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Deep geothermal energy is poised for a big breakout
- mensetmanusman 6y agoThis is covering deep geothermal, trying to get into the huge heat source from radioactive decay in the earth’s core. This is not covering back-yard geothermal for home cooling/heating. I had no idea such a small amount of the earth’s heat could be harvested to satisfy all of humanity’s energy need (assuming humanity doesn’t start doing stupid things when we have access to unlimited energy...)
- dang 6y agoOk, we've deepened the title above.
- rfrey 6y agoIn industry we usually refer to "geothermal" as heat from radioactive decay, and "geoexchange" from the backyard stuff, where the source is solar heating. You're not wrong, that just seems to be the way we get around constant disambiguation. I was the CTO for a Canadian geothermal company.
- cwal37 6y agoWe also just called it ground source when I briefly worked in the field. Although, in my experience, even though someone shells out $$$ for a "ground source heat pump" in their yard, it won't stop them from telling everyone they have geothermal.
- Nashooo 6y agoHere we just call them (water) heat pumps.
- AtlasBarfed 6y agoWell, assuming we can drill very deep, I would think the supervolcano calderas have massive amounts of energy that we could exploit and ... possibly ... avoid future extinction-level-event eruptions. I also wonder how deep would be sufficient to "dump" nuclear waste. I would think once you get to a sufficiently viscous level, heavy-element nuclear waste would slowly descend into the core. What could go wrong?
- Valgrim 6y agoIf I read the article correctly, Geothermal energy extraction involve pumping cold water in and hot water out. If I wanted to put nuclear waste somewhere underground, it would probably be very far away from the place I pump water from.
- eppp 6y agoWould probably be ok to just use for heat transfer.
- AnimalMuppet 6y agoWhy do volcanoes erupt? Because pressure builds up that is stronger than a weak/thin spot in the crust can take. If we drill a hole then the strength of the crust at the hole is... zero. Doing that in the neighborhood of a supervolcano might not be wise...
- allannienhuis 6y agoI expect the amount of heat one could extract would be absolutely negligible compared the the amount of heat in a supervolcano caldera, so I doubt there would be any affect at all.
- jws 6y agoPeople have pondered cooling Yellowstone's magma chamber by surrounding it with geothermal wells.† The result would be 5GW (for comparison that is 1/6th of California's needs) of clean energy at about $0.10/kWH for thousands of years and a significantly reduced chance of a supervolcano eruption event killing millions of people. It might alter or stop the geysers though, so it isn't going to go anywhere. [†] https://www.bbc.com/future/article/20170817-nasas-ambitious-plan-to-save-earth-from-a-supervolcano https://www.bbc.com/future/article/20170817-nasas-ambitious-...
- ginko 6y agoIf you would use the heat from earth's core to run power plants, presumably by leading in water and running a steam turbine, wouldn't that eventually heat up the atmosphere since you pump out the heat in the core faster than it would naturally?
- dmitriy_ko 6y agoNo. There's always heat coming to earth and radiating back to space. Amount of greenhouse gases in the atmosphere determine equilibrium temperature. Adding heat doesn't change equilibrium temperature.
- trophycase 6y agoNo offense but I have a hard time believing this. Isn't pumping heat from the center of the earth to the atmosphere more or less the same as having a larger amount of incoming solar energy? And certainly it would be hard to argue that more energy from the sun wouldn't heat the planet. Wouldn't the equilibrium temperature be both a function of energy in and radiation rate (which is also a function of temperature?)
- CorrectHorseBat 6y agoNo > Wouldn't the equilibrium temperature be both a function of energy in and radiation rate (which is also a function of temperature?) Exactly, and since we're not changing the energy in (that energy is going to reach us whether we pump it up or not), and thus the equilibrium does not change. Where else can all that generated energy go other than up?
- rwcarlsen 6y agoBut it would otherwise go "up" at a slower rate - so heat adding more slowly but over longer. Pumping heat up is effectively compressing this time horizon - resulting in a difference in rate of heat added. Now if that geothermal energy was replacing nuclear or fossil fuel use, then it might be a wash. But as soon as that energy replaces hydro, wind, or solar (which don't add new heat to the atmosphere - just use heat already there) - then we would increase the rate of heat energy being added to the atmosphere.
- mrfusion 6y agoWith the advances the boring company is making I wonder if we could just point one straight down (or at an angle) and cheaply make geothermal.
- yxhuvud 6y agoI suggest you read the article.
- rfrey 6y agoGeothermal has a problem in that the capital to build a plant is much higher (2-3x) that of a combined cycle natural gas power plant. Even though the fuel is free, in order to make the economics work you have to project power prices out 50 years. Usually when we scope power plants the proformas only go out 15 years. And by "make the economics work" I'm not talking about excessive returns. I'm talking about a <10% rate of return, getting the investment back in 10-14 years.
- edogg 6y agoWith the downturn in oil and gas in Alberta Is there a lot of talent and drilling rigs available? Maybe it is a cheap time to drill some holes?
- rfrey 6y agoIt seems like a natural pivot for Alberta, and we spent a lot of sweat trying to convince the government that it was good for drillers. Good for pipefitters and welders and millwrights too. No dice though, if anything I'd say the government actively sabotaged our company (retracted a $7m grant from the previous administration, for example). Just too green for them. There is a lot of talent available, and one of the drilling companies (Beaver Drilling) has made themselves the spokesman for the geothermal industry. That's what got things moving with at least the government paying lip service to the industry. I left just as Beaver was stepping in, though. As for costs: so many of the drilling costs are fixed - material costs for casing, consumables like drill bits and drilling slurry. Labor might be down but it's still several million dollars per hole.
- DoingIsLearning 6y agoWould this have similar seismic risk as fracking? Applying high pressure water injections into bedrock?
- allannienhuis 6y agoOnly some of the geothermal tech requires injection of fluids along the lines of Fracking. The article suggests for those cases the risks are lower, due to the different pressures and fluids required. Other techniques (closed-loop systems) don't require it at all (but do require advanced drilling tech).
- barney54 6y agoIn some locations there have been concerns about geothermal and induced earthquakes. http://www.seismo.ethz.ch/en/knowledge/things-to-know/geothermal-energy-earthquakes/geothermal-energy-and-induced-earthquakes/ http://www.seismo.ethz.ch/en/knowledge/things-to-know/geothe...
- dakna 6y agoDepending on where you drill, you might end up in a situation where some layers come into contact with high-pressure water and start swelling, resulting in raised surface levels. Most prominent example I know of, is the city of Staufen in Germany: https://en.wikipedia.org/wiki/Staufen_im_Breisgau#Geothermal_drilling_controversy https://en.wikipedia.org/wiki/Staufen_im_Breisgau#Geothermal... https://www.thelocal.de/20170818/this-historic-german-town-is-falling-apart-in-slow-motion-catastrophe https://www.thelocal.de/20170818/this-historic-german-town-i... To my limited understanding, this could have been prevented by a better geological survey.
- w1 6y agoalso fwiw, the induced seismicity from fracking was found to come from injected wastewater associated with post-frac oil production [1]. it's my understanding that the majority of these geothermal systems are injecting about as much as their pumping up, so stress doesn't build/you don't have that issue. [1] https://www.usgs.gov/natural-hazards/earthquake-hazards/science/myths-and-misconceptions-about-induced-earthquakes?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/natural-hazards/earthquake-hazards/scie...
- rfrey 6y agoFor anybody who is interested in this stuff, I was the CTO of a Canadian geothermal company, and I became convinced that it was folly to dig 4km down to get hot water when we are surrounded by waste heat in large industrial plants that is largely untapped. By way of example, I was working on a geothermal plant in Alberta that would generate 5MW and cost $60 million (CDN) to build. Similar heat can be found everywhere at surface, especially in Alberta which has a heavy industrial base. Harnessing the heat from industrial sources is exactly the same as a geothermal plant: only the source of heat is different. For example, I scoped a project on a natural gas pipeline compressor station. It used a RB211 gas turbine to drive the compressor. Capturing the waste heat from the exhaust stack of that engine gave us 7MW of net generation, at a cost of $30 million, and much lower operating expenses to boot. 58% of the energy we generate each year is lost, much of it (upwards of 20%) as industrial waste heat. That's terajoules of electrical generation potential globally, just from the easily captured stuff. It's not exactly like geothermal energy, because you have counterparty risk in that the cement factory (or whatever) might close. But the tech is identical to geothermal, and there's no exploration risk or digging expense.
- JoeAltmaier 6y agoSounds like low-hanging fruit. But not really scalable. A 7MW plant sounds OK for some applications. But a really big geothermal plant might compete with nuclear.
- rfrey 6y agoIt's a good point, but there are many grid experts who argue that smaller, distributed generation is more robust and reliable than larger, 500MW+ plants. Outside a few areas, most geothermal plants are quite small: I doubt we'll ever see one over 15MW in Canada, for example. A 7MW plant doesn't sound like much, but if you're cookie-cuttering 9 of them along a line, costs come way down since they're all essentially identical. I did some back-of-the-envelope calculations and if we did all the larger (over 15000hp) natural gas compressor stations in the US and Canada, we'd be looking at something like 42TWh per year of generation. That compares to 68 TWh for all deployed utility solar (2018 tho). That's just gas compressor stations, which are about 15% of the industrial heat generated in the US.
- X6S1x6Okd1st 6y agoI'm surprised that we're already generating almost half as much energy as all the decay energy in the core. It did not take long for the human race to start being a major force on the planet after we started agriculture.
- pfdietz 6y agoIt's not clear there's much decay energy in the core. That would depend on whether uranium, thorium, or potassium would dissolve in high pressure liquid iron-nickel. Uranium and thorium are highly concentrated in the Earth's crust, btw, relative to the rest of the Earth.
- rwcarlsen 6y agoIf by "core" - you mean to exclude the mantle, then yes, we don't know exactly how much radiogenic [1] heat generation there is. But if we are using the term "core" loosely here to refer to everything under the crust, then a very significant fraction of the heat is generated via radioactive decay. [1] https://en.wikipedia.org/wiki/Earth's_internal_heat_budget#Global_internal_heat_flow https://en.wikipedia.org/wiki/Earth's_internal_heat_budget#G...
- pfdietz 6y agoBy "core" I mean the part called the "core".
- X6S1x6Okd1st 6y agoMy b, I meant below the crust
- ggm 6y agoI want to believe in GeoThermal. A recent experiment in Australia went bad, this really saddened me because the underlying model clearly works (Iceland, NZ) but something about the combination of drill, frack, extract and process to energy just didn't work out, nor did the post experiment remediation (IIRC) I also believe, that we actually deplete both deep heat, and deep coolth. Deep heat, you have to keep expanding the deep heat extraction zone or create pumped states in a wider area somehow, Coolth: London underground was lovely and airconditioner cool, it now has 100+ years of soaked in heat and is significantly hotter than it used to be.
- rfrey 6y agoThe brine in the permeable rock is heated by radiation from the earth's core. It is pumped to surface, power generated, then injected back into the earth at a sufficient distance, so that by the time it flows back to the extraction well it will have been re-heated to the original temperature. So no, the subsurface will not cool over time (except with some crackpot "technologies" like one mentioned towards the end of the article that rhymes with "never"). It's actually harnessing the radiation of the earth's geology. There are some places where power is extracted faster than the geology can support. In those cases electrical generation tapers off. This is happening in Turkey for example. But it's because of greed, not because of anything inherent in the technology.
- ggm 6y agoThanks. I thought it was that some prior radiative heat was being consumed, and wasn't being refreshed by deep water brine. Maybe thats what you said: the rate of extraction can exceed the rate of renewal?
- rfrey 6y agoYes, extraction can easily exceed renewal rates. Good resource management is key to longevity.
- ggm 6y agoI was (I think) referring to the cooper basin project. It was non-viable on LCOE given transmission costs and rate of extraction. I can't find the remediation story links, maybe confused this with other energy/fracking problems, but the do note the fracks made mag 3.7 earthquakes, which may have been played up as a risk-side problem.
- kaiwenwang 6y agoThere was a company called Quaise in this field I read about in The Engine's portfolio, though I don't know enough about this subject matter to make much of a comment.
- wwarner 6y agoI feel like in the long run this has to work. This is drawing energy from gravity itself.
- ChrisFoster 6y agoActually the heat arises from the natural decay of radioactive elements within the Earth. In the far future it will be gone! It's true that in the early history of the Earth there would have been heating from gravitational contraction of the protoplanetary disc. But as soon as the Earth swept its orbit of material this source of heating disappeared. There's an interesting footnote in the history of physics where gravitational contraction was the proposed mechanism for solar luminosity: https://en.wikipedia.org/wiki/History_of_Solar_System_formation_and_evolution_hypotheses#Kelvin-Helmholtz_contraction https://en.wikipedia.org/wiki/History_of_Solar_System_format...
- p1mrx 6y agoHow do the economics of scale look for geothermal? Say we're building terawatts of these things, what's the incremental $/watt?
- hamolton 6y agoI was curious about the economics of building geothermal plants as a California statewide infrastructure strategy, since I assume it's a pretty good place for geothermal, so I did some quick maths from info I found online. Apparently CA consumes about 7% of the electricity in the US, at 259.9 TWh, therefore averaging a consumption of only 29.65 gigawatts; the capacity is actually 75.9 GW [1]. An energy.gov site [2] says a typical large geothermal plant only costs $2.5 to build per watt of capacity! Compared to a lot of huge-ticket federal and even statewide budget items such as the $686 billion military budget, eliminating off-peak non-industrial natural gas energy production with socialized electricity seems doable. [1] https://www.eia.gov/electricity/state/california/ https://www.eia.gov/electricity/state/california/ [2] https://www.energy.gov/eere/geothermal/geothermal-faqs#:~:text=The%20initial%20cost%20for%20the,%240.01%20to%20%240.03%20per%20kWh https://www.energy.gov/eere/geothermal/geothermal-faqs#:~:te....
- pabs3 6y agoWhat are the failure modes and maintenance requirements of these sorts of systems?
- jungletime 6y agoSomething to consider is that even at those depths there are bacteria and living things in the soil. Depriving them of heat, might disrupt another ecosystem that is providing food for things above or below. https://www.bbc.com/news/science-environment-23855436 https://www.bbc.com/news/science-environment-23855436
- anttisalmela 6y agohttps://www.st1.com/geothermal-heat https://www.st1.com/geothermal-heat Finnish Energy company ST1 is about to finish construction of 40MW geothermal plant near Helsinki, Finland. They've drilled to depth of 6.5km.
- cmarschner 6y agoCan somebody explain to me the limits of geothermal exploitation? It seems to be a limited resource to me. Even more limited than fossil fuels. Those will replenish in a few million years. But heat from the earth’s core will be gone till the end of time. No? Let alone effects on earthquakes or changing the magnetic field and these kind of things.
- garyclarke27 6y agoThere is probably a natural nuclear reactor in the Earth’s core. Think when the earth was formed, heaviest elements like Uranium would naturally concentrate at the core. Therefore Geothermal is potentially an unlimited resource, at least until the reactor runs out of fuel, but I would guess thats millions if not billions of years away.
- dwd 6y agoPortland, Victoria had geothermal nearly 40 years ago. https://www.abc.net.au/local/audio/2013/12/13/3910988.htm https://www.abc.net.au/local/audio/2013/12/13/3910988.htm
- Havoc 6y agoDoes this contribute towards global warming? In the literally sense - taking heat out of the core and into the surface level environment presumably increases temps?