efficiency. Those problems are real, and your experience confirms them.

Superhot-rock geothermal is a different class of project. It does not rely on natural brines, natural permeability, or natural aquifers. SHR / modern EGS systems:

Bring their own working fluid (usually treated water in a closed or semi-closed loop),

Create engineered fracture networks rather than using natural ones,

Operate in a supercritical regime (>374C, high pressure) where heat transport is dominated by convective sweep rather than slow conduction, and

Are sited where mantle heat flux is extremely high (e.g., Newberry), not just where water has accumulated in shallow formations.

The key point is that the problems you encountered at Campi Flegrei — toxic brine chemistry, turbine contamination, and power losses from scrubbing — are specific to hydrothermal geology, not to engineered SHR systems. SHR avoids most of that simply because it doesn’t use the volcanic soup; it uses injected water circulating through a designed heat-exchange zone.

Your numbers actually underline the potential: you were getting ~50 MW per well from a shallow (~350–400C) hydrothermal system with awful chemistry. Modern SHR aims for rock in the 400–500C+ range, with supercritical water carrying far more enthalpy per kilogram and without the brine-chemistry penalty.

Whether SHR proves economical at scale is still an open engineering question. But the Campi Flegrei outcome doesn’t generalize to SHR any more than the problems of early natural-steam geothermal plants generalized to modern binary-cycle systems.

Does this distinction make sense from your point of view?

Yes. It really is a moral duty to tell the Wright brothers that their pie in the sky visions have a track history of failure -- to remind them that there are good reasons flight isn't already a commonplace thing.

I talked with Chat-GPT to understand its argument, and the gist was: the critique about low thermal conductivity was absolutely correct for the geothermal attempts between ~1970 and 2010. But modern “superhot rock” geothermal is operating in a very different regime.

First, they can now induce vastly more fractures in the rock. Heat transfer in geothermal isn’t about the raw conductivity of solid rock - it’s about surface area. More fractures = more exposed hot rock = more efficient heat sweep. The fracture networks used today are orders of magnitude larger than the old HDR trials.

Second, the water isn’t just hot water or steam anymore. At these temperatures and pressures it becomes a supercritical fluid. That matters because it convects heat through the fracture network instead of relying on slow conduction. So you don’t get the old “hot spot next to the well / cold depleted zone” behavior - the fluid actively evens out temperature gradients.

Third, the sites they’re using now (like Newberry Volcano) have massively higher heat flux from below. Many of the early HDR projects were drilled into generic crustal hot rock with weak replenishment. Near a volcano, the heat flow is orders of magnitude higher.

Add to that the modern toolkit - horizontal drilling (mid-2000s onward), high-temperature drilling materials, computer-modeled fracture design, etc. None of this existed during the early HDR experiments that gave geothermal a bad reputation.

Chat-GPT summed it with a metaphor: the old Hot Dry Rock systems were like trying to heat your house using a candle in the corner. Tiny fracture zones, minimal surface area, conduction-limited, fast local cooling and slow reheating.

The new approach is more like engineering a large underground heat exchanger connected to a huge volcanic heat source.

And yes, you can overdraw heat - just like you can over-pump groundwater. But operators don’t have to push it that hard, and modern models tell them exactly how much heat they can sustainably take each year.

I don't understand these topics deeply? I'm hoping that you do, and that this will mean something to you.

I'm not an engineer, but here's what Chat-GPT thinks, when I shared your comment with it:

---

Not quite. This criticism is valid for old-school “hot dry rock” geothermal (1970-2010), but it doesn’t apply to the new superhot-rock designs.

It’s true that rock has low thermal conductivity and that conduction-limited systems cool locally if you withdraw heat faster than it flows back. That’s exactly why the early HDR [Lion: -- this means "Hot Dry Rock"] experiments never scaled.

But superhot-rock geothermal isn’t using the old model.

Three things have changed:

Supercritical water (>374C, high pressure).
At these temperatures you’re no longer circulating liquid water or steam. Supercritical fluid behaves like a gas in viscosity but carries heat like a liquid, and has dramatically higher enthalpy. It transfers heat through fractured rock convectively, not purely by conduction. That’s a completely different thermodynamic regime than the classic HDR studies.

Engineered fracture networks (modern EGS).
Today’s EGS looks much more like a controlled, high-permeability heat exchanger than a single injection well in a monolithic rock mass. You’re creating a huge surface area and letting supercritical fluid sweep heat through it. The limiting factor becomes the fracture network, not the bulk conductivity of a single block of granite.

Volcanic settings with very high heat flux.
The Newberry system is only a few miles from an active magma body. The heat inflow from depth is orders of magnitude higher than at the old HDR field sites. You still have to manage production rates, but you’re no longer relying on conduction through kilometers of cold crust.

The “if it were workable we’d already be using it” argument also doesn’t hold. We didn’t have:

* horizontal drilling at scale until the mid-2000s,

* the ability to design fracture networks with modern HPC,

* high-temperature drilling materials,

* or any commercial attempts at supercritical geothermal

until the last decade.

The physics hasn’t changed, but the engineering finally can reach the temperatures where supercritical convection dominates and where the geothermal resource is effectively thousands of times denser.

Superhot geothermal still has plenty of open questions (scaling, economics, long-term well integrity), but the “thermal conductivity of rock makes it impossible” critique is describing the previous generation of geothermal, not the current one.

... I of course mean other citations than that quasi-fraudulent British lawsuit that started this nonsense myth back in the early 90ies or so.

... with a metric ton of salt, but on the demographics of China and their impact he seems spot on. And let's be honest, there's not that much you can get wrong here. It's quite simple math.

... within this decade. And he's been doing that for a while. And his reasoning sounds plausible.

The blender crew effing rocks, that's for sure. I sure hope Ton Roosendahl is enjoying his (part-time?) retirement!

I'm listed as a donator because I'm actually one of those rare few who bought a commercial license back when Blender still was closed source and was being sold as a commercial product by NaN. They went commercial for a year or so after blender was available as freeware. I paid 250 Euros and still have the color-printed receipt. I might frame it and hang it on the wall some day. :-)

The infrastructure required to perpetually get decent to good quality petrol to where it's needed is insane. For electric you just need a battery, some solar cells and you're good to go. Petrol throughout south America is notoriously bad, often mixed with (bad) (m)ethanol and often a gable to fill in your tank. Its not uncommon for adventure bike riders to bring an extra spare piston and cylinder along in case you frag yours beyond repair and need to replace it somewhere in the ass-end of Patagonia.

That doorstep countries around the world are moving to solar and electric vehicles faster than developed countries makes perfect sense.

This is a detail many PC fanbois tend to overlook. And it's the reason consoles are so successful.

Point in case: I ditched hardcore PC gaming 25 years ago because it was becoming ridiculous with the constant hardware upgrades, fiddling with drivers and the mess that is M$ W1ndows. And I at one time had the most performant gaming PC available that costed roughly 5000$. I'm a computer expert but when even AMD went from one socket type to something like 5 different (Intel was already at roughly 10 different socket types back then) I got tired of keeping track, said f*ck it and left PC gaming alltogether. I just stopped the hardware upgrades, installed Linux for programming and the occasional Linux-native Unreal Tournament and Tribes 2 session and left it at that. This was in the late 90ies. I don't have the kind of space, time and attention anymore that PC gaming needs.

Roughly 15 years later I had some cash left and was curious about the new games such as the Deus Ex reboot and some discounted FarCry title and got an XBox 360, the last iteration just at the end of that generation that could run on a regular monitor without hassle. With all kinks fixed and a large cheap library of budget-priced games as GOTY premium editions and an affordable box that I knew would run those games with zero config fuss I was all set.

I've been with XBox ever since, always lagging 1-2 generations for price and stability reasons. I'm still using a Xbox One X as my main gaming rigg and it's totally fine. Yeah, I do miss mouse and keyboard occasionally, but I also enjoy being prolific with the controller by now and just leaning back on the sofa doing Open World Looter-Shooters, (A)RPGs or the occasional Spaceflight game. Every once in a while I ponder getting back into PC gaming but when I l then look at the prices, the science involded and remember the hassle of dealing with shitty operating systems, drivers, flaky software, etc. I quickly drop that notion again.

I might look into that new Steam Box thing, but I still have 82 games for XBox One alone, not counting my 360 titles. Most of these games I haven't played yet, so I'm not too much in a hurry. I also love the fact that the XBox is backwards compatible, which is a huge plus, Kudos to M$ for doing this. M$ W1ndows sucks, but with XBox they're still the global underdog and behave accordingly. And have me, a prime-time Linux user for 25+ years, as a paying customer, believe it or not.