Geothermal Energy: How Big is the Potential?

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There is a lot of energy right under our feet, a relic from Earth's hot past as a ball of plasma. But how much can geothermal energy realistically do for us? What technologies are currently being pursued, what are the risks, and is it even carbon neutral? In this video we have collected all the relevant facts and numbers for you.
The footage of Staufen at the beginning of the video comes from Tom Scott's video that you can watch in full here: • The German town that's...
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Many thanks to Jordi Busqué for helping with this video jordibusque.com/
00:00 Intro
00:53 How Much Geothermal Energy is There?
06:37 What are the Challenges?
13:08 What Can New Technology Do?
16:07 What Are the Risks?
19:51 Summary
20:21 Into The Impossible With Brian Keating
#science

[@SabineHossenfelder]

This video comes with a quiz that lets you check how much you remember: quizwithit.com/start_thequiz/1694173328172x234359580857268500

[@michael-vl1mn]

Sabine with the deepest respect a maser works differently from a laser. RE

[@pyrsartur3675]

Your intelligence and “dry” sense of humor is such a hilarious and productive mix. Your message is so much more effective because of your creative delivery.

[@jarichards99utube]

YES...!!! : ) -70SomethingGuy

[@davidelliott5843]

“Rapid heating and cooling otherwise known as a British summer.” So true.

[@sdogg2152]

I literally thought the same thing. These jokes are presented so directly and are dropped from no where. Very funny

[@timothyandrewnielsen]

"Geothermal is clean". LOL. Yea, it's so clean to let all that gas into the atmosphere! Totally natural! Oil bad! hahahahaha

[@whisped8145]

I miss science presentations like this. Everything's just poppy energetic voices and hip corporate background music with ugly animations and superficial coverage and explanations. When I was a tadpole, the science shows on TV weren't all super stiff, but retained dignity and a mature sense of curiosity over wonder that also appealed to children - otherwise I probably wouldn't have watched as much. Even as a teen, when this shift happened on TV as well, those new shows, and those that changed their style to the new, began to repulse me and just felt like wasting my time. At worst, when they're dangling a carrot of the one important bit of information, and then maybe drop it at the end of a needlessly prolonged talk, part or full on documentary - and even then often needlessly phrased as a question. When then politics came in to recolour everything, especially in history/archeology I... lost a lot of interest really quick; but that's its own topic. I'm glad this channel seems free of that malarky as far as I can tell from what little I have seen so far. Happy to have stumbled upon this channel.

[@stephenfoulard3484]

In Dr Hossenfelder's Wikipedia bio, it mentions her post-doctoral work at U-of-A, Tuscon. When she said, "and before you know it, you have people driving around in pickup trucks with bumper stickers complaining about the government," I blurted out, "she HAS been to Arizona!"

[@larrya7822]

About 15 years ago, I had my house installed with a geo system (a heat exchange , 15,000 dollars US). They dug about 10 feet in the ground to put the pipes. It actually worked quite well. My furnace didn't go on very much. Even the manufacturer was surprised. They said it would go on when the temperature drop below 40 degrees f. I found it to be better (more in the 30s f.), but the water table level is quite high in my area. I live in Michigan U.S.

[@andvil01]

It's another way of geo energy. That is heat from the groundwater. Sun energy.

[@uomoman8775]

How long do those wells last. It’s my understanding that they collapse and you have to re-drill it

[@larrya7822]

@uomoman The pipes were put in horizontal, not vertical. 4 of them at 20 foot lengths. They were very thick wall pipes. At that depth, even if a truck ran over the top of where they were buried, it would not damage them.

[@malectric]

Typical drilling depths in New Zealand are about 2.5km in the Taupo region. It helps greatly to have a supervolcano handy that you can drill into.

[@johnalden948]

See above The Yellowstone caldera is ready to blow. We could get a lot of geothermal AND save North America.

[@malectric]

@@johnalden948 Statistically speaking Taupo is overdue for a biggie as well but unlikely and unpredictable. I lived there for 10 years while growing up. During the mid-1960s we experienced a swarm of earthquakes day and night which were felt while sitting at a desk in school and frequently woke me up during the night. Like all rhyolitic calderas with a huge pool of magma beneath them; the ground is subject to frequent movements - "restless caldera". There have been several largish earthquakes centred near the last main active vent during the past year or two. There is big untapped geothermal system beneath the lake itself. There is a number of geothermal power plants in steam/hot water zones around the northern end of the lake.

[@anonymous-rb2sr]

doesn't drilling kilometer deep boreholes towards magmatic chamber of active volcanoes.... create problems? Like I know the state of our current instrumentation for looking into the ground, they're very bad, we can at best get some very very blurry giant blobs of density, so we have basically no idea what we're drilling into (I imagine there are temperature probes on the head of the drills to give more info than the seismic dataa 3D reconstructions, and you probably don't meet lava before drilling into some very warm rock first, then again, maybe you do) All this to say I hope they know what they're doing and they're only making boreholes VERY far away from any possible magmatic fissure or magmatic chamber locaticion Then again, what would even happen if you directly drilled into one? Would it create a full on eruption or would it just very slowly vent gas and liquid in a controlled manner that could even be stopped if the tunnel was collapsed?

[@malectric]

@@anonymous-rb2sr All I can say is that extracting superheated water from geothermal reservoirs in the Taupo volcanic zone has been successfully done since early 1950s with no problems such as you are suggesting. It is generally these types of volcanoes that have geothermal systems associated with them. They do know what they are doing. Various techniques are used to locate the reservoirs including conductivity, gravity, seismic sounding etc. and of course, drilling. I know of no volcanoes that have erupted lava because of drilling anywhere in the world. Likewise, exploratory drilling of core samples into fault zones doesn't cause earthquakes AFAIK. The scale of tectonic processes simply dwarfs anything we do. Having said all that it is true that extraction of fluids from drilled wells has been known to cause seismic activity e.g. oilfield depletion in the U.S. and probably some minor activity in the Wairakei geothermal field (the ground has sunk over time). But significant earthquakes in the region are generally centred near the last active volcanic vents under the lake, well away from the borefields. Data is available from GNS (Institute of Geological and Nuclear Sciences) in New Zealand which maintains a website detailing tectonic activity.

[@anonymous-rb2sr]

​@@malectric yeah so basically they've been doing the smart thing and not the greedy thing and staying well clear away from any sort of more molten zone the reason I was worried is because I know what sort of 3D visualisation tools and technology humanity currently has access to and they're all terrible, at best we can get city sized 3D blobs that could maybe be something, we can detect continental plates deeping down, detect low density high density zones, detect the level of reflectivity and also guess somewhat the material properties by the speed of signals, but at the end of the day, we just don't have ANY technology currently to be able to get some sort of fine 3D picture or scan of what is essentially a solid rock, the closest technology I know to that goal would be muon scanning, which works really well, but you need to be on both sides of an object and it can't be too big, it's basically a high tech way to give an X RAY to a hill or building All this combined means that we can't really detect things like "subsurface fissures", we can look at a blurry 3D image and go, "yeah there are probably a lot of fissures somewhere in that blob" but we can't visualise the individual ones, due to the whole "solid rock" thing, but again I don't see how there could be any danger so long as you stay way far away from any area with pockets of molten rocks Also on the topic of weird underground pipe related topics, if you're intrested in that, some other very weird and fun stuff I've learned about is about oil spills and fires, basically underground liquids, be they magma, water or oil are constantly under pressure and WILL get out to the surface if there is a path, and it requires very strong pumps to do things like geofracking where you pump back water, and this creates a problem when your oiljacks begin to uncontrollably spill out oil This is a problem both the USA and soviet union faced, and this is where the fun and intresting stuff begins, the USA had to estinguish oil wells that had been set on fire during their invasion of Iraq, the way they did it was by blowing out the flame with a lot of explosives, the soviets had a very different approach, they didn't want to stop the flames, no, they wanted to squeeze shut the underground pipes, how did they do that? Well they used nukes, I'm not kidding, the way the soviet union went about closing shut drillholes and oil pipes was to literally drill another hole next to it, and blow up a nuke to compress the earth and crush the pipe I'm obliviously thinking about this because this method would probably work to shut off a pipe that began to spew magma as well if you like the topic and had never heard of it here it is lol: kzbin.info/www/bejne/i3m7pKlur92aeZo

[@PhysicsLaure]

I was an exchange student in Basel near Stauffen at that time. 😵 The geothermal project in Basel lead to several earthquakes within a few months... It really scared us because the old buildings aren't designed to resist so many earthquakes!

[@SabineHossenfelder]

oh wow!

[@SLYdevil]

Retrofitting is costly because of the lack of knowledge, bureaucratically, for the need & the need for laws to cut away costs local governments add to renovations. There is no need to pay a tax that serves to slow a country's ability to make safety and security/ environmental improvement to buildings, etc.

[@PhysicsLaure]

@@SLYdevil Basel was destroyed 1000 years by an earthquake. Everyone was excited at the idea, and then scared because it might happen again. Since then, there is a lot more research on earthquake risks, and new projects trying to be less invasive 🤞

[@SLYdevil]

@@SabineHossenfelder When we gonna get the next 'I Saw the Future'? I don't care about what anyone says: Put the Maths in the Music & Visualization Explanations, & slap a club beat to it - just for fun. Either way, if the desk & telephone gag is your creative outpouring, I'm getting a bucket ready. You could tour with Lindsey Stirling & Dr Becky! I got really excited about the possibility of a Multiverse making that line-up inevitable. I just have to dial in the right settings. It absolutely feels like we find ourselves in the Negative20Questions page of this Multiverse, if we're damned to a Multiverse. Which, I fear somehow powered by the N20Qs & consciousness's picking at the scab of the thought of the completed rings of the Many Worlds reasoning, may have self-made it this way. But hey, I have alot of military-related head injuries & ya know what? That can cause religious thought & beliefs more accepted by the poor paratrooper with the bruised cantaloupe. So, ta-da!

[@kellikelli4413]

And just think of how many of those Geothermal Energy Plants there are on Earth. They can create quakes maybe even Volcanic eruptions 🤔 Iceland obviously does it right, how did they figure it out.

[@precursors]

As a drilling engineer who has been drilling geothermal wells since 2009, I approve this video.

[@cynicalpenguin]

Did you used to be mayor of Staufen by any chance?

[@seltonk5136]

Let's have a great boobs

[@coreyham3753]

Great presentation on the plus and minus sides of geothermal.

[@mikeytodorov134]

Has it made you feel like you’re helping save the planet?

[@precursors]

@@mikeytodorov134 Has your desk job made you feel like you're helping save the planet?

[@victorlewis3251]

I love the way that you explain things. You keep it simple, you use relatable examples and your deadpan one liners are hilarious!

[@alfredneuman6488]

Amazing, a German with a sense of humor!

[@Bialy_1]

@@alfredneuman6488 The whole point of the video is->Germans did not do it then it must be not posible or not economical... As a Polish i can asure you that we know about German flaws and lack of the humor is not the issue, oversized EGO is. They did not know how to decode their Enigma machine so they asumed that it is not posible... 3 Polish mathematicians on the other hand did broke the code and started decoding it in 1932. They did not know how to make antena that mounted on a metal ship will be able to detect direction of the incoming radio signal so they asumed that u-boats can use radio all the time and not be detected... but Polish engineer made that antena for British ships and British destroyers were changing direction of the escorted convoy when ever u-boat radio transmision was infront of them... Manhatan Project is another example of stuff that was to hard for mighty German scientists...

[@jonaswox]

at least to the best of my knowledge. You are one of the best impartial science communicators.

[@bonniepoole1095]

Wow! I've never seen such a thorough reporting on geothermal development. Thank you! Fascinating!

[@tmst2199]

Isn't it terrific? One of my Sabine favs for sure.

[@timothyandrewnielsen]

It's all bogus.

[@alanlight7740]

It seems a very thorough accounting of where the industry was 30 years ago. A shame she didn't mention Eavor or Greenfire.

[@dannync95]

I never realized it’s potentials until now.

[@chrisgoetsch1964]

I wonder if sound frequency could be implemented into an application like this.

[@Thomas-gk42]

Seems so easy, complicated in detail. Very interesting and informative. I was in Staufen last summer by bicycle, I can report, it still exists

[@MrMawnster]

Depends where you live, in oil producing areas of the world the drilling expertise exists

[@mumbairay]

Begs the question re Turkiye earthquake and all this geothermal

[@hanfred]

@@mumbairay Not really, there's a big fault line because of continental drift and earthquakes have been documented for more than 900 years in the region.

[@n4nln]

You didn’t mention any of the geothermal projects geothermal projects funded in the previous decade by the US Dept of Energy and US Venture Capital the tune of multiple hundreds of millions of dollars. It turns out drilling the holes is the likely to be the least of your problems. Circulating water through formations is an excellent way to create a superheated solution of many things that are wildly corrosive and/or abrasive. It can chew-up the plant machinery and plumbing at an astonishing rate. Worse, if the flow becomes depressurized or slows down, things precipitate. One project generated many cubic meters of material per day. Then there is the problem of forcing circulating fluid down the hole once pressures reach useful levels. The pumps required to do that are large and use a lot of power. They are also seldom available in superalloy that can withstand to circulating fluid’s destructive chemistry and abrasive power. These considerations add further constraints on what might be productive geothermal sites, and even with careful selection, the cost estimates of a plant to use the holes is much more than previously imagined. I am a geothermal fan - we have geothermal heat pumps in our house. But the comparison could not be less useful.

[@seltonk5136]

Chesticles are too perky

[@MoreImbaThanYou]

That Invasion joke totally caught me off-guard. Well played.

[@tonyfernandes3557]

Your well prepared, succinct, intelligent and informative videos keep my mind alert! The subtle and dry ironic touch is unmissable!

[@TukozAki]

Exactly this. Sabine is one that'll help going to non invasive video platforms such as Nebula :-)

[@bigbirdwpg]

You're, not your :-)

[@TheChaznw]

My brother worked at The Geysers, one of the largest geothermal sites in the world, for about 10 years. He said keeping the equipment running was a challenge. The sulfur content in the steam meant the equipment was constantly being eaten away. They also had large piles of sulphur to get rid of.

[@jimurrata6785]

Sulphuric acid is a very common feedstock in chemical industries. I'm surprised they don't have a ready market for the byproduct

[@Master_Yoda1990]

I'd take that sulfur. Don't ask questions 👀

[@iang3728]

Yeah it is a mess. But sulfur is a commodity you sell, not "get rid of". People toil in sulfur mines daily.

[@TheChaznw]

@@iang3728 My brother only took me to The Geysers once. I have no idea what they did with the huge pile of sulphur. Probably went to a chemical plant somewhere, as some of you suggested. If any of you would like some contact Sacrament Municipal Utility District (SMUD).

[@mk1st]

So much more than just “drilling a deeper hole” Thanks for the insights.

[@MrMawnster]

It's crazy the level of tech and expertise that goes into " just drilling a hole" eh? hahaha The oil people know though and it's a beautiful transition for them I think

[@aether3697]

Is that what she said?

[@theadventuresofbrockinthai4325]

Hello, I'm an American living in Thailand but I come from an area in southeast California. The Imperial Valley has at least 11 geothermal plants but back in the 90's when Los Angeles was having blackouts from not having enough power. They had, the day before, called all of the geothermal plants and told them to shutdown because they didn't need there power. At the time the geothermal plants in the Imperial Valley (4) could produce enough energy to power all of Southern California. The reason for them to shutdown the cheap energy was so they could raise their rates. Once they got there increase they called up the geothermal plants and told them to turn it on again. Now they could give their shareholders a very nice return on their investments and screw the rate payers.

[@trmon8890]

You are a genius !! I have never heard Geothermal energy explained so clearly, THANK YOU !! The mass media in the USA never covers this with experts clearly and take their experts analyst out of context. I'm looking forward to your other videos.

[@thetaomega7816]

@@simonebest6013 ok boomer

[@callum9999]

They absolutely do cover it - I just found multiple articles on multiple US media sites that explain geothermal energy in a matter of seconds. If you're hoping that this is covered on the evening news, it's not news - it's science education (hence why you're watching it on a science education channel!). This might sound nit-picky, but the blanket refusal of people to do even the most basic level of research into absolutely anything, instead only consuming what is specifically targeted at them (I assume this was in your recommended section?), is exactly why the population is so ignorant and exactly why we have people like Trump. If you only consume what's targeted at you, you're likely to just believe what you're told.

[@trmon8890]

@@callum9999 you really read to much into my commit. " explained so clearly" or ever covers this with experts clearly and take their experts analyst out of context." No where is it stated that other media outlets don't cover Geothermal energy. AND Where the hell does Trump fit into all this???

[@XH13]

150 km north of Stauffen, is Strasbourg, a French city with half a million people. Here too there was a geothermal project started in 2019. The plant caused 15 earthquakes. The last 2 where at a magnitude of 3.5. This killed the project

[@Marmocet]

Eventually, all of these geniuses are going to have to come to terms with the fact that nuclear power is the only scalable GHG emissions-free game in town. It also has the smallest death footprint of any energy technology in existence, so it's really a pretty good deal.

[@xyz.ijk.]

" ... including Pluto." Finally, Pluto gets some love ❤️. (I knew SH was the best!)

[@georgepelton5645]

Lots of good information. One thing to add would be a mention of geothermal heat pumps. They use shallow wells, or horizontal underground pipes, to recirculate liquid that pumps heat into (summer) or out of (winter) the ground. They do require electricity to operate, like air source heat pumps, but I don’t think they have the downsides of the geothermal power projects covered in this video.

[@LiveHappy76]

A few of us have commented about small, local, low- and surface-soil depth geothermal heat pumps. I helped build the Cleveland High School in Rio Rancho, New Mexico. They buried coils of plastic pipe just feet under the athletic fields for heat pump heating and cooling and it ended up using 1/6 the utility energy of standard HVAC systems.

[@mike95826]

I used to work for a utility that built 2 geo energy plants. Within 10 years they were both closed and dismantled. There are two major problems with geothermal. The first is like you say, finding a source that is close enough to the surface to be economical to tap and a large enough reserve to make it last. The second is many of what should be good sources are extremely dirty with toxins such as sulfur dioxide that has to be cleaned before it can be used and doing that is extremely expensive. The source for the first plant pulled all the heat from the surrounding formations and slowly dried up. The second plant suffered from the massive amount of corrosion that the toxins had on the hardware. So, yes, sounds good, but much more difficult and expensive to actually implement. But reality says that it is probably still a much better solution than little windmills or solar.

[@michael-vl1mn]

Try using advanced deep, enhanced geothermal system technology using a gyrotron, or a plasma drill.

[@MervynPartin]

Excellent presentation- more problems with the drilling than I knew about. One other problem that might be worth mentioning is the depletion of the localised geothermal resources. In the 1970s, I visited the Wairakei geothermal power station in New Zealand. At the time of my visit, the plant had been running for a number of years and the steam field pressure had already dropped such that not only had new wells had to be drilled, but some of the nearby geysers had ceased to erupt.

[@bunyu6237]

This problem is caused by the cooling of the rocks also right? As the geothermal power plant take out energy from the ground

[@Marmocet]

Yeah, unless you're in Iceland or some other place that sits directly on top of a hotspot, heat extraction for geothermal energy can easily exceed the heat flux. In most places, geothermal heat is an exhaustible resource.

[@malectric]

The problem was that they only drilled until they struck steam around 600m deep IIRC. These days they drill much deeper (about 2.5km). I visited the drilling rig at the Tauhara field while they were drilling early January 2008. I wasn't supposed to be there but the foreman was most accommodating when I told him of my early history in the region. We had a good chat for an hour or so while the rig was drilling. Depletion of the shallow water was the real problem. The Wairakei borefield sank about a metre during the early production years. The water is mostly subducted seawater.

[@malectric]

@@Marmocet Taupo *is* a hotspot. It is a supervolcano. There is an enormous pool of magma below the caldera. There is no shortage of heat, just shallower water reservoirs.

[@cf453]

Here in California, we refill ours with treated wastewater.

[@yalidoletupua9530]

Honestly, this Channel is what makes KZbin relevant in these days of nonsense!! Great Job Sabine!

[@introprospector]

Generic positive comment

[@martinsaunders2942]

Thanks! It’s an interesting subject that I have often wondered why it isn’t pursued more often…Living in Tuscany, there are dozens of thermal spars around where water flows out of the ground at temperatures in excess of 40c. Also, the entire area around the Gulf of Naples is highly volcanic. I was unaware of the serious difficulties in trying to harness this font of energy though.

[@johnhough4445]

As a kiwi now in the UK I must mention that we in NZ have also put time and effort into this subject; and (aside) in earlier times (some still do) the Maori used hot springs to cook food (Rotorua). Love your delivery, Ma'am, and thank you~!

[@poruatokin]

Aaah, yes. I remember enjoying Hangi food when I visited NZ many years ago.

[@huntera123]

Love the dry humor. I have worked in a similar office.

[@lgolem09l]

Here in germany, there was a real boom in single household geothermal pumps for heating. For some reason our gas prices went up.

[@ronaldharding3927]

I've often wondered what became of this technology. When I attended MTSU in the '70s, there was projects related in heat pump technology, and there were projections that geothermal energy would save us from the situation that now exists. Steam drives turbines and heated water is easily done with heat generated close to the earth's core. I appreciate this report on something that I thought was dead due to the stranglehold carbon based fuels had on energy production.

[@lukedowneslukedownes5900]

Not only are you a scientist, but an entrepreneur for humanity. Thank you for bringing out this information to me 🙏

[@brongulus2617]

One further risk issue: geothermal energy is most accessible in exactly the same places that have the highest risk of geological activity. For example, the Puna Geothermal Venture, a geothermal power plant that since the 1980s has been drilling into the east rift zone of the very active Kilauea volcano in Hawaii, USA. In 2018 a major eruption of Kilauea destroyed much of the plant. They have since been able to resume operation, but several of their wells were overrun by lava and are unrecoverable.

[@travcollier]

I was just thinking of Puna. I used to live in Hilo, and was there in 2018... The "force quake" (on May 4) was pretty, um, interesting. USGS temporarily setup in our building (USDA-ARS) since their place was damaged. Yeah... Back on topic... It seems like lots of big geothermal projects are being setup by folks who don't really know what they are doing. It seems relatively simple, but each place is going to be dealing with different and complicated geology and there's a lot of "figuring it out" even when the folks doing it are really good.

[@Serialkoala]

As long as we call geothermal drilling Admiral Ackbaring, I'm sure it'll be fine.

[@cadfael4598]

Thanks for an excellent summary Sabine. I worked in the geothermal field for some time. The technological challenges and consequences are very real and, in addition to the ones you presented, there are also the conversion efficiencies in the power plants. EGS has both relatively low energy density in the working fluid and low conversion efficiency and deep drilling presents major challenges in both cost and technology. Ideally, to overcome the seismic risks to populations, geothermal plants would be located far from centers of population…….but then you have to deal with transmission losses and the fact that the best sites may not be where you want them to be! Also in stable continental cratons, you would have to drill very deep. The 4km deep mines in South Africa only have rock temperatures of about 60 degrees C. The hottest shallow zones around the globe are also the most tectonically active, thereby creating other risk factors with seismic icy, magma effusions etc. Recently, the Puna Geothermal Venture in Hawaii was almost destroyed by the 2018 Kilauea eruption!

[@jimurrata6785]

I just mentioned Puna, up thread... Thankfully they got all the pentane out of there before the lava reached the plant. It is back in operation now, isn't it?

[@grip2617]

Such a relief when you are not exposed to terms like "catastrophic", "shocking" or "disaster".

[@richardservatius5405]

from a well driller relative; he occasionally hits air pockets (caves) and that causes lots of drilling problems.

[@raktoda707]

By far the most The most comprehensive presentation of geothermal I have witnessed to date.Tireless research and fact checker Thank you !

[@SLYdevil]

Do these scams pay, eventually?

[@UninstallingWindows]

@@SLYdevil Probably, if they didn't, we wouldn't see these on every single video. The weird thing is that KZbin doesn't block or ban these accounts...even if you report them. Even worse, youtube sends you notifications and emails, linking to these scam accounts.

[@ricknplano1401]

Thank you. Excellent introduction to the potential and trials of geothermal.

[@shawnstangeland3011]

Am really surprised Wiesbaden doesnt have a geothermal plant.

[@xavariusquest4603]

There's a part of this being missed...geothermal for household heating. If you dig down 20 to 30 feet, in basically any part of the world, you reach a zone of standard Earth ground temp. This is generally between 54F and 59F. This becomes the source for one side of a heat pump. You can cool in summer and heat in winter. The amount of electricity used to finish the cycle is far far lower than than a heat pump outside a home. The cost is drilling the 150 to 200 foot deep holes to drive the process. The net energy savings over very efficient and traditional systems is great. I have installed them in Northern tier States. Heat costs that averaged $4000 or more were reduced to about $750. Payback time for a retro fit is less than 7 years. As a part of new construction it adds only a few thousand dollars to overall costs.

[@wally10ize]

Having had a career as a drilling engineer and geologist surrounding holes in the ground from mineral exploration, water wells, oil and gas and coalbed methane I found your presentation fascinating. Hot rocks give groundwater a greater solubility of the dissolved minerals and their origin suggests they would be highly corrosive.and make for accelerated wear and tear on equipment. Once the groundwater regime is changed it is likely seismic events will occur, probably low intensity but no guarantees.

[@grindupBaker]

Yes, I presume the seismicity would decrease with increased depth before ground alteration occurred. Humans couldn't match even within a few decimal orders of magnitude the sort of force changes on the sediments that the liquid mantle causes where it forces in so humans could only make small seismic events with a shallow epicentre.

[@justaskin8523]

Some salt mines, as the salt was removed, would slowly (maybe over months or years) collapse the "roof" of the mine and everything above it, until the surface of the ground was deformed by the subsidence.

[@robertvanruyssevelt7159]

In New Zealand about 800MW is produced from geothermal power. The first and largest plant was built in 1958. Drilling is between 1000 and 3000m. The majority of power in New Zealand comes from Hydro dams but environmental concerns militate against the building of more dams. We also have solar and wind farms as well as small fossil fuel powered plants. In order to get rid of the fossil fuel powered plants there is renewed investment in more Geothermal power.

[@growtocycle6992]

The anti hydro power lobby infuriates me, as an educated, environmentally passionate kiwi

[@pauleohl]

A lot of research went into this video. I appreciate it.

[@jerelull9629]

Years ago, I worked for a few months at a coal-fired supercritical electric power station. Talk about "hard to do"! The piping in the "boiler" had walls a good 6 or 7 inches thick. If a leak was suspected, the drill was to go into the area (outside of the boiler, of course) waving a piece of lumber ahead of you. The steam could be invisible for some feet outside of the piping yet slice the wood clean off. At the time, there was one supercritical nuclear plant which was quite efficient. It's still generating megawatts of power 24/7/365, and from what the engineers were saying about the place back then, I wouldn't hesitate to live right next door if I were given a chance. IMO, the only drawback to that would be that it's in a fairly rural, backwater area and it would take "forever" to get to the stores or entertainment

[@justinweatherford8129]

I’m surprised that you didn’t seem to cover another form of geothermal. The type where you dig horizontal trenches 6’-10’ down and lay tubing in the bottom of the trenches. The tubing is then filled with distilled water and antifreeze before being connected to a heat pump. Being connected to a heat pump can allow for discharging of heat underground during the warmer months and bringing in more heat during the winter months. The deeper the trenches are dug the more efficient the system will become.

[@gibsonj5035]

I learn so much from your videos. You cover such a wide range of subjects. I enjoy your accent and love your sense of humor. 🙂 I look forward to your videos every week.

[@bbamboo3]

My father had a "ground source" heat pump that used a conventional rural well to exploit the fact that the delta t between ground and Virginia's snow, or the hot summer as the energy source for their home. Near me, a college also uses a similar system at larger scale for their heat/cooling. While not as spectacular and less important from a climate change point of view, such systems can be cost-efficient in some local situations. Such GSHP systems typically have less corrosion issues than systems such as the Geysers in California (and yes, there are very small earthquakes near there on a regular basis....

[@gregbailey45]

GSHP systems could not, in any way I could imagine, cause an earthquake!

[@bbamboo3]

@@gregbailey45 The system at the Geysers is a utility scale geothermal power plant, not a residential system as my father had. So I agree with you that GSHP systems are safe. You can watch the USGS seismic maps and see how much activity occurs near that plant. The seismic activity is minor, we all ignore those little quakes however I worry more about the San Andreas fault system just a few miles from my house could do :-). The amount of energy produced is awesome and it's mostly a just pipes deep in the ground (actually they also re-inject recycled water so it goes both ways)

[@cuddlepaws4423]

And they say Germans have no sense of humor . Yours is so dry it is desicated . It fits very well with the English sarcasm . Plus you explain things things very well .

[@HeavyMetalorRockfan9]

Fantastic channel! Glad I just stumbled onto you, love the presentation style and thoroughness

[@PhilipRhoadesP]

Another interesting podcast including deadpan humour which always makes me smile!

[@jaythepainter1]

Your humor punctuating the ends of stories have me breaking out into chuckles whenever I watch. Who else?

[@rjung_ch]

👍💪✌

[@Hansulf]

This is the most complete video I seen on youtube on the topic and even though I considered myself to be informed I learned so many new things! Keep it up!

[@thiagomarinho333]

Fantastic channel! Easy to follow and with a balanced dose of intelligent humor. Congrats!!

[@Yaxoi]

Very interesting! If I may suggest a future topic: A look at the current state of anti-aging research would be very interesting. There seems to be some real progress, but it's sometimes difficult to separate from hype and supplements marketing.

[@chrissingleton6029]

Absolutely love your sense of humour! Great content, I learn a lot with every video of yours that I watch!

[@ZubairKhan-sp8vb]

Your work is just astonishing, it is just amazing, how many diverse topics you cover with consistency. Your channel deserves to be mainstream! The logic and research both are sound and thorough. Thank you so much for deciding to become a youtuber. I wish more sound scientists would become influencers to influence people to see the power of deep thinking and carrying out essential work!!

[@fishyerik]

Thank you for another great video! Interesting, easy to understand and funny.

[@elevatedapples]

@Derty Dango John Kallener?

[@digiryde]

So, as with most realities, the answer is "It Depends", or "It's Complicated" Thank you Sabine for your continued coverage of things that do matter. It was pointed out to me that this could be viewed as a snarky comment. Just, so it is obvious, it is not. I appreciate Sabine's methods for taking complicated situations and breaking them down. The reality is that in almost every complicated or unsolved situation, the main problems are It Depends, Its Complicated, or both.

[@VantaBlackSheep]

There’s a company that created a new drilling technique that allows for deeper, faster, cheaper drilling by orders of magnitude. I believe they came out of MIT and got funded about $40m and probably more by now. If executed, that will change the answer from both its complicated and it depends to its possible.

[@myronhelton4441]

Solar is a rip off. All you have to do is run water pipes under interstate highways to homes nearby, in the summer to get piles of free hot water heat, that can be converted tp electricity.

[@digiryde]

@@myronhelton4441 Explain, please, how will this work? Just curious.

[@myronhelton4441]

It is just a theory of mine. I just now tried to find information of on the internet, but I didnt find much. Because ot probably isnt used, there must be problem with it. A friend of mine, in his kitchen is his water heater, washer, stove, and dryer, & other stuff that gives off heat. He shuts himself up in his kitchen sometimes to save energy.

[@digiryde]

@@myronhelton4441 Hypothesis are great. What are your evidence/observations that led you to this idea? Trying to draw conclusions from observations (forming hypothoses) is an important part of life. Most people just forget to do the second part, testing and having others pick those hypothoses apart.

[@IamPreacherMan]

First of all, I love your videos. My takeaway on geothermal energy is that the focus should be on really large industrial scale facilities that are far away from cities where the potential earthquakes caused by these operations can be minimized and small scale operations that can power a single farm or house or other smaller type operations that are isolated from other utilities. I do think diversification of energy needs, just like food sources, is strategically the right move for humans as a species tho. But I think the main issues with energy over the next 100 years or so will remain and revolve around distribution and storage.

[@HxTurtle]

yes, diversification is the clear trend and way to go. couldn't agree more with that. it's way more failsafe. but that also includes that you shouldn't entirely rule out established sources just because they're considered "dated" now (it might be possible to develop them further to better deal with their negative side effects); but that's only a sidenote. even within the very same tech, diversification is advantageous. like as seen in France where too many nuclear power plants from the same build suffer from the exact same issue. it's more economical to streamline everything into one single design, but the result is also more error prone. have a nice day!

[@Nill757]

@@HxTurtle “as seen in France”? French sabotaged their own nuclear fleet. There was no design flaw. EDF deliberately took vast nuclear revenue from routine maintenance budget, for years now, and gave it to other intermittent sources of power, because money is made in building new things even if useless, and not in keeping an affordable nuclear fleet running stably for decades.

[@Nill757]

There is no storage to, say, get through winters and the rest. The results are in and we know what happens with big intermittent power: fossil fuels, gas pipelines to Russia and coal plants turned back on. All this is hidden by ridiculous talk of green blue brown hydrogen. Get serious, build nuclear. We know it works, several times over now.

[@HxTurtle]

@@Nill757 oh, I see. where you from, of I may ask? I'd be very interested in learning more. I can only say what my local radio told me. it's kinda eerily similar to a video Sabine already did about nuclear fusion where a pipe suffered from corrosion. the interview with an EDF maintenance engineer said about the following: one pressurized pipe conducting radioactive cooling water showed signs of corrosion discovered by a planned routine maintenance. now they aren't sure as to whether all similar reactors suffer from the same issue. back then, metal pipes have been the only economic option. nowadays, they could also economically feasible made out of GRP (with the help of fairly recently developed click technology.) and the other thing I've learned from that interview that there was zero technical reason to reduce the power output during the (dry) summer. it was only to stay within a rather arbitrarily set limit of how much the river water can be heated up after it passed the plant (which was set to half a centigrade, iirc.) that's only so that fish don't get irritated too much when they swim around. but compared to the Oder incident, that's probably not the worst imaginable, I think. anyways, lemme know anything that you know because that's all quite the mystery, I think. I mean, F24 initially reported that due to the outage of Russian gas supply, they initially planned to maintain like half the plants prematurely during summer to guarantee full power supply during winter. they were supposed to be online again by November first, but that kinda didn't really happen. I for the longest planned to research everything a little more, but never really found time doing so. the only thing that I know for sure is that Europe would be screwed without those nuclear power plants. and that France gets very happily bashed by all other European countries for not building enough wind and solar power like defined by the European Union, yet never mention that this would increase their greenhouse gas emissions because every wind and solar plant must be backed by a conventional plant like gas to compensate for their only erratic power production. hope that wasn't too long a reply, lol. cheers!

[@HxTurtle]

@@Nill757 only now opened your other post. yes, nuclear is the most sensible option for a base load. my other post in here wasn't meant to be against nuclear, just that to diversify their design and build different types helps with not having to shut them down all at once should there be a design flaw (which never can't be ruled out. that's kinda like the root idea of diversification: you aren't totally screwed when something goes not as expected, but only a little bit.)

[@timothyvincent7371]

Some decades ago a new government office building in my hometown was designed to use pumped groundwater with heat pumps for the both heating and cooling. Not really geothermal but ground- coupled, should have been quite efficient. Trouble was, the water was so corrosive it quickly ruined all the equipment.

[@executivesinmotion1839]

One of your best ever. Funny while informative. Well designed with just the right bit of wit. Congratulations.

[@belledetector]

Excellent coverage. In 20 minutes you answer all relevant questions. Impressive production value. How many people were involved in the research and production of this video, if I may ask?

[@korakys]

There were some mixups in the video between geothermal for heat use and geothermal for electricity generation. Heat gen doesn't require nearly so much of a heat gradient difference as electric turbines do.

[@daledavies2334]

In Alberta, Canada a company is using directional drilling technology to drill a couple of larger wells a couple of miles apart. Then the directional technology comes into play to drill throigh tight rock, a number of paralell horizontal runs and intersect those from the opposite direction. This provides volume at a lower flow to help not cool the surrounding rock. The warm to hot water can be used like in a refrigerator to boil another working fluid such as ammonia to turn the turbines. Once one downhole leg is in operation, more can be drilled in other horizontal directions. This could enable shutting down a leg that is cooling to recover heat from below while keeping the plant producing. No fraking involved so no earthquakes. They have an experimental ant in operation for proof of concept.

[@rakablouwildebees]

The more I watch (this channel) the more I enjoy it ... apart from science and facts explored (and unceremoniously kicked around), your sense of humor is most entertaining

[@SebaBuenoHaceMusiquitaJijiji]

The best channel on youtube

[@kassistwisted]

Thank you for your sharp information, your comprehensive explanations, and your witty humour.

[@Bommi09]

loved the explanation with humor inserted here and there quietly :)

[@qed456]

I like it when you go all engineering!

[@eddydogleg]

Did she? Through "geothermal dissolved solids" or "rock plasticity" into your favourite search engine. As long as the return fluids are only cooling enough that the solute comes out of solution at the heat exchanger, not down hole, they might be able to make deep hole geothermal economical. As for rock plasticity what will be used to case the hole that can with stand forces high enough that they can move continent and build mountain ranges. Talk to any wireline logger working in the foothills on the east side of the Rockies in the time it take to drill the well the hole has gone from round to oval. And that's at the relatively shallow deeps of 3 to 5,000 metres. Because they use off the shelf oilfield technology there a couple of geothermal project that might be viable. DEEP Earth Energy has started operating a 25-megawatt facility in south east Saskatchewan. DEEP has chosen to use brine to move heat from downhole to surface. So as a tax payer who's watch the government pore a ton of money into this project I hope has cracked the the dissolved solids nut. The second approach from Eavor Technology uses a closed loop so they have eliminated the dissolved solids problem. The down side of both of these approaches is that they are dependent on local geology and are limited to downhole temperature of about 170C.

[@kento7899]

Well, we've known for awhile that there is no panacea answer to our energy needs. It's always some of this, and some of that. Geothermal still seems promising and I hope we continue to develop it where it makes sense.

[@dvogonen]

One might question why Sweden is in second place for geothermal energy use, while there is absolutely no high temperature water sources in Sweden. The reason is the widespread use of low effect heat pumps. The heat pump pumps a non freezing liquid like alcohol in a pipe down into the groundwater level and then back into a compressor unit for heat exchange. This typically produces four times the energy (as heat) as the pump/compressor consumes (as electricity). These systems are extremely cost efficient to install if the water floor is not to far beneath the house. The solutions is especially suited for heating single family houses in cold climates, since the ground water has a steady temperature. This ought to work as well for Canada and the northern parts of the USA as it works in Sweden.

[@watchthe1369]

Vision: "Energy Reservation" solar panels or windturbines (both in some small areas) are installed on unuseable land. The intermittant source is connected to a baseload steam plant that runs off a geothermal, Molten Salt Reactor source with heat battery extension. (When there is sun/wind but no demand you melt salt to store heat for the baseload steam turbine). If a series of cluster bomb/ Tornado, Hurricane, 'quake takes out your stuff above ground you have the geothermal and reactor to keep things hobbling along. In a WIND reservation, build the kilometer high turbines that use atmospheric flow. That leave you space under them to run the methane bioreactors that process the sewer sludge into heating gas. As you go the mulch can go out to help farmers or stay on property to regenerate the land into a sustainable hardwood/ fruitwood/ fuelwood orchard forest under the windmills. In time you would have the ability to build high quality hardwood furniture and have a heat source stored up from the scraps which are pyrolyzed into syngas and charcoal. The syngas working to make steam for the electrical generation. The charcoal and leaked products would be environmentally friendly "Neutral" carbon and solids that the environment already handles from forest fires. (the charcoal could be either stockpiled or sold for various commercial/domestic uses. In a SOLAR reservation, build the vertical panel variety that is easy to maintain and plant rapeseed, soybean or other source for biodiesel processing sources. Then exploit those synergies much like above. Using conveyors to move the dry bulk is probably cheaper carbonwise than a fleet of trucks dashing about a bunch of non-consolidated facilities. I am waiting for the greenwash and virtue signalling to stop, and for someone with the deep pockets to develop one of these by buying up land on the leward side of a stripmine and rehabilitate the land. Something a coal mine might want to evolve into since it would be looking forward to the day coal generation just went away? Maybe convert that coal plant they feed into the ceothermal/biofuelled concept as they develop a Osage Orange forest on top of the old stripmine to fuel the plant on something carbon neutral, but almost as power dense as coal?

[@themacker894]

The humor is off the wall in this episode! You're on fire!

[@Fragaut]

0:51 What happened in Staufen? Gypsum happened? Let's see how it plays out... 16:52 Nailed it...

[@traiecto]

Love the quiz. An added bonus for another great video

[@alankott3129]

Thank you Sabine. Your videos are always informative.

[@PD55_]

Excellent, informative. I always thought a hole in the ground was just a hole. Also make you wonder about the true damage of oil/gas fracking, which might be a lot worse than is commonly acknowledged.

[@EnglishMike]

The damage caused by earthquake inducing fracking has been under close scrutiny for quite some time already. I don't think it's something that's flying under the radar.

[@4draven418]

Thank you for this very enlightening video on geothermal extraction problems. I often wondered why more wasn't being done but now I know.

[@seanc1898]

Loved your video, both the knowledge and your sense of humour. Well done! 🙏

[@ggdaddy6676]

Great job on this, Sabine! Thank you!

[@DracoDatura]

Oh, I was just thinking about this the other day, thanks for the insightful video! I hope in the future this technology will be expanded to be a viable alternative in suitable locations. Even in small scale it can help towns. For example the buildings and greenhouses of the Hungarian National Botanical Garden together with the government buildings of the surrounding small town are heated by a geothermal well.

[@Namdor2012]

Dear Sabrina, How about drilling a decent hole and placing a steel pipe with a U-shaped circulation pipe inside? This would allow for the circulation of clean treated water in and steam out. Given my experience with boilers, it's important to treat the water to prevent scaling in the circulation pipe. To optimize heat transfer, it may be beneficial to use a high-quality thermal material or metal for the inner layer of the outer pipe that comes into contact with the circulation pipe. Also you could monitor the heat, shut it down periodically as not to overdraw heat from the surrounding rock, then restart the process once the surrounding rock recuperates..Hence not creating earthquake type of probs..

[@PacoOtis]

Extremely educational and excellently presented! Thanks for sharing and the best of luck.

[@thorfritland4177]

Working as a senior research engineer for a major drilling fluid supplier, I developed from scratch a temperature simulator for estimating the lifespan of a Geothermal well and downhole temperature estimation. Main conclusion the lifetime for a geothermal well rounds about 20 years.

[@thetalkinganvil8366]

Now that's a truly exceptional episode. I've always thought Geothermal to be sorta the future but wasn't aware much of it's baggage. And while I can see more merits why people might avoid it, like you, I feel further study will only bring positive results.

[@rhoddryice5412]

The table at 4:47. Most of the Swedish geothermal energy produced is single house geothermal heating with heath wells of only 100-200 meters.

[@9873459872134234]

Yes, her neglect of even acknowledging ground source heat pumps (geothermal HVAC) makes everything in this video woefully incorrect, actually. It is the single most common utilization of geothermal energy potential.

[@christianmontenegroaraya1888]

An amazing information. Very good work!

[@rand49er]

Thank you, again, Sabine, for providing a broad analysis of the current state of geothermal energy and your take on its prospects for the future contribution to humanity's energy needs. I look forward to your next video.

[@louishannett356]

I appreciate the presentation and the problems that are involved with the drilling. I was at Krafa in Iceland and that was the first geothermal site that I worked. Later I was at the Geysers project and the Salton Sea project in California. One issue at those sites is that the steam from the ground is corrosive and the turbine blades are made with Titanium to withstand the corrosion. Even still with the titanium blades there is the next turbine rotor on the generator floor.

[@denysvlasenko1865]

Why not run this water through thermal exchanger to boil clean water and use *it* in the turbine (a-la PWR reactors - they don't send reactor water to turbines)

[@louishannett356]

@@denysvlasenko1865 That may be a good idea to preserve the turbine blades. What happens to the thermal efficiency with the heat exchange? The steam coming from the ground has a temperature of about 400degF and pressure of 70 to 90psi.

[@kimollivier]

@@denysvlasenko1865 because you need Primary Energy to run a turbine - lots of superheated steam, not hot water. It is not just a central heating system. I have seen a 9 MW steam bore being tested by just opening the valve. It is very impressive. You cannot put it through a heat exchanger. Yes they remove some minerals and dry the steam but there is still carbon dioxide, sulphur and other heavy metals dissolved in the mixture. Silica precipitates out as the pressure and temperature is reduced, coating everything until it blocks.

[@louishannett356]

@@kimollivier I like your reply. What I quoted about steam conditions is superheated steam above the saturation line in a Mollier diagram. When I was in Iceland, the feeling about extracting steam from the ground was that they prefer using it for central heating over electric power generation.

[@pacificatoris9307]

Such a witty and good writing, plus all that good old sciencey stuff.

[@sabofx]

Thank you Sabine! I've been wondering about this..

[@pjimerson]

Thank you Sabine. This video is remarkably informative and I find you personally, entirely believable. It's so rare for me to find myself responding to a video with "damn, I didn't know that," and I was doing that constantly watching this video. I am not one to give my trust quickly ... many videos about energy sources and the future of energy feel biased to me. The topic seems ripe for corruption but I do not get that impression from you nor from this video. You are a gem. A keeper. Carry on is all I have to say ... it's my highest honor. :-)

[@TheBrookeClevenger]

Thank you again for your delightfully informative presentation. Always a pleasure to hear the news from you.

[@ericvanvlandren8987]

Great survey of the topic! Thank you.

[@VoltaireVoltaire-zq4zh]

You are apparently unaware of how geothermal energy is mostly used: not to produce electricity but just as a source of heat for urban heating; the hot water (between 55 and 70°) in pumped and circulated to buildings where heat exchangers are used to heat the water of the building; the colder water from the well is then re-injected into the ground water table at a certain distance from the pumping site. A water site has a certain amount of energy potential for a number of building, and as long as do not exceed the hot water table energy capacity, the cycle is infinite. In our city in the Paris region, this is used to heat about 12000 equivalent housings and represent about 65% of the energy necessary for heating (you still need to complement the geothermal energy with another source for when you do maintenance and when it is really cold). With the recent increases in gaz price, savings are huge.

[@thomasrice4078]

You do a wonderful job in explaining these concepts and problems.

[@WobblycogsUk]

Geothermal is great, right up to the point where you have to dig the hole. I hope we work on improving the technology but there are so many difficult problems it's hard to see how it'll make much of a contribution.

[@eitantal726]

My question is, what are the running costs after you drill the hole? Do you have to drill once, and it will work for 500 years? or is it more like a wind turbine, that after you build it, it only lasts ten years, and is a net negative?

[@Kerostasis]

@@eitantal726 Per the last segment of the video, that appears to be heavily dependent on earthquake conditions. If the specific hole you've drilled becomes an earthquake catalyst, the earthquakes will eventually destroy enough of your equipment that you need to re-drill and rebuild, apparently on time scales as short as 10 years. But if this hole is not an earthquake catalyst, it can last an extremely long time, to the point that no existing installations are old enough yet to test the maximum age.

[@WobblycogsUk]

@@eitantal726 I sense you may not be approaching this with an open mind but anyway. As long as the hole remains good you can keep tapping power from it. I recall reading that you have to limit the amount of power you take as you can create a cold zone that ends production permanently, that might have been specifically for Icelandic facilities that were trying to get close to magma though. Either way, earthquakes damage the hole and eventually it needs to be re-drilled. Some areas are more seismically active than others.

[@varunahlawat9013]

Amazing content every single time; I'm a big fan of this channel!

[@marqbarq5977]

As an American, I’ve never been so thoroughly educated, embarrassed (because it’s true) and entertained at the same time. Subscribed!

[@alainbergeron1675]

From Montreal Canada: Sabine, I love your channel, I think you share with us great content and you put your sarcasm on top, it's great! I don't have a science background, more eng., but I love it! :) Thank you.

[@jwrosenbury]

It's likely some of the earth's heat comes from tidal energy.

[@MaGaO]

For small values of _some_

[@roberttradd1224]

Thank you so very much for sharing this. I've learned much from your presentation ( although its been awhile since I have heard an "eyebrow: reference) i will check out Brian channel. Thanks again 😊

[@dennisfahlstrom2515]

It is not necessary to tap into high pressure, high temperatures steam several thousand feet down for geothermal to work and save the consumer money. Just burying a series of pipes that runs several hundred feet horizontally at 6’ below the surface can act to dissipate heat in the summer and allow your compressor to create cheaper AC by beginning the cooling cycle from 55 degrees F instead of 90 or more degrees of the outside air temperature. In the winter it saves the compressor energy by starting the heating cycle from that same 55 degrees F instead of 30 degrees or lower air temperature. My electricity bills here in southern Missouri went from $150 per month in the summer and $190 in the winter down to under $90 and I eliminated needing propane completely in the winter as the supplemental heating source. I was using two 500 gallon tanks per year which cost me $2900 a year. This type of geothermal system completely paid for itself in 6 years and it has been trouble free. I used that saving to add solar 3 years ago and further reduce my electric bill to $30 a month which is what the basic charge is for connection to the grid. My electricity production actually exceeds my use by a small amount. These decisions are good for the environment and good for my savings. They also increase the value of my home if my heirs don’t wish to use it and decide to sell it. My neighbors with similar sized 3 bedroom homes are all paying a total of over $6000 a year for electricity and propane. My home is basically zero energy cost year after year and it is totally independent of what the electricity and propane providers want to charge and you know their rates will only go one way …and that’s up. Since I made my decisions propane has gone from 90 cents per gallon to $2.59 per gallon and electricity has gone up 40% per KWH - and it will be going up again this year. It’s a wise financial move even if you need to borrow to get it done.

[@grindupBaker]

Well done. They are talking about generating electricity though so it's an entirely different topic, they need much denser energy than needed for building heating.

[@syncacct8576]

Geothermal is easy in Iceland as the Island is literally split into halves by a tectonic plate boundary, so they do not need to go so deep. I have visited a geothermal power plant in Iceland that is open to the public and has a visitor centre. On a smaller scale, geothermal heat pumps are widely used in Finland and Sweden to produce heat for residential properties. I have 2x300m wells and a unit with 2x20kW compressors. You put one unit of energy in and get 4-5 out. The system would have been more efficient with three 200m wells, but my plot was not big enough for that. The wells cannot be too close to one another to prevent excessive cooling.

[@mkniskanen]

I have had a ground source heat pump with a 400-metre heat-harvesting circuit just ~1.50 metres (five feet) underground. The digging of the ditch was done in about six hours (a normal tractor-based digger), and covering it took a couple of hours. Three years ago, when the first pump unit was 22 years old, I decided to replace it. I used the same harvesting circuit and the same radiators and only needed to have the pump installed. The pump installation was done in less than eight hours. The 8 kW output pump cost me ~€6500 installed and will serve us for at least 20 years. My son has a ground source heat pump 300 km north of the Arctic circle, and it has been working flawlessly for years. Unlike our pump, it has a 160 metre well, though. Just like you said, the efficiency factor is around four in the current pumps. Buy one kilowatt and get four more from the ground for free. The maintenance costs have been very low. During the 22 years of the old pump, I only needed to add some more ethanol-based liquid to the circuit once or twice, and the service cost was less than two euros per year.