Almost everything we do that initially seems like a good idea stops being such when we start doing it at scale. Burning fuels wasn't a problem at the eve of the industrial revolution. I wonder what ecological issues will hit us globally as we scale up geothermal energy use. E.g. I've read somewhere that people putting too many ground-exchange heat pumps in a small area can cause problematic cooling of the ground. Right now it's probably only a problem for the energy efficiency of the pumps themselves, but as we scale up, I worry about unintended environmental consequences.
The first sentence of that section says that "geothermal power is considered to be renewable because any projected heat extraction is small compared to the Earth's heat content." I'd like to see some estimates on how much of that heat content is available on the depths we're drilling down to (as opposed to the contents of the whole planet); and again, trees were a renewable resource too, before the industrial revolution.
> The first sentence of that section says that "geothermal power is considered to be renewable because any projected heat extraction is small compared to the Earth's heat content." I'd like to see some estimates on how much of that heat content is available on the depths we're drilling down to (as opposed to the contents of the whole planet);
Wikipedia links to an article with more detail. The crust alone is estimated to hold enough heat to supply all of the Earth's electricity generation at current levels for about 80 million years.
The total heat content of the Earth is of the order of 12.6 x 10^24 MJ, and that of the crust the order of 5.4 x 10^21 MJ (Dickson and Fanelli, 2004). This huge number should be compared to the world electricity generation in 2005, 6.6 x 10^13 MJ.
> and again, trees were a renewable resource too, before the industrial revolution.
Trees are still a renewable resource, more so since we largely stopped using them for fuel as a result of the industrial revolution.
The point of renewables is rarely to do them all "at scale" where we're expecting that one renewable to power the entire planet.
Yes, if we try to use solar for the entire planet, we'll destroy the world trying to mine every last bit of silica. If we try and use wind for the entire planet, we'd need to build something like 6-8 million turbines, possibly causing environmental destruction on the way.
Rather, the point is to say "here's a huge vein of untapped energy, some of which could be tapped without damaging the environment and without releasing carbon."
Green energy is a mix, and extrapolating to "what if everybody did this" is rarely the right question, especially when the current alternative is "keep burning oil."
The globe has three primary energy sources leftover heat(1), radioactive decay, and gravitational drag. These adds up to 0.03% of the 173,000 TW of solar power. However, 51.9 TW is greater than the entire energy demand projected to be 27 TW in 2020.
Of note, heat flux increases with both absolute temperature and temperate difference. So, with a deep enough bore you could extract GW's of power for thousands of years. 2-4 mi is rather short unless your tapping heat over a large area.
(1)Leftover heat is currently "100 billion times annual world wide energy demand" so this really can be considered 'renewable.'
PS: ~52 TW / 196.9 million miles = 264w/square mile on average. However, energy is not spread anything close to evenly.
The same thing has occurred to me about wind. I don't know the numbers, of course, but it seems like there is a scale at which the wind no longer has energy it needs to do windy stuff
Good points, but trees were a primary energy source before the industrial revolution. When fossil fuels like coal replaced trees for cooking and heating, trees began to return to the landscape. Some areas of the US are more forested now than they were in the 19th century, also due to more efficient agriculture.
We have a fair bit of geothermal energy/heating in my local area. I've always assumed that it is exchanging heat from underground, heat comes up and cool goes down. The cooling is slowly seeping out through the rock into the magma causing it to solidify. This solid spike of rock now grows as the geothermal exchange continues, the spike grows into a sail, a giant rock sail poking down into the slowly moving magma. Eventually the magma current pushes against the rock sail which is attached to the town above causing the whole lot to flip over like an iceberg.
The heat flux is the important bit, the regions below the extraction zone will be hotter and continue to push heat into the extraction zone. So it only matters if enough heat flows into the extraction zone to make up for the increased heat being taken out (vs the normal rate).
One of the most developed power plants ran out of steam before it ran out of heat.
We came very close to making whales extinct using their blubber for oil lamps. That changed in the mid 1800s when they first kerosene from petroleum. They would dump the gasoline by product into streams in Pennsylvania. The oil business almost went belly up when the light bulb was invented.
We already have geothermal cooling in the northeast. The very rich in New England drill holes into the ground and send the house warm air into the ground at one hole and then return air for another hole. Works unbelievably well. I can't tell you why but it feels like cool mountain air and not just A/C.
I really hope this works. It could be a huge answer to LARGE areas that require heat.
An open-loop geothermal is based on a standard drilled well where it pumps water up from the bottom of the well and passed through a water-to-air heat exchanger (heat-pump) and uses it to heat in the winter/cool in the summer. Water is returned to the top of the column ... about 10% is bled off to bring in fresh water.
Wells are typically your standard artesian well drilled down to 400' to 600', the geothermal needs about 12 GPM or more to be effective. If there's not enough water flow, a closed loop system can be used where a "coil" is placed in the well and the well is filled with a bentonite grout. Those are interesting because they can use glycol to run to temps below freezing.
In New England these things are very effective. The issue is the cost. The wells typically cost about $10-15K to drill, I think you get about 1-ton of cooling/heating per 100' on average.
Also, there is a large (and unnecessary) premium on these ... there's just no reason why they should cost more than a regular forced air system (aside from the well drilling, but many people in rural areas in NE have artesian wells anyway). The heat-pump units are comparable in cost to a high efficiency gas boiler ($5-8K).
Most geothermal systems have the air go thru a heat exchanger of some kind and energy transfer with the Earth happens via a much more conductive medium, like anti-freeze liquid. This isn't limited to the very rich either, its as common as installing solar panels.
EGS is a very promising technology. Currently, geothermal energy is better considered hydrothermal energy as hot water in abundance is required to turn the turbines in generators, or by heating fluids w/ lower boiling points to turn the turbines. However, there are a lot more regions with sufficient heat but insufficient groundwater circulation (because they tend to be in relatively impermeable igneous rock, and often in arid regions) that EGS will unlock if it becomes competitively priced (which it should with more technological refinement).
One of the most advanced test sites is happening now by a joint DOE/University/private collaboration at Newberry Volcano west of Bend, OR http://www.newberrygeothermal.com/
I think there is a lot of room for investment here. Geothermal is, in general, a relatively safe, secure and environmentally friendly method of power generation (the biggest concerns are in dewatering hot springs, which are beloved if not held sacred by locals). EGS may potentially have some similar wastewater issues as fracking, although not to the same scale both due to smaller volume and the lack of a need for nasty surfactants to get organics to desorb from rock. But it's generally not viewed as a viable large-scale technology in the press or more superficial energy analyses.
A hundred miles south of Newberry is OIT, a state tech school. The whole campus has been heated/cooled by Geothermal for decades (including outside sidewalks) and in the last decade, they built a 2MW geothermal power plant, and 2MW solar plant. They sell excess electricity (and hot water for heating) to the hospital next door. http://www.oit.edu/sustainability/clean-energy
NZ does a lot of geothermal so i know a little more about it than most but i'm no geologist. couple points - first, don't confuse depleting the ground water with depleting the heat. a lot of geothermal taps the heated groundwater and yes, you can screw that up by extracting more than is re-plenished. luck/geology is your guide for what the ratio is though. binary systems fare better as you pull the water out, suck off the heat and then inject the liquid back in. secondly, the big problem with geothermal is that the wells cost 10s of millions of dollars. the financial decisions far outway the technical ie, you have to spend $30-40M to get a well that's active upfront but it may take decades to get it paid back. hot dry wells are like throwing money into a pit and then paying someone else to burn it. if you're relatively small then you can eliminate this risk by running your own fluid up and down but remember these wells are only 20-30 cm in diameter. oh - and don't forget that if you mess it up, presurised ground water or mud will use your well to get through an impermeable rock layer and into an aquifer. there's some well head in Indonesia that's been pumping out cubic km's of hot mud for the last 20 years...
This is what enhanced geothermal systems (EGS) are all about: Pumping external water into hot, dry systems. Most of the work is focused on either opening natural fractures or creating new ones between an injection well and an extraction well, so the volume of rock in which heat is extracted is much larger.
Asimov in his novels had Trantor, the planet girding capital city largely extracted it's energy from geo thermal sources. In his novels, they would bury heat exchange rods to tap this power.
Interesting to see this potentially close to fruition. Now if only all roofs, roads and windows could extract solar power...
We literally live on a ball of molten iron and we've barely tapped this potential. If anyone wants free energy it's down there, bubbling away, just waiting to be harnessed.
This sounds great, my biggest concern would be that it's basically the same mechanism as "fracking," but likely minus some of the more esoteric chemicals and the sand.
What are the chances of this having similar seismic impacts with the injection of water at those depths - is there already a significant amount of water down there so the net effect would be replacement of the increased volume of the system's interior? Is the nature of the area involved such that adding water is going to lubricate existing fault lines?
Part of the concern with this is whether we're going to start seeing a significant volume of earthquakes in areas where building codes don't and haven't traditionally required the kind of safety features found in more seismically active areas.
Man I wonder what drill rig they are using for the holes!? 2 to 4 mile is roughly what? 3 to 6.4 km or so. That's a mighty deep hole! I have worked as an offsider on a prototype deep hole surface core rig and our deepest were 1600 metres and they took ages to drill!(I heard stories of the rig drilling 2.5+ holes earlier in its life) The complications you start getting down hole at those depths are pretty weird,the ground can chew bits in 10 metres. Which then take 24 hours to change.
Also wonder what gauge the holes will be, I assume they will leave them cased with the rod string but christ they can't be planning to drill HQ that deep could they? Maybe even 8 inch for the first leg? Anyone seen anymore hardware details?
This might be an incredible way to generate cheap energy. I lived in a remote location called Manikaran in Himalayas in India. It is a small town with limited resources but has an incredibly hot water spring. The locals have built pipelines that connect all major establishment with this boiling hot water which is then used to cook, soak and simply bath or heat up rooms.
The motel like place I stayed in had created an exposed pipe network in the room which emitted heat from this water. Don't want heat ? Just close the tap. Less heat turn the tap a little bit :D
You may have missed the point of this article. The northeastern United States is very geologically stable, so any geothermal energy would have to come by going very, very deep underground. We don't have any hot springs around here. So even if this project works out and eliminates a lot of future carbon emissions, it will hardly be considered cheap.
Very interesting! I just read about a Finnish geothermal project in which they are drilling two 7km (4.35 miles) deep holes to test feasibility of geothermal energy in areas which do not have naturally occurring geothermal sources close to ground level. It is a serious attempt to produce geothermal energy, and made possible by recent advantages in drilling techniques. They have now reached a depth of roughly 3.5 km.
The ground below about 6 feet remains at a constant 55 degrees year round. If you make use of that as a heat source/sink, you can cut about 30% off of your HVAC bills. I wonder why more people don't do that, especially with new construction, when it can be installed cheaply.
There are similar (research) projects going on in Europe as well. One in Finland is also drilling to get about 4 miles deep[1]. I believe some recent news (that I couldn't find) have said that the project has been progressing ok.
I predict once we have lasers powerful enough to do laser drilling then This will really take off. You'd just be paying the cost of electricity to drill and if the laser is in orbit you could quickly drill power plants all over the earth.
I'd be curious how much power is required to vaporize soil and rock.
If you're in the US I imagine you'd talk to the EPA. Anything you might do that could potentially harm others or their property has to get approved by one government agency or another. Heck, most things that wouldn't have to be too.
There are living ecosystems underground too. Worms have been found at 1.4 km depth and microbes down to 3 km underground. We are probably destroying ecosystems we don't yet understand.
For a little background on geothermal, keep in mind that while the amount of energy stored in heat within the Earth is indeed vast, it's also extremely hard to make use of generally.
One of the things that I find interesting about physical science is how many similarities there are between things that flow of very different types. In this way, making power from heat is very much like making power from water. We cannot make power from water just sitting around somewhere, no matter how high or low; we can only make power by allowing it to flow from somewhere high to somewhere low and tapping that flow. And for practical purposes, we need flow that has a certain minimum pressure and volume to be able to convert it electrical power in a cost-effective way.
Heat works the same way. There may be a tremendous amount of energy in something very hot, but the only way to use it, convert it into power, is to allow it to flow to somewhere cooler, and tap that flow in a way similar in concept to a water turbine. And just like the water turbine, the heat flow must have a certain temperature difference and rate of flow to be converted into electrical power in a cost-effective way.
Unfortunately, geothermal is terrible at this over most of the Earth's surface. The heat gradient between the hot lower levels of the crust and the surface is so long and gradual that it's effectively impossible to make electrical power from it. It's kind of like trying to extract energy from a flowing stream that's thousands of miles wide, but only a centimeter deep and flowing at barely a trickle. The total amount of energy associated with that flow is enormous, but it's so diffuse that it's difficult to tap.
Note that these guys are planning to use it for heating buildings. That's much easier, as water coming out at 120-150 degrees F is perfectly fine for that. It could potentially save a bunch of energy versus electrical or gas heating, assuming they can pipe it around without losing too much heat. But making electricity effectively requires getting the water hot enough at moderately high pressure to make steam to turn a turbine with. You can play games with exotic working fluids and such to try and get something from lower temperature differences, but it's probably impossible to run a plant at market electricity rates like that.
If we ever want to make really big amounts of energy from geothermal, I haven't really run the numbers on it, but I suspect we'd need to tap into heat below the actual crust, just to get the heat replenishment rate from the mantle high enough. We'd definitely need to be able to drill and maintain holes that deep, and then run some sort of working fluid down to the bottom, let it pick up heat at a multi-gigawatt rate, then pipe it back up to the surface without losing too much of the heat. If we ever figure out how to do that, then we'll have essentially all the power we could ever use in about the safest and least-interfering way I can imagine.
[+] [-] TeMPOraL|9 years ago|reply
Wikipedia seems to have only basic numbers up:
https://en.wikipedia.org/wiki/Geothermal_energy#Renewability...
The first sentence of that section says that "geothermal power is considered to be renewable because any projected heat extraction is small compared to the Earth's heat content." I'd like to see some estimates on how much of that heat content is available on the depths we're drilling down to (as opposed to the contents of the whole planet); and again, trees were a renewable resource too, before the industrial revolution.
[+] [-] dpark|9 years ago|reply
Wikipedia links to an article with more detail. The crust alone is estimated to hold enough heat to supply all of the Earth's electricity generation at current levels for about 80 million years.
https://web.archive.org/web/20100308014920/http://www.iea-gi...
The total heat content of the Earth is of the order of 12.6 x 10^24 MJ, and that of the crust the order of 5.4 x 10^21 MJ (Dickson and Fanelli, 2004). This huge number should be compared to the world electricity generation in 2005, 6.6 x 10^13 MJ.
> and again, trees were a renewable resource too, before the industrial revolution.
Trees are still a renewable resource, more so since we largely stopped using them for fuel as a result of the industrial revolution.
[+] [-] SamBam|9 years ago|reply
Yes, if we try to use solar for the entire planet, we'll destroy the world trying to mine every last bit of silica. If we try and use wind for the entire planet, we'd need to build something like 6-8 million turbines, possibly causing environmental destruction on the way.
Rather, the point is to say "here's a huge vein of untapped energy, some of which could be tapped without damaging the environment and without releasing carbon."
Green energy is a mix, and extrapolating to "what if everybody did this" is rarely the right question, especially when the current alternative is "keep burning oil."
[+] [-] Retric|9 years ago|reply
Of note, heat flux increases with both absolute temperature and temperate difference. So, with a deep enough bore you could extract GW's of power for thousands of years. 2-4 mi is rather short unless your tapping heat over a large area.
(1)Leftover heat is currently "100 billion times annual world wide energy demand" so this really can be considered 'renewable.'
PS: ~52 TW / 196.9 million miles = 264w/square mile on average. However, energy is not spread anything close to evenly.
[+] [-] menacingly|9 years ago|reply
[+] [-] keithly|9 years ago|reply
[+] [-] monk_e_boy|9 years ago|reply
[+] [-] maxerickson|9 years ago|reply
One of the most developed power plants ran out of steam before it ran out of heat.
https://en.wikipedia.org/wiki/The_Geysers
[+] [-] zappo2938|9 years ago|reply
[+] [-] wyldfire|9 years ago|reply
Can the planet maintain homeostasis if we remove many terawatts of energy from it?
[+] [-] wokky|9 years ago|reply
[+] [-] jcoffland|9 years ago|reply
[+] [-] unknown|9 years ago|reply
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[+] [-] baldfat|9 years ago|reply
I really hope this works. It could be a huge answer to LARGE areas that require heat.
[+] [-] lsllc|9 years ago|reply
Wells are typically your standard artesian well drilled down to 400' to 600', the geothermal needs about 12 GPM or more to be effective. If there's not enough water flow, a closed loop system can be used where a "coil" is placed in the well and the well is filled with a bentonite grout. Those are interesting because they can use glycol to run to temps below freezing.
In New England these things are very effective. The issue is the cost. The wells typically cost about $10-15K to drill, I think you get about 1-ton of cooling/heating per 100' on average.
Also, there is a large (and unnecessary) premium on these ... there's just no reason why they should cost more than a regular forced air system (aside from the well drilling, but many people in rural areas in NE have artesian wells anyway). The heat-pump units are comparable in cost to a high efficiency gas boiler ($5-8K).
EDIT: Add info on "bleeding" the well.
[+] [-] reza_n|9 years ago|reply
[+] [-] NegativeLatency|9 years ago|reply
The most recent "This Old House" series used a geothermal system. http://www.pbs.org/video/2365733023/
[+] [-] dTal|9 years ago|reply
Could it be because A/C incidentally dehumidifies the air, while this method doesn't?
[+] [-] dougb|9 years ago|reply
[+] [-] unknown|9 years ago|reply
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[+] [-] 1_listerine_pls|9 years ago|reply
[+] [-] cossatot|9 years ago|reply
One of the most advanced test sites is happening now by a joint DOE/University/private collaboration at Newberry Volcano west of Bend, OR http://www.newberrygeothermal.com/
I think there is a lot of room for investment here. Geothermal is, in general, a relatively safe, secure and environmentally friendly method of power generation (the biggest concerns are in dewatering hot springs, which are beloved if not held sacred by locals). EGS may potentially have some similar wastewater issues as fracking, although not to the same scale both due to smaller volume and the lack of a need for nasty surfactants to get organics to desorb from rock. But it's generally not viewed as a viable large-scale technology in the press or more superficial energy analyses.
[+] [-] briffle|9 years ago|reply
http://www.oit.edu/orec/geo-heat-center
[+] [-] jgamman|9 years ago|reply
[+] [-] cossatot|9 years ago|reply
[+] [-] sfifs|9 years ago|reply
Interesting to see this potentially close to fruition. Now if only all roofs, roads and windows could extract solar power...
[+] [-] astrodust|9 years ago|reply
[+] [-] fencepost|9 years ago|reply
What are the chances of this having similar seismic impacts with the injection of water at those depths - is there already a significant amount of water down there so the net effect would be replacement of the increased volume of the system's interior? Is the nature of the area involved such that adding water is going to lubricate existing fault lines?
Part of the concern with this is whether we're going to start seeing a significant volume of earthquakes in areas where building codes don't and haven't traditionally required the kind of safety features found in more seismically active areas.
[+] [-] gtvwill|9 years ago|reply
Also wonder what gauge the holes will be, I assume they will leave them cased with the rod string but christ they can't be planning to drill HQ that deep could they? Maybe even 8 inch for the first leg? Anyone seen anymore hardware details?
Edit :fix phones autocorrect.
[+] [-] tn13|9 years ago|reply
The motel like place I stayed in had created an exposed pipe network in the room which emitted heat from this water. Don't want heat ? Just close the tap. Less heat turn the tap a little bit :D
[+] [-] rm_-rf_slash|9 years ago|reply
[+] [-] dirtyaura|9 years ago|reply
There's not that much about the project in English, though. Here is a short video interview https://www.youtube.com/watch?v=n853GBQocC4 and a short article http://www.thinkgeoenergy.com/finnish-40-mw-district-heating...
[+] [-] WalterBright|9 years ago|reply
[+] [-] unknown|9 years ago|reply
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[+] [-] realkitkat|9 years ago|reply
URL: http://www.st1.eu/news/st1s-geothermal-heating-project-appro...
[+] [-] mrfusion|9 years ago|reply
I'd be curious how much power is required to vaporize soil and rock.
[+] [-] cossatot|9 years ago|reply
[+] [-] xkcd-sucks|9 years ago|reply
[+] [-] dimino|9 years ago|reply
For example, what if I wanted to modify the atmosphere for an experiment I'm running, who do I talk to about that?
[+] [-] amaranth|9 years ago|reply
[+] [-] test_pilot|9 years ago|reply
[+] [-] ufmace|9 years ago|reply
One of the things that I find interesting about physical science is how many similarities there are between things that flow of very different types. In this way, making power from heat is very much like making power from water. We cannot make power from water just sitting around somewhere, no matter how high or low; we can only make power by allowing it to flow from somewhere high to somewhere low and tapping that flow. And for practical purposes, we need flow that has a certain minimum pressure and volume to be able to convert it electrical power in a cost-effective way.
Heat works the same way. There may be a tremendous amount of energy in something very hot, but the only way to use it, convert it into power, is to allow it to flow to somewhere cooler, and tap that flow in a way similar in concept to a water turbine. And just like the water turbine, the heat flow must have a certain temperature difference and rate of flow to be converted into electrical power in a cost-effective way.
Unfortunately, geothermal is terrible at this over most of the Earth's surface. The heat gradient between the hot lower levels of the crust and the surface is so long and gradual that it's effectively impossible to make electrical power from it. It's kind of like trying to extract energy from a flowing stream that's thousands of miles wide, but only a centimeter deep and flowing at barely a trickle. The total amount of energy associated with that flow is enormous, but it's so diffuse that it's difficult to tap.
Note that these guys are planning to use it for heating buildings. That's much easier, as water coming out at 120-150 degrees F is perfectly fine for that. It could potentially save a bunch of energy versus electrical or gas heating, assuming they can pipe it around without losing too much heat. But making electricity effectively requires getting the water hot enough at moderately high pressure to make steam to turn a turbine with. You can play games with exotic working fluids and such to try and get something from lower temperature differences, but it's probably impossible to run a plant at market electricity rates like that.
If we ever want to make really big amounts of energy from geothermal, I haven't really run the numbers on it, but I suspect we'd need to tap into heat below the actual crust, just to get the heat replenishment rate from the mantle high enough. We'd definitely need to be able to drill and maintain holes that deep, and then run some sort of working fluid down to the bottom, let it pick up heat at a multi-gigawatt rate, then pipe it back up to the surface without losing too much of the heat. If we ever figure out how to do that, then we'll have essentially all the power we could ever use in about the safest and least-interfering way I can imagine.
[+] [-] unknown|9 years ago|reply
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[+] [-] csense|9 years ago|reply
[+] [-] BurningFrog|9 years ago|reply
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[+] [-] rm_-rf_slash|9 years ago|reply