On PBS NewsHour this evening (00:08:30):
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Geothermal energy is a good alternative but the article gave a bit optimistic view of the technological challenges.
For one house (single family), the depth of the well is usually between 180-240m. For larger units, the well needs to be deeper and/or there needs to be more wells. This technology is business-as-usual, very common nowdays here.
For commercial production, the well needs to be much deeper. Here, the deepest experimental wells were planned to be >5 km. As the depth of the well increases, technical challenges increase and the cost increases. The deepest wells were a partial failure, they did not get as much energy as calculated. I guess the rock did not behave as calculated, so the flow of water did not meet expectations. With deeper wells, it is also increasingly difficult to drill holes that are exactly vertical and stay within the calculated distance from each other. I don’t know if this was a major problem in the experimental wells.
The technology will get better but at the moment, the commercial companies are planning wells that would be only 2-2.5 km deep. When the technology works better, they will switch to deeper wells.
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I have wondered, if in our ever-growing, ravenous desire for more energy sources, what kind of damage we can do to the planet through geothermal. Right now geothermal is starting to expand. What happens “when everybody’s got one?”
I’m not trying to use a question as a rhetorical strategy to “prove” anything, but am concerned about the patterns of human behavior, unexpected consequences and new forms of self-destruction. That you know of, Is anyone doing research in this direction (that is understandable to a layperson?) Please don’t go on a research hunt for me. If there is a publication you can direct me to, that would be great. Thanks!
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I saw that. It was good.
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There is plenty of geothermal energy. Tapping to this source is not going to cool the earth.
Locally there might be some problems. The solution that circulates in the wells is not usually water. If the wells are drilled to sites that are important sources of fresh water, there is a risk of affecting the quality of fresh water. If the ground water moves between layers of soil or rock, drilling through the formation may direct the water to another route. This may drop the amount of water coming to surface through springs or fresh water wells. Less drinking water to humans and drying of moist ecosystems around springs.
If the wells are too close to each other, they cool the surroundings and give less energy. I suspect that, in the worst case, the soil might freeze to substantial depths during cold winters if there are too many wells close to each other. I do not know if my suspicion is close to the truth or not.
Deep wells may also mess with built subsurface structures and vice versa.
For these reasons, drilling of geothermal wells is regulated here. You have to apply for a permission and do not get the permission if the site is on an important fresh water source or might interfere with other subsurface use of the area.
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Knor, there’s a book that addresses long term plans like the project in Finland. Actually the Finnish project you mention is in the book: The Optimist’s Telescope, by a woman named Venkataraman. (She’s from Wooster, Ohio.)
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Kendal, what’s behind your comment?
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Our well is only 100 ft. 
(We have a water source heat pump and use domestic water for HVAC of our relatively small home, 1400 sq. ft., and the clean effluent goes to the nearby creek. The water table is very high, though, so we only have to lift it less than 10 ft.)
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Honestly, ignorance. My earth and planetary science classes were back in ancient days, and I haven’t done anything to keep them up beyond “gee whiz” popular stuff you run across sometimes. My liberal arts work in college was wonderful, but did not help in answering these kinds of questions.
Our state capitol building in Michigan (U.S.) was converted recently to geothermal, which was a huge project on a beautiful, historic building. So it is becoming more of a headline topic here.
In Michigan water issues are also a great concern. It’s our most valuable natural resource, and our lakes are freely treated as expendable (it feels that way at least). So, anything that affects water is of great interest to us. Pretty much anything that goes in the ground is involved with our water.
Finally, we are not a prime place for solar or wind. At least that’s what we hear a lot from those with interests in fossil fuels. Not enough sun. Not enough wind. But that might not be “that” true. I am seeing more and more solar farms and regularly drive past some enormous wind mill “farms” in the middle of the state. I think it depends on the interests of who you talk to, how they will evaluate the effectiveness of alternative sources of energy.
I really appreciate having the opportunity to check in with people who actually know what they’re talking about. So, thanks to you both, @boendennis and @knor.
Forgot to include this in the first draft:
http://capitol.michigan.gov/Content/Files/Capitol/MSCC-Report-October-Issue.pdf
The depth depends on the need. Here, the wells need to warm the house even if temperature drops below -30 C, although the ‘normal’ winter temperature in southern Finland is closer to -10 C. Some people with a well of 180m have had problems during cold days - difficulties in maintaining a decent indoor temperature.
Our well is about 210m and it has worked without problems.
Our neighbor is switching from oil to geothermal during this year. He will have a well of 230-240m, just to be on the safe side. He told that his brother has a well of 280m but it is used to warm a farm house.
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Well, I once read that ultimately, it is all about the money. In this case, I think it is pretty true. Despite the whining I hear about high energy prices, that is going to be the driver to new energy resources. I have a relative who works closely with the energy sector and we were talking about wind turbines. Evidently, the current tax subsidies pay the turbine guys (and these numbers are from memory, so don’t hold me to them, though the relative values are close to what he said) 15 cents a kilowatt for all they produce. Last year, the coal and natural gas companies produced electricity for about 4 cents a kilowatt. So, the wind turbine companies could bid almost 0 to provide to the consumer, and still make 15 cents per kilowatt for production from our tax dollars.
It seems there is always someone gaming the system to skim the profits. Now, if costs of production were equal, wind turbines and alternative energy sources would be more sustainable. Maybe that is the direction we are heading. Of course, if your electric bills quadruple, that will force people to conserve, to build smaller more energy efficient homes, drive less and more efficient cars, and so forth, as they need to eat.
So, to me it seems it is money (resource) driven. We can’t have cheap energy and sustainable energy both. (And perhaps with a nod to nuclear as a exception.)
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We also use it for air conditioning – cooling and dehumidification in the summer. (Our groundwater temp. is ca. 50°F, 10°C.)
Price definitely but also legislation and external conditions. Europe has just planned a very rapid jump towards new energy sources. We can thank mister Putin for it. Coal, oil and gas from Russia are currently very unpopular, especially because selling that stuff gives Russia the money they need for the ongoing war. Europe is currently financing the war of Putin…
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Knor and jam, in this case, price and doing the right thing will work together, once investors realize, as 2 examples, they’d like to have clean air and water. Thanks for everyone’s input on this topic! I hope all of you had some time to check into the conference Friday and Saturday.
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Just to return to the original topic: I read an article about the current situation in the research field of developing cleaner power storage. Published in a partly scientific magazine with the name ‘Tiede’ that means ‘Science’ - I guess a national ‘competitor’ of the partly scientific magazine Science you have but more oriented towards the general audience. The article was in Finnish, so would not help many here.
There seems to be really much going on in that research field. Almost every month someone announces a new technology or an improvement of old technology that might solve current problems. The main problem is that many promising ideas and findings prove to be less promising at the stage when the technology should reach commercial utilization. Read cautiously what the researchers announce in the media, the motivation is often just to ensure future research funding. The large-scale breakthrough of promising novel technologies might be as far as a commercial fusion reactor.
Despite the hype, technology is advancing. There are different research lines for small-sized mobile power storage and storage of wind power or other grid energy. The needs are so different that there is no solution that fits to all situations.
Currently the research focusing on the storage of wind power seems to mainly rely on flow batteries. The current large flow batteries are quite expensive because they need expensive materials, like vanadium. Development of new materials will reduce the cost, which should increase the use of flow batteries. May take some time but the prospects look promising.
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Just a quick follow up on fission energy. Youtuber Kyle Hill released a video on the risks of nuclear waste that was really well done.
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Thanis. Informative and entertaining.
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