Getting deep to hot rocks is important, but reducing the thermal resistance around the borehole is also important.<p>Some schemes fracture the rock between two boreholes, but this requires fiddly positioning of the wells as well as the fractures. Another interesting approach is to increase the thermal conductivity of the rock around a single well. Much of the thermal resistance is in the rock close to the well (as can be seen by examining the relevant integral), so this doesn't have to affect too far out to have a significant effect.<p>A company XGS Energy recently raised $20 M in series "A" funding for this. Their fluid (which is forced into fractures around the borehole) is proprietary, but is thought to contain graphite dust. Graphite can be three orders of magnitude more thermally conductive than rock, so incorporating it into even narrow fractures can have a major effect.<p><a href="https://news.ycombinator.com/item?id=40434975">https://news.ycombinator.com/item?id=40434975</a><p><a href="https://jpt.spe.org/hot-rock-slurry-developer-of-emerging-geothermal-tech-readies-for-field-tests" rel="nofollow">https://jpt.spe.org/hot-rock-slurry-developer-of-emerging-ge...</a><p>(the field tests mentioned there must have been successful, as they raised that $20 M subsequently.)<p>Because this technology involves a single well that remains sealed from the surrounding formation, it could be used in existing played-out oil or gas wells, some of which go quite deep (although that's in basins with low geothermal gradients or else the fossil fuels would have been destroyed.)
It's like if only we put more resources towards potential societal altering technologies like these instead of [insert random SAAS app]. Maybe tech investors aren't very comfortable with projects outside their domain knowledge and expect an quick return. Quaise last financing round was something like $20M...
Dumb question: is there any use for this for horizontal drilling? I'm imagining scaling up the size of the drill head to the size of a car-carrying bore hole, vaporizing the rock (or whatever gets in your way) and using some of it to recondense into tunnel liner, and blowing out the rest of the ash either back out the whole tunnel or via vertical(ish) vent tubes drilled periodically from the tunnel roof up.<p>Though maybe the tunnel liner part is too much of a stretch. It sounds like the vaporized rock wants to turn to ash. I don't know if there's a way of concentrating the once-solid parts and keeping it hot enough while routing it to the tunnel wall. It just seems like a cool set of problems to solve, resulting in a self-contained (minus the energy source) burrowing drill that can create arbitrarily long stone tunnels underneath (non-volcanic) land.<p>DIY lava tubes!
If this microwave drill is vaporizing rock, how do they keep the vapor from re-condensing on the drill, wave guide, and shaft walls and eventually closing up the spaces between them causing things to get stuck?>
I’ve thought for quite some time that deep well geothermal could be a sleeping giant in energy.<p>The Earth itself is a giant fission reactor and molten metal thermal battery, but for some reason nobody thinks about it.<p>This would be far easier than fusion or even next generation full cycle fission but it’s barely funded.
I have often thought that in the future, there'd be a machine that you could scoop raw earth into (like "Mr. Fusion" in the movie "Back To The Future II") -- any kind of raw earth -- and the machine would automatically separate the raw earth into its constituent elements...<p>Now, such a device would probably seem a little bit far fetched...<p>But the first step in making such a device, if it could ever be engineered, would be to melt the inserted raw earth into a hot liquid state. (From this hot liquid state further chemical refinement processes could be completed, such as scooping out heavier elements from the bottom and lighter elements from the top of the liquid. Any emitted gasses could be captured and cooled down, liquified, etc. From there further chemical refinement processes of the liquids could take place, ultimately resulting in refined Elements being output...)<p>This technology -- the ability to "melt rocks" (aka, the ability to melt raw earth, any raw earth notwithstanding its chemical composition) might just enable the taking of that first step to creating such a machine...<p>Such a machine, should it ever exist, would find great application on Mars in the future, should it ever be able to get there...<p>Anyway, I wish this company a lot of luck in their endeavors!
Has anyone calculated how much energy could be extracted before the cooling of the earth's crust, due such geothermal extraction, would turn irreversible the reservoir and unleash worse consequences than those "greenhouse gasses" mentioned?<p>From how such progressive temperature change (extraction) would affect the dynamics of the Earth's core, among other things, to how it would affect such temperature to the nature chemical processes on the surface, how it would affect vegetal life (cultives), and so on.<p>The planet is big, but we are talking about, lets say, a century of use or more. Has anyone calculated were would be the limit of holes (on geothermal a new hole each XX years due area cold down) before the "we never guessed that X could happen"?
This seems to have tremendous potential, and not just for geothermal!<p>However, one issue with geothermal that I didn't see addressed is that iirc, geothermal systems start out great, but as water/fluid is pumped down and back up hot, minerals rapidly deposit themselves on the plumbing and decrease the system efficiency and ultimately kill it. Could this system be used to more quickly, cheaply, and regularly perform maintenance, or is this just one good step to get broad geothermal applications, and that remains a problem to be solved?<p>It's be great to hear from any experts in the field - thx!
This is pretty interesting but it seems like there’s a massive component of this system that is yet to be proven viable—from the article:
“Drilling a hole is challenging enough,” says Tester. “But actually running the reservoir and getting the energy out of the ground safely may be something very, very far off in the future.”<p>Is there any existing +3km deep geothermal well energy system in use?
> which itself yields no greenhouse gasses<p>Does anyone know how much of the atmosphere's heat comes from geothermal energy as opposed to solar radiation? By extracting geothermal energy we'd be increasing that effect in the short term, but would it even be significant?
Inaccurate title. "Finds" implies it is being or has been used. More accurate would be "Fusion tech proposed to be used in geothermal energy drilling."
"The deepest man-made hole, which extends 12,262 meters below the surface of Siberia, took nearly 20 years to drill. As the shaft went deeper, progress declined to less than a meter per hour—a rate that finally decreased to zero as the work was abandoned in 1992. That attempt and similar projects have made it clear that conventional drills are no match for the high temperatures and pressures deep in the Earth’s crust."<p>This is true. Neither the article nor the CEO of the microwave drill company say why.<p>At that depth, rock isn't a solid. It behaves plastically. The traditional tri-cone bit used could make progress, but it kind of just started "massaging" the rock. The bit (as all bits do) wore out. They pulled the drill string out of the hole to put a new bit on. The borehole would close back in during the multiple days it took to pull 40kft of drill string out, change the bit, and put it back in. Progress was not possible.<p>Unless the microwave drill includes some enormous cooling system (that works 40kft down hole even when the drillstring is removed!), they will face the same issues.<p>Also, separately, I saw pictures of the resulting lab-drilled hole on LinkedIn the other day. The hole shows a high rugosity (qualitative description of the roughness of a borehole wall). Similar photo here - <a href="https://spectrum.ieee.org/media-library/image-of-a-rock-surface-with-a-melted-hole-in-the-middle-that-appears-to-extend-deep-into-the-rock-surface.jpg" rel="nofollow">https://spectrum.ieee.org/media-library/image-of-a-rock-surf...</a>. That's a ugly hole, and would be very difficult to run casing into it.<p>Further - traditional well drillers' #1 focus is controlling pressure downhole (typically done by varying the density of the drilling mud). If the pressure becomes too great, a blowout can happen, which is bad news for everyone involved (see the BP Deepwater Horizon incident). For geothermal wells, they presumably will try to avoid hydrocarbons. However, rock far above water boiling point can cause a BLEVE (boiling liquid expanding vapor explosion), which is also undesirable. Super curious to see how they intend to control bottomhole pressure with statements like this - "Instead of pumping fluid and turning a drill, we’ll be burning and vaporizing rock and extracting gas, which is much easier to pump than mud."