From the article: … … If you’re thinking you’ve heard this sort of thing before, you probably have. Looking at what was shared on Tildes, there was a story in 2020. However, that doesn’t mean it...
From the article:
Geothermal capacity could increase 20-fold by 2050, generating 10% of the US’s electricity, according to a recent road map released by the US Department of Energy. Joe Biden’s administration has also funded new projects aimed at pushing forward the next generation of geothermal that aim to make the energy source available anywhere on America’s landmass, not just easy-to-reach hot springs.
…
In February, the Biden administration announced $74m for up to seven pilot projects to develop enhanced geothermal systems that, the government said, hold the potential for powering 65m American homes.
…
“Anywhere in the country, if you drill, it gets hotter and hotter with each mile you go deeper,” said Koenraad Beckers, an NREL thermal sciences researcher.
“In the western United States, that temperature increases fast. If you drill just one to two miles deep, you have temperatures hot enough for electricity. To get those temperatures in eastern states, you might need to drill miles and miles down, but you can use lower temperatures to directly heat or cool campuses, neighbourhoods and even towns.”
Dozens of new companies are looking to push ahead with geothermal plans, buoyed up by incentives offered by recent legislation passed in the US, although only a few have so far managed to complete full projects in the US, such as Eavor, a Canadian firm that successfully drilled a three-mile hole in New Mexico to prove it could access heat in deep, granite rock.
If you’re thinking you’ve heard this sort of thing before, you probably have. Looking at what was shared on Tildes, there was a story in 2020.
However, that doesn’t mean it won’t happen. After all, solar and wind took many decades to become as big as they are now.
Comment box Scope: question Tone: neutral, interested Opinion: yes, casually Sarcasm/humor: none Barring a series of revolutionary breakthroughs that make nuclear fusion truly commercially viable...
Comment box
Scope: question
Tone: neutral, interested
Opinion: yes, casually
Sarcasm/humor: none
Barring a series of revolutionary breakthroughs that make nuclear fusion truly commercially viable before the end of the century (unlikely), I see plenty of opportunity for geothermal energy. It has opportunity even in that case because of its comparative simplicity.
My question is about the fracking. I have always been made to understand, perhaps wrongly, that fracking causes earthquakes and sinkholes in some capacity. (I understand that there is conflicting research.) Is advanced geothermal’s process subject to this same issue? Or have they somehow solved the earthquake problem?
I believe the government when they say there’s opportunity here, I’m just wondering if they’ve properly considered the costs. They were way too optimistic about leaks from methane gas extraction and now it’s a major environmental hazard.
I can touch on this a bit. I'm a graduate Mechanical Engineering student focused on buildings, but work adjacent to a lot of advanced energy engineering folk. I don't believe advanced geothermal...
I can touch on this a bit. I'm a graduate Mechanical Engineering student focused on buildings, but work adjacent to a lot of advanced energy engineering folk. I don't believe advanced geothermal as it's being discussed creates the same issues as fracking in part because the holes drilled are going miles straight down rather than down a little ways and then horizontal. Additionally, once the wells are established water is just going to get pumped down and recirculated to collect the heat. As opposed to fracking which (to my understanding) uses blasts of pressurized fluid to break up the rock and release trapped oil and gas.
So with fracking, there's mass extraction from the ground (pumping out fossil fuels trapped in the rock) AND the whole process is focused on breaking rock up along a horizontal plane instead of just directly under the well head. While I'm not familiar with the current state of research on fracking related earth quakes or sinkholes, the process certainly has components that suggest it could do that.
Once established, I think the advanced geothermal wells are going to be pretty boring. There shouldn't be much pressure variation in the ground once the plant is running. Also because the hole is drilled vertically it also shouldn't disrupt the stability of the surrounding ground.
To @PetitPrince's point, these wells are so deep they should be drilling well below the water table and any aquifers. You'd probably want to pick a site that doesn't have you drilling through an aquafer but this gets too far outside my area of experience to feel comfortable speculating. It's not a heat pump for this application though. The ground is still acting as a heat exchanger, but the goal is to pump water so deep underground that the higher temperature of the earth heats it up hot enough to drive a power cycle (I think most geothermal uses Organic Rankine cycles). So the water would circulate through the ground, become super heated, and return to a heat exchanger which would transfer heat to the working fluid of the power cycle.
I think what's effectively being proposed is the creation of artificial geothermal water wells directly where we want to generate power which I think is a crazy cool idea. We may not be a space faring species yet, but tapping our planet's high temperature heat directly is a pretty advanced feat if we can pull it off. Hard not to see this (combined with renewables) as big steps in our relationship with energy.
I have residential geothermal in my home. One thing I'll tell you: the wells drilled can be of a few types: closed loop. One or more wells is drilled, and a plastic pipe with a u-bend at the...
I have residential geothermal in my home. One thing I'll tell you: the wells drilled can be of a few types:
closed loop. One or more wells is drilled, and a plastic pipe with a u-bend at the bottom is pushed through the bore hole. In this implementation, there is no interaction with the water table for day to day operation. In other words, you have a well(s) with a pipe going up and down inside of it and a water/glycol solution inside of it that facilitates the heat exchange with the latent temperature in the earth.
open loop. Wells drilled. Pipes inserted. Water is exchanged with the water table at the bottom of the well to exchange heat.
pond loop. There is no well. A coil of pipe is inserted under a decent depth of water. This is another closed loop implementation.
surface loop. This is another closed loop. But instead of drilling a borehole, and pool sized rectangle is dug up to maybe a depth of ten feet and heat is exchanged inside the soil layer.
Obviously commercial and power plant sized systems really only use the first two options.
But for me as a residential owner, the 470' 2x closed loop bore holes give me incredible efficiency and zero day to day interaction with the water table.
The end result is very little risk a-la frakking. But, of course, you are drilling two holes into the rock. In my case, it's solid granite from 7 feet below grade all the way to the bottom. I have zero concerns about messing with the water table.
Oh, and just because I was forgetting the efficiency comparisons: This all being said, whenever someone installs a heat pump to replace resistive electricity, or especially any fossil-fuel burning...
Oh, and just because I was forgetting the efficiency comparisons:
That said, in the comparison between ASHPs and GSHPs, geothermal wins on efficiency: air source heat pumps generally have heating efficiencies around 400 percent, meaning every 100 kilowatts of electricity consumed produces roughly 400 kW of thermal energy. Geothermal heat pumps, on the other hand, can reach efficiencies as high as 600 percent. As this relates to your own utility bills, you'll pay more for electricity when using ASHPs to heat your home than you would pay to heat the same space with GSHPs. Source: https://www.energysage.com/heat-pumps/compare-air-source-geothermal-heat-pumps/
This all being said, whenever someone installs a heat pump to replace resistive electricity, or especially any fossil-fuel burning utility, it's a huge win for their wallet as well as the environment.
That's what I was saying though. Some of the newest air source heat pumps meet or exceed 600% efficiency. Here's one such model. It has an HSPF2 rating of 22, which roughly corresponds to a COP of...
That's what I was saying though. Some of the newest air source heat pumps meet or exceed 600% efficiency.
That's awesome to see! Love it. Sadly I can't find that one on Goodman's site yet. Seems like maybe it's not really very available just yet. I wonder what the cost of that unit would be. Also ......
That's awesome to see! Love it. Sadly I can't find that one on Goodman's site yet. Seems like maybe it's not really very available just yet. I wonder what the cost of that unit would be.
Also ... "Cold Climate Field details: No" seems a bit concerning if it's actually going to be your whole-house sole solution here in the Northeast US!
Love to see the tech continuing to improve. We desperately need it.
Cool. 9000 BTU ... gonna need a few of those suckers to do the job! That being said, we'll see this in higher BTU and lower prices as it conquers the market. When these units are installed, if...
Cool. 9000 BTU ... gonna need a few of those suckers to do the job! That being said, we'll see this in higher BTU and lower prices as it conquers the market. When these units are installed, if you're a math-oriented person, the idea that they generate more units of heat than electricity they consume is just fucking awesome. I remember explaining it to my partner and being accused of fuzzy math.
Ripping out an 82% AFUE propane furnace that was louder, polluting, and woefully inefficient was my pride and joy. When you're talking about 400%, 600%, or 800% efficiency, we're really on the margins of "holy shit, this is so good, what does it matter". I'm so happy to see this shit growing.
Well, this is a minisplit specifically. That unit I'd expect to be absoultely no more than $5k installed. Generally only intended to do 1 room at a time, though many minisplit systems can join to...
Well, this is a minisplit specifically. That unit I'd expect to be absoultely no more than $5k installed. Generally only intended to do 1 room at a time, though many minisplit systems can join to a single outdoor unit as well. The ductless models tend to be much more efficient as they can hyper-optimize to the room that they're in. Fully central HVAC is necessarily going to be less efficient to achieve indoor comfort, it seems most of the ducted systems aren't approaching anywhere close.
I have a (now) slightly older model which gets efficiencies closer to what you state, connects 4 indoor mini-split ductless units to a single outdoor unit which totals at about 45k BTU. It only provides coverage for roughly 60% my house, but fully replaced all of the central air system (the rest of the house gets conditioned enough from circulation) and replaced 80% of the electric baseboard heaters (though admittedly the few that are left are monsters).
I'd love to see more models by manufacturers that have an established presence in typical US homes. When I went looking about two years ago for what options I had to replace my central furnace and...
I'd love to see more models by manufacturers that have an established presence in typical US homes. When I went looking about two years ago for what options I had to replace my central furnace and AC, local installers really only had one or two options through the manufacturers they worked with.
Absolutley, it's just added friction for the buyer. You still have to be pretty highly motivated to get a heat pump, which is a shame since they're the perfect answer in most cases.
Absolutley, it's just added friction for the buyer. You still have to be pretty highly motivated to get a heat pump, which is a shame since they're the perfect answer in most cases.
One thing that these headline numbers don’t capture is how the efficiency changes with temperature. It seems like if ground source is going to do well anywhere, it would be in cold climates where...
One thing that these headline numbers don’t capture is how the efficiency changes with temperature. It seems like if ground source is going to do well anywhere, it would be in cold climates where air source is less efficient?
The opposite! Ground source is more efficient in cold weather than air source as it has no outdoor components. It relies exclusively on temperature deep underground. The temperature 400' down is...
The opposite! Ground source is more efficient in cold weather than air source as it has no outdoor components. It relies exclusively on temperature deep underground. The temperature 400' down is remarkably stable over the year. And more than sufficient to facilitate the physics involved in the evaporation and condensing of the closed refrigerant.
It's sort of a true story. The tax credits for my solar and geothermal installs made more than happy to sink the cash into the costs. But, paying for all my heating and all my cooling via solar...
It's sort of a true story. The tax credits for my solar and geothermal installs made more than happy to sink the cash into the costs. But, paying for all my heating and all my cooling via solar generation is simply excellent.
For me, the calculation for a ground-source heat pump was two fold over an air-source heat pump:
dramatically higher efficiency when comparison to air-source (read: dramatic electricity cost savings for ground-source rather than air- on a day-to-day basis, forever)
recently-build home with ducting pre-installed into all the walls. This meant it was trivial to rip our the central propane and AC compressor and toss a geothermal "furnace" in the same spot, and run water-to-air geo through all the existing ducting, rather than retrofitting separate air-source heat pumps onto all of my walls internally with the compressors placed somewhere outside.
I will say, if I finish my basement in the future, I can either cut into my ducting and add a third zone on my geothermal, or add an air-source heat pump on the walls in the basement. I very well might go for the air-source so that it's completely separate and I can simply disable all heating/cooling if I am not actively using the space. Though, to the frank, it will be more cost effective to simply add a little piddly third zone to the existing system, further driving the long term cost savings of ground source even higher.
Oh yes, I 100% agree. But basically I was looking at: Spend $15,000 to install air-source minisplits. Spend $45,000 to install a geothermal system. It'd have taken over 40 years for the geothermal...
Oh yes, I 100% agree. But basically I was looking at:
Spend $15,000 to install air-source minisplits.
Spend $45,000 to install a geothermal system.
It'd have taken over 40 years for the geothermal to be cost effective for that increased efficency, especially since the ground-source incentives were not a fraction of the air-source incentives.
Totally agree! I'm so happy to see the proliferation of ASHPs in the market and in people's homes. It's demonstrable progress for our society. I'd love to see GSHPs continue to grown in...
Totally agree! I'm so happy to see the proliferation of ASHPs in the market and in people's homes. It's demonstrable progress for our society.
I'd love to see GSHPs continue to grown in prevalence, as they are more efficient. As that prevalence grows, costs will come down somewhat. But of course, realistically, ASHPs will win in the short- and medium-terms, for sure.
I'd just love to see new construction homes begin installing GSHPs as a default. If new homes had that, the economy of scale would really help the industry. That being said, new homes with all ASHPs would be perfectly fine in my book, too. We just need to stop building with propane and natural gas ASAP.
Realistically, I didn't think very seriously about ASHPs. I didn't want to wire up 4-6 of them throughout my house, and I didn't want the lower efficiency. My GSHP was $27k. installed prior to the...
Realistically, I didn't think very seriously about ASHPs. I didn't want to wire up 4-6 of them throughout my house, and I didn't want the lower efficiency. My GSHP was $27k. installed prior to the 30% tax credit.
Random non expert speculation : it's still bad. In both case you use water to break rocks, which weakens the overall structure. I assume that this is this weakening that can cause earthquakes and...
Is advanced geothermal’s process subject to this same issue? Or have they somehow solved the earthquake problem?
Random non expert speculation : it's still bad. In both case you use water to break rocks, which weakens the overall structure. I assume that this is this weakening that can cause earthquakes and sinkholes (I initially though it was replacing oil with water, but then remembered that water is more dense than oil).
Now maybe that you don't need to break as much rocks as in the oil extraction process. Then it's just a big, unelegant heat pump. I don't think heat pumps inherently poses problem (no mass exchange), though the initial drilling can (wasn't there a Tim Traveler episode about a German town that's sinking because the drilling hit an acquifer?).
I would be happy to be corrected with someone with actual expertise.
From the article:
…
…
If you’re thinking you’ve heard this sort of thing before, you probably have. Looking at what was shared on Tildes, there was a story in 2020.
However, that doesn’t mean it won’t happen. After all, solar and wind took many decades to become as big as they are now.
Comment box
Barring a series of revolutionary breakthroughs that make nuclear fusion truly commercially viable before the end of the century (unlikely), I see plenty of opportunity for geothermal energy. It has opportunity even in that case because of its comparative simplicity.
My question is about the fracking. I have always been made to understand, perhaps wrongly, that fracking causes earthquakes and sinkholes in some capacity. (I understand that there is conflicting research.) Is advanced geothermal’s process subject to this same issue? Or have they somehow solved the earthquake problem?
I believe the government when they say there’s opportunity here, I’m just wondering if they’ve properly considered the costs. They were way too optimistic about leaks from methane gas extraction and now it’s a major environmental hazard.
I can touch on this a bit. I'm a graduate Mechanical Engineering student focused on buildings, but work adjacent to a lot of advanced energy engineering folk. I don't believe advanced geothermal as it's being discussed creates the same issues as fracking in part because the holes drilled are going miles straight down rather than down a little ways and then horizontal. Additionally, once the wells are established water is just going to get pumped down and recirculated to collect the heat. As opposed to fracking which (to my understanding) uses blasts of pressurized fluid to break up the rock and release trapped oil and gas.
So with fracking, there's mass extraction from the ground (pumping out fossil fuels trapped in the rock) AND the whole process is focused on breaking rock up along a horizontal plane instead of just directly under the well head. While I'm not familiar with the current state of research on fracking related earth quakes or sinkholes, the process certainly has components that suggest it could do that.
Once established, I think the advanced geothermal wells are going to be pretty boring. There shouldn't be much pressure variation in the ground once the plant is running. Also because the hole is drilled vertically it also shouldn't disrupt the stability of the surrounding ground.
To @PetitPrince's point, these wells are so deep they should be drilling well below the water table and any aquifers. You'd probably want to pick a site that doesn't have you drilling through an aquafer but this gets too far outside my area of experience to feel comfortable speculating. It's not a heat pump for this application though. The ground is still acting as a heat exchanger, but the goal is to pump water so deep underground that the higher temperature of the earth heats it up hot enough to drive a power cycle (I think most geothermal uses Organic Rankine cycles). So the water would circulate through the ground, become super heated, and return to a heat exchanger which would transfer heat to the working fluid of the power cycle.
I think what's effectively being proposed is the creation of artificial geothermal water wells directly where we want to generate power which I think is a crazy cool idea. We may not be a space faring species yet, but tapping our planet's high temperature heat directly is a pretty advanced feat if we can pull it off. Hard not to see this (combined with renewables) as big steps in our relationship with energy.
Thanks for the writeup! This makes me more optimistic about the technology.
I have residential geothermal in my home. One thing I'll tell you: the wells drilled can be of a few types:
Obviously commercial and power plant sized systems really only use the first two options.
But for me as a residential owner, the 470' 2x closed loop bore holes give me incredible efficiency and zero day to day interaction with the water table.
The end result is very little risk a-la frakking. But, of course, you are drilling two holes into the rock. In my case, it's solid granite from 7 feet below grade all the way to the bottom. I have zero concerns about messing with the water table.
Geo was one of the best decisions I ever made.
I wanted to go Geo, but air-source heat pumps are getting so good that the upfront install costs make it harder to justify Geo.
Oh, and just because I was forgetting the efficiency comparisons:
This all being said, whenever someone installs a heat pump to replace resistive electricity, or especially any fossil-fuel burning utility, it's a huge win for their wallet as well as the environment.
That's what I was saying though. Some of the newest air source heat pumps meet or exceed 600% efficiency.
Here's one such model. It has an HSPF2 rating of 22, which roughly corresponds to a COP of 8.2, or 820% efficient.
That's awesome to see! Love it. Sadly I can't find that one on Goodman's site yet. Seems like maybe it's not really very available just yet. I wonder what the cost of that unit would be.
Also ... "Cold Climate Field details: No" seems a bit concerning if it's actually going to be your whole-house sole solution here in the Northeast US!
Love to see the tech continuing to improve. We desperately need it.
Oh yea, the EPA is basically a 'coming soon' for anything that was certified this year.
Cool. 9000 BTU ... gonna need a few of those suckers to do the job! That being said, we'll see this in higher BTU and lower prices as it conquers the market. When these units are installed, if you're a math-oriented person, the idea that they generate more units of heat than electricity they consume is just fucking awesome. I remember explaining it to my partner and being accused of fuzzy math.
Ripping out an 82% AFUE propane furnace that was louder, polluting, and woefully inefficient was my pride and joy. When you're talking about 400%, 600%, or 800% efficiency, we're really on the margins of "holy shit, this is so good, what does it matter". I'm so happy to see this shit growing.
Well, this is a minisplit specifically. That unit I'd expect to be absoultely no more than $5k installed. Generally only intended to do 1 room at a time, though many minisplit systems can join to a single outdoor unit as well. The ductless models tend to be much more efficient as they can hyper-optimize to the room that they're in. Fully central HVAC is necessarily going to be less efficient to achieve indoor comfort, it seems most of the ducted systems aren't approaching anywhere close.
I have a (now) slightly older model which gets efficiencies closer to what you state, connects 4 indoor mini-split ductless units to a single outdoor unit which totals at about 45k BTU. It only provides coverage for roughly 60% my house, but fully replaced all of the central air system (the rest of the house gets conditioned enough from circulation) and replaced 80% of the electric baseboard heaters (though admittedly the few that are left are monsters).
I'd love to see more models by manufacturers that have an established presence in typical US homes. When I went looking about two years ago for what options I had to replace my central furnace and AC, local installers really only had one or two options through the manufacturers they worked with.
Part of that is just lazy installers.
Keep in mind that 'buy it myself and pay somebody to install it' is still a perfectly viable option.
Absolutley, it's just added friction for the buyer. You still have to be pretty highly motivated to get a heat pump, which is a shame since they're the perfect answer in most cases.
One thing that these headline numbers don’t capture is how the efficiency changes with temperature. It seems like if ground source is going to do well anywhere, it would be in cold climates where air source is less efficient?
The opposite! Ground source is more efficient in cold weather than air source as it has no outdoor components. It relies exclusively on temperature deep underground. The temperature 400' down is remarkably stable over the year. And more than sufficient to facilitate the physics involved in the evaporation and condensing of the closed refrigerant.
Yeah, that’s what I was getting at.
Ha. I misread your comment, backwards. 👀
It's sort of a true story. The tax credits for my solar and geothermal installs made more than happy to sink the cash into the costs. But, paying for all my heating and all my cooling via solar generation is simply excellent.
For me, the calculation for a ground-source heat pump was two fold over an air-source heat pump:
I will say, if I finish my basement in the future, I can either cut into my ducting and add a third zone on my geothermal, or add an air-source heat pump on the walls in the basement. I very well might go for the air-source so that it's completely separate and I can simply disable all heating/cooling if I am not actively using the space. Though, to the frank, it will be more cost effective to simply add a little piddly third zone to the existing system, further driving the long term cost savings of ground source even higher.
Oh yes, I 100% agree. But basically I was looking at:
Spend $15,000 to install air-source minisplits.
Spend $45,000 to install a geothermal system.
It'd have taken over 40 years for the geothermal to be cost effective for that increased efficency, especially since the ground-source incentives were not a fraction of the air-source incentives.
Totally agree! I'm so happy to see the proliferation of ASHPs in the market and in people's homes. It's demonstrable progress for our society.
I'd love to see GSHPs continue to grown in prevalence, as they are more efficient. As that prevalence grows, costs will come down somewhat. But of course, realistically, ASHPs will win in the short- and medium-terms, for sure.
I'd just love to see new construction homes begin installing GSHPs as a default. If new homes had that, the economy of scale would really help the industry. That being said, new homes with all ASHPs would be perfectly fine in my book, too. We just need to stop building with propane and natural gas ASAP.
Interesting! I’m wondering how expensive your system was and how it would compare to an air-source heat pump. They seem pretty efficient too?
Realistically, I didn't think very seriously about ASHPs. I didn't want to wire up 4-6 of them throughout my house, and I didn't want the lower efficiency. My GSHP was $27k. installed prior to the 30% tax credit.
Random non expert speculation : it's still bad. In both case you use water to break rocks, which weakens the overall structure. I assume that this is this weakening that can cause earthquakes and sinkholes (I initially though it was replacing oil with water, but then remembered that water is more dense than oil).
Now maybe that you don't need to break as much rocks as in the oil extraction process. Then it's just a big, unelegant heat pump. I don't think heat pumps inherently poses problem (no mass exchange), though the initial drilling can (wasn't there a Tim Traveler episode about a German town that's sinking because the drilling hit an acquifer?).
I would be happy to be corrected with someone with actual expertise.
More fracking is not the answer!!
Exactly, however the article mentions new ways of setting these systems up.