Geothermal Energy

[Freegrass]

I couldn't find a dedicated thread for geothermal energy, and so I made one, because it looks like new techniques will be making it more viable. I'm curious to learn more about these new fracking techniques. What's the danger of them? Is it as bad as oil fracking? Or cleaner?

US aiming to ‘crack the code’ on deploying geothermal energy at scale
Recent $74m investment made alongside assessment that 10% of electricity could be generated by geothermal by 2050

https://www.theguardian.com/environment/2024/apr/02/geothermal-energy-electricity

A limitless supply of heat exists beneath our feet within the Earth’s crust, but harnessing it at scale has proved challenging. Now, a combination of new techniques, government support and the pressing need to secure continuous clean power in an era of climate crisis means that geothermal energy is finally having its moment in the US.

Until recently, geothermal has only been viable where the Earth’s inner heat simmers near the surface, such as at hot springs or geysers where hot water or steam can be easily drawn to drive turbines and generate electricity.

While this has allowed a limited number of places, like Iceland, to use geothermal as a main source of heating and electricity, it has only been a niche presence in the US, providing less than 1% of its electricity. But this could change dramatically, offering the promise of endless, 24/7 clean energy that can fill in the gaps of intermittent solar and wind generation in the electricity grid.

“Geothermal has been used for over 100 years, limited to certain geographic locations – but that is now changing,” said Amanda Kolker, the geothermal laboratory program manager at the National Renewable Energy Laboratory (NREL).

“As we penetrate the grid with renewables that are not available all the time, we need to find a base load, which is currently taken up by gas. There aren’t really many options for zero-emissions base load power, which is why geothermal is entering the picture.”

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.

“The US can lead the clean-energy future with continued innovation on next-generation technologies, from harnessing the power of the sun to the heat beneath our feet, and cracking the code to deploy them at scale,” said Jennifer Granholm, the US energy secretary, who added that she saw “enormous potential” in geothermal.

Expanding the geothermal footprint to the entire US will take time, as well as plenty of money – the department of energy estimates as much as $250bn will be needed for projects to become widespread across the country, providing a major source of clean power.

But advocates of geothermal say that such growth is within reach, because of a wave of geothermal technologies as well as government support. 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.

Ironically, enhanced geothermal uses similar fracking techniques currently used to extract oil and gas, which must be phased out if the world is to avoid climate disaster. In the geothermal version of fracking, fluid is injected deep underground, causing fractures to open up, with the liquid becoming hot as it circulates. The hot water is then pumped to the surface, where it can generate electricity for the grid.

This, and other new techniques that allow deeper and horizontal drilling, in some cases down to eight miles deep, allows geothermal energy to be drawn from hot rocks found anywhere underground, rather than select spots that have hot water near the surface. This vastly expands the potential of the technology.

“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.

At play for these companies is an inexhaustible energy supply. Just one type of next generation geothermal – called superhot rock energy, where deep drilling reaches temperatures 400C or hotter – is abundant enough to theoretically fulfil the world’s power requirements. In fact, just 1% of the world’s superhot rock potential could provide 63 terawatts of clean firm power, which would meet global electricity demand nearly eight times over.

“While this modelling is preliminary, our findings suggest an enormous opportunity to unlock vast amounts of clean energy beneath our feet,” said Terra Rogers, the director for superhot rock energy at Clean Air Task Force, which produced the modelling tool to measure the potential of this approach.

“Energy security backed by always available zero-carbon energy isn’t a far-off dream.”

[kassy]

There are many ways to do geothermal and many different scales on which it can be done.

If you pump water through a closed loop that limits the heat gain. If you do it on this grand scale as proposed one important question is how much water gets used. 

[Richard Rathbone]

Its not  exactly limitless. The geothermal heat flux across the entire planet is about 44 TW. Thats the same order of magnitude as the world's current energy use. However the vast majority of that is under the ocean.

Mean flux under land is 65 mW/m2
The USA is about 10M km2.

65 GW for the USA.
The USA currently uses about 3000 GW.

I think they are probably assuming that they can keep finding a new location to frack after they've cooled down the original fracked volume rather than what can be taken sustainably. Good luck finding a new US after the current one is completely fracked, which is what will happen if they try  to do geothermal at the sort of scale that article is talking  about.

Data from:
https://en.wikipedia.org/wiki/Geothermal_gradient
https://ourworldindata.org/energy-production-consumption

[morganism]

I was surprised how many fairly new books where in my local library on this, didn't know it was going forward so much. I like the idea of what they are doing in the Salton Sea tho, pairing geo with lithium and rare earth harvesting out of the brines seems like much saltier way to mine.

There was a team that got issued a permit to drill into a fairly recent volcano up in the Pac NW, never heard anything else on it.

There isn't a lot of research on fracking, other than plenty of technique, because the USA forbade any scientific research money going into it. Voted it in Congress.

[Sciguy]

Actually, geothermal is nearly limitless.  While the heat flux at the surface is pretty minimal that’s because the ground acts as an insulator.  Digging down, the temperatures get hotter.  And as the Wikipedia article linked above points out,

The heat of Earth is replenished by radioactive decay at a rate of 30 TW.[26] The global geothermal flow rates are more than twice the rate of human energy consumption from all primary sources. Global data on heat-flow density are collected and compiled by the International Heat Flow Commission (IHFC) of the IASPEI/IUGG.[27]

So by using the recent technology advances that allow for fracking oil and natural gas for geothermal energy, we would have a reliable source of 24/7 power that would supplement solar and wind.  100% renewable is possible with this combination of power generation sources.

[Richard Rathbone]

Actually, geothermal is nearly limitless.  While the heat flux at the surface is pretty minimal that’s because the ground acts as an insulator.  Digging down, the temperatures get hotter.  And as the Wikipedia article linked above points out,

The heat of Earth is replenished by radioactive decay at a rate of 30 TW.[26] The global geothermal flow rates are more than twice the rate of human energy consumption from all primary sources. Global data on heat-flow density are collected and compiled by the International Heat Flow Commission (IHFC) of the IASPEI/IUGG.[27]

So by using the recent technology advances that allow for fracking oil and natural gas for geothermal energy, we would have a reliable source of 24/7 power that would supplement solar and wind.  100% renewable is possible with this combination of power generation sources.

Getting hotter doesn't change the flux, just allows more of it to be used. Good luck extracting it  from under the Titanic. Thats where the vast majority of it is, under the deep ocean. Fracking the entire US and perfectly capturing the entire flux would be 2% of the current US energy usage not double it. Its never going to be anything but niche. It can be expanded, but its not making more than a tiny dent in the amount of solar thats needed.

Portraying it as limitless is a distraction tactic by Big Oil to draw attention away from the renewables that can actually replace them if they were pushed hard enough. Its about capturing the US research funding and causing it to be spent by them on something that doesn't threaten to strand their assets.

[gerontocrat]

Kenya has cracked it. I wonder if they got help from some Icelandic engineers?

But even there it is an addition to the mix of renewables and does not replace the urgent need to ramp up solar+wind and reshape the grid.

‘Our contribution to a cleaner world’: How Kenya found an extraordinary power source beneath its feet

The 1970s oil crisis helped pave the way for Kenya to utilise its vast geothermal resources beneath the Great Rift Valley

by Peter Muiruri

The Kenyan stretch of the Great Rift Valley is breathtaking. Vast plains between the two escarpments teem with wildlife, creating one of the world’s largest animal migrations – the Mara-Serengeti wildebeest migration. The alkaline lakes in the east African rift system are home to elegant and graceful flamingos, pink wonders that reels in visitors from around the world and are a vital cog in Kenya’s thriving tourism industry.

But it is what lies beneath the valley floor that has had a literally seismic impact on Kenya in recent years – vast geothermal resources that have made the country a world leader in clean energy.

Peketsa Mangi is the general manager in charge of geothermal development at KenGen, the country’s energy generating company. “We are lucky the African rift runs through Kenya,” he told me when I visited last week. “We just happened to be in the right place with several volcanic centres. Olkaria is one of these centres.”

Mangi and I are sitting in a gazebo overlooking a spa pool that uses brine, the byproduct of the geothermal development process. Visitors from all over Kenya come to enjoy the pool’s “healing” properties. With a power plant humming away nearby, my first visit to the heart of Kenya’s geothermal power generation turns out to be a lesson on what is going on below our feet.

According to the Geological Society, the Somalian and Nubian tectonic plates pulled away in opposite directions about 25m years ago, with the surface between the two fault lines sinking and bringing magmatic fluids closer to Earth’s surface and creating the famous rift, a vast valley that stretches 6,400km from Jordan to Mozambique. Under the valley, water percolates easily and comes into contact with hot rocks found 1-3km beneath the surface, creating a mix of superheated water and steam at 75% and 25% respectively, with temperatures averaging 300C (572F) and pressures of 1,000 PSI. These are, it turns out, the perfect conditions for generating geothermal energy.

“This is the steam we are tapping to run the turbines that generate electricity. It is rough down there, and that is where we go,” says Mangi. “A dangerous but necessary mission.”

Mangi has observed the behaviour of the valley for 27 years and knows exactly where to drill a well that will yield geothermal power. “Kenya has developed the capacity for precision geoscientific studies that help us to identify potential areas to drill. Exploration and drilling are cost-intensive endeavours and investors don’t want to go to a greenfield without confirmed viable resources,” he says.

Geothermal energy had its start in the small settlement of Larderello, Italy in 1904. The small plant provided 10kW of energy, which was used to power five lightbulbs. Since then, a number of countries have dug deep in order to exploit similar resources. The US, Indonesia, the Philippines, Turkey and New Zealand are the top five geothermal power producers in the world.

In Kenya, the search for underground energy began nearly 70 years ago, but stalled almost immediately. In 1956, the government drilled two wells specifically to harness geothermal power, at a depth of 950 metres and 1,200 metres respectively. “Temperatures averaged 235C (445F) but the wells failed to discharge due to poor permeability as the surrounding area was a bit solid,” says Mangi.

Then the oil crisis of the early 1970s happened and, once again, Kenya peered beneath the ground for an answer. Global organisations including United Nations Development Programme, The World Bank and Japan International Cooperation Agency stepped in to provide financial and technical support for further exploration. In 1971, a well was drilled and discharged. Everybody got excited again, Mangi says. Between 1981 and 1985, Kenya had an installed capacity of 45MW through the first three power plants in Olkaria.

“We don’t know where the country would be had the oil crisis not hastened this process,” Mangi says. “Geothermal is available 24/7 for 365 days. It is not affected by climate fluctuations since we are using water that has accumulated deep in the ground over the millenniums. The alternative would have been the installation of diesel generators that pollute the environment. This is our contribution to a cleaner world.”

Now, here at Olkaria, near the flower-growing town of Naivasha 56 miles (90km) from Nairobi, there are close to 300 geothermal wells providing steam that runs turbines in five geothermal power plants operated by KenGen.

The power plants and 15 wellheads have a combined capacity of 799MW. With additional geothermal power generated by independent power producers, Kenya’s total geothermal power capacity is 988.7MW, putting the country in sixth position globally (and first in Africa) in terms of geothermal power development.

As a result, Kenya sources up to 91% of its energy from renewables: 47% geothermal, 30% hydro, 12% wind and 2% solar. The country hopes to transition fully to renewables by 2030, with KenGen saying the country has the potential to increase its capacity to as much as 10,000MW of geothermal energy. That would more than match peak demand in Kenya, currently about 2,000MW. Peak time consumption in the UK is about 61,000MW.

Several wells sit within Hell’s Gate national park, the location that inspired the movie The Lion King. The park is patrolled by antelopes, giraffes, zebras and buffaloes, all roaming freely and oblivious to the immense energy trapped beneath their hooves and delivered to the power plants through a labyrinth of a high-pressure piping system averaging 74 miles (120km).

“Geothermal power is clean and poses no harm to the wildlife as the animals have adapted to this system,” says Gastone Odhiambo, a safety officer at the power plants. “These pipes are delivering steam to the turbines at 180C (356F) to produce 11 kilovolts of electricity that is then stepped up to 220 kilovolts to travel long distances. You need a sober mind since a single mishap can bring the country to a halt.”

Odhiambo’s childhood home in western Kenya did not have electricity. “I grew up in darkness,” he tells me at the plant’s control room full of switches, dials and strobe lights. “It is a heavy responsibility to help in generating clean energy that can go for ages. When you understand the process, how your tasks affect the day to day running of the economy, you remain humble.”

The Kenyan president, William Ruto, is now spearheading an African campaign to wean the continent off fossil fuels. In September last year, a declaration was signed, which called for reform of international finance and castigated the global north for the skewed global financial system that makes it difficult for Africa to harness its vast renewable energy resources.

“Despite Africa having an estimated 40% of the world’s renewable energy resources, only $60bn or 2% of $3tn renewable energy investments in the last decade have come to Africa,” read the declaration.

While Kenya and the rest of Africa await the financial reforms, it is a fulfilling assignment for the team that works at the geothermal plants in Olkaria, as Mangi sums it up: “A good day here is when the whole process works like clockwork. When all scientific studies and financial resources are poured into the ground, a well is drilled and it discharges, that is power to the country. You feel the investments are well used. And such good days are many.”

https://www.theguardian.com/environment/2024/jan/25/our-contribution-to-a-cleaner-world-how-kenya-found-an-extraordinary-power-source-beneath-its-feet#:~:text=The%20power%20plants%20and%2015,terms%20of%20geothermal%20power%20development.

[Freegrass]

Many thanks for all the responses! Great article Gero.

I've been doing my research on geothermal for the last 2 days, and one company stands out, Eavor Technologies. Their technology looks great. It's explained in the video below, and in a few more good videos on their YouTube channel.

They already started building a commercial system in Germany.

In total, Eavor is drilling four Eavor-Loops™ at the location. Together, they will generate approximately 64 MW of thermal power and 8.2 MW of electrical power, respectively, saving approximately 44,000 metric tons of CO2 equivalents per year. As early as summer 2024, one of the four Eavor-Loops™ will supply electrical energy for the first time. Completion of the entire plant is planned for 2027. Then the Eavor-Loop™ at Geretsried will be able to supply the entire region with district heating. Due to its advantages, the Eavor-Loop™ technology has the potential to become the gamechanger in energy supply for Germany and worldwide.

This is way better than fracking for hydrothermal. And we need this! For base load power, but mostly to heat our homes with district heating.

And the oil industry will be happy that they can keep drilling. But now for hydrothermal energy and natural hydrogen please.

[interstitial]

Actually, geothermal is nearly limitless.  While the heat flux at the surface is pretty minimal that’s because the ground acts as an insulator.  Digging down, the temperatures get hotter.  And as the Wikipedia article linked above points out,

The heat of Earth is replenished by radioactive decay at a rate of 30 TW.[26] The global geothermal flow rates are more than twice the rate of human energy consumption from all primary sources. Global data on heat-flow density are collected and compiled by the International Heat Flow Commission (IHFC) of the IASPEI/IUGG.[27]

So by using the recent technology advances that allow for fracking oil and natural gas for geothermal energy, we would have a reliable source of 24/7 power that would supplement solar and wind.  100% renewable is possible with this combination of power generation sources.

Getting hotter doesn't change the flux, just allows more of it to be used. Good luck extracting it  from under the Titanic. Thats where the vast majority of it is, under the deep ocean. Fracking the entire US and perfectly capturing the entire flux would be 2% of the current US energy usage not double it. Its never going to be anything but niche. It can be expanded, but its not making more than a tiny dent in the amount of solar thats needed.

Portraying it as limitless is a distraction tactic by Big Oil to draw attention away from the renewables that can actually replace them if they were pushed hard enough. Its about capturing the US research funding and causing it to be spent by them on something that doesn't threaten to strand their assets.

https://atb.nrel.gov/electricity/2022/geothermalThe total mean potential estimated by the U.S. Geological Survey (USGS) in 2008 is 39,090 MW: 9,057 MW identified and 30,033 MW undiscovered (USGS, 2008).
So 39 GW of nearly 100% capacity factor of power making it equivalent to about 65 GW of gas or 91 GW of coal or 117 GW of wind or 162 GW of solar. It is better than wind or solar because it is nearly always on at full power. 39 GW of always on geothermal is about 5.5% of US power. But that number is technology limited for just hydrothermal and NF-EGS(Near hydrothermal Field Enhanced Geothermal Systems). Deep-EGS (3-6km) can add another +100 GW or another 14% or so total that is about 20% of US energy from geothermal. The deeper you drill the more sites can be exploited so that could potentially go much higher. All EGS sights are located in "natural heat zones" so there are other locations possible with even deeper drilling. No drilling under the ocean required though certainly technically possible.


The point is the 39 GW or 5.5% of US power is not even close to the thermal flux you are misinformed or mistaken.


I might also add that oil companies are not pursuing it former oil company employees are.

[Richard Rathbone]

The point is the 39 GW or 5.5% of US power is not even close to the thermal flux you are misinformed or mistaken.

Thats about half my estimate of the thermal flux. i.e. they are assuming the entire US is fracked to get those numbers and probably to a pretty extreme depth too, because thermal power plants  have to be extremely hot to have efficiencies around 50%. Eavor could get a bit more than 11% if they were heating rivers with waste heat rather than houses but thermal power plants with efficiencies that high have input temperatures around 1000C.

Throw a lot of money at it, and I expect they can turn 2 into 5 or maybe even 10GW, but its  niche, not limitless and its actual limits are a small fraction of US energy demand.

ex-oil personnel doing green research reminds me of Beyond Petroleum. BP still uses the Beyond Petroleum logo,  but they spun out their solar R&D into a company contracted to them when they sacked their woke CEO and doubled down on Russian gas after deciding that Kyoto was going nowhere. Oil companies are full of people that can do these estimates,  and they know geothermal  is going almost nowhere too.

[interstitial]

The point is the 39 GW or 5.5% of US power is not even close to the thermal flux you are misinformed or mistaken.

Thats about half my estimate of the thermal flux. i.e. they are assuming the entire US is fracked to get those numbers and probably to a pretty extreme depth too, because thermal power plants  have to be extremely hot to have efficiencies around 50%. Eavor could get a bit more than 11% if they were heating rivers with waste heat rather than houses but thermal power plants with efficiencies that high have input temperatures around 1000C.

Throw a lot of money at it, and I expect they can turn 2 into 5 or maybe even 10GW, but its  niche, not limitless and its actual limits are a small fraction of US energy demand.

ex-oil personnel doing green research reminds me of Beyond Petroleum. BP still uses the Beyond Petroleum logo,  but they spun out their solar R&D into a company contracted to them when they sacked their woke CEO and doubled down on Russian gas after deciding that Kyoto was going nowhere. Oil companies are full of people that can do these estimates,  and they know geothermal  is going almost nowhere too.

They are not assuming the entire US is fracked or at extreme depths to get 39 GW. That 39 GW is in locations were they have to drill less than 3 km to get usable heat which is certainly not everywhere. If they drill deeper more locations become usable adding depths of 3-6 km adds another 100+ GW. Your flux estimates are wrong.


I include a reference to the National Energy Renewable Laboratory website which is backed by actual citations of research you just make a claim without reference to anything.

https://atb.nrel.gov/electricity/2023/geothermal

[Freegrass]

It took me a while, but I finally found this video again about a new drilling technique that would make drilling much cheaper, with a possibility to go much deeper too.

Together with the Eavor Loop technology, this could revolutionize geothermal energy and give us cheap, reliable, base load power, and make us less dependable on chemical batteries.

I think it's also great for seasonal storage. Use it a lot in winter, and let the rocks heat up again in summer.

Drill, baby, drill!

[interstitial]

That video was interesting Freegrass thank you. That video is more than a year old. I checked the Quaise Energy website and they still show the hybrid drilling system drilling this year and completing a 100 mw plant by 2026. If everything goes smoothly it should pick up from there but even if it does it will not be a major source of energy before mid to late 2030's. Geothermal is 24/365 power you could shut it down for low demand times but unless you have too much energy that just increases the wear and tear on the equipment.


https://www.quaise.energy


An article about a former oil and gas VP who now works at Quaise Energy
https://www.texastribune.org/2024/03/26/texas-geothermal-energy-oil-and-gas/


“Recovery of just 2% of the thermal energy stored in hot rock 3 to 10 km [2 to 12 miles] below the continental U.S. is equivalent to 2,000 times the primary U.S. energy consumption” annually, he and Callahan write in their paper.
https://www.eurekalert.org/news-releases/1039007


This provides updates including drilling this autumn in Texas.
https://spectrum.ieee.org/geothermal-energy-gyrotron-quaise


According to the Clean Air Task Force, merely 1% of this “superhot rock” geothermal potential could meet global electricity demand multiple times over.
https://www.quaise.energy/news/why-fossil-fuels-are-so-addictive

[kiwichick16]

@ interstitial   .....from the last link in your last post ......from the Energy.gov website .....they put energy capacity of geothermal at 71 %  .....compared to coal at 49 % and solar PV at 24 %

[interstitial]

@ interstitial   .....from the last link in your last post ......from the Energy.gov website .....they put energy capacity of geothermal at 71 %  .....compared to coal at 49 % and solar PV at 24 %

I am looking for energy.gov website reference and do not see it. Energy capacity is what? Capacity factor? Something else?

[kiwichick16]

https://www.energy.gov/ne/articles/what-generation-capacity  .....from the Quaise article  ....why fossil fuels are so addictive ..... link on the word ..rank....

[interstitial]

@ interstitial   .....from the last link in your last post ......from the Energy.gov website .....they put energy capacity of geothermal at 71 %  .....compared to coal at 49 % and solar PV at 24 %

So those are indeed capacity factors. Geothermal can run nearly 24/365 but does not because it is not economic to do so. Coal can run more often too in the 70's was how often they used to run in the US but no longer. Solar was at 25% but I think curtailment has caused that to decline. The following is from the same website in a different location.
Geothermal energy is available 24 hours a day, 365 days a year, regardless of weather. Geothermal power plants have a high-capacity factor—typically 90% or higher—meaning that they can operate at maximum capacity nearly all the time.
[/size]From the "What are the benifits of using geothermal energy?"[/color]
[/size]https://www.energy.gov/eere/geothermal/geothermal-faqs[/color]

[Freegrass]

That video was interesting Freegrass thank you. That video is more than a year old. I checked the Quaise Energy website and they still show the hybrid drilling system drilling this year and completing a 100 mw plant by 2026. If everything goes smoothly it should pick up from there but even if it does it will not be a major source of energy before mid to late 2030's. Geothermal is 24/365 power you could shut it down for low demand times but unless you have too much energy that just increases the wear and tear on the equipment.

https://www.quaise.energy


An article about a former oil and gas VP who now works at Quaise Energy
https://www.texastribune.org/2024/03/26/texas-geothermal-energy-oil-and-gas/


“Recovery of just 2% of the thermal energy stored in hot rock 3 to 10 km [2 to 12 miles] below the continental U.S. is equivalent to 2,000 times the primary U.S. energy consumption” annually, he and Callahan write in their paper.
https://www.eurekalert.org/news-releases/1039007


This provides updates including drilling this autumn in Texas.
https://spectrum.ieee.org/geothermal-energy-gyrotron-quaise


According to the Clean Air Task Force, merely 1% of this “superhot rock” geothermal potential could meet global electricity demand multiple times over.
https://www.quaise.energy/news/why-fossil-fuels-are-so-addictive

Nice research and excellent article about geothermal in Texas Interstitial! Incredible how many renewables Texas has right now. More than California I picked up somewhere.

Oil country is going green, and I really do hope they are as excited about geothermal and natural hydrogen as I am. It's right in their alley. They have all the drilling knowledge.

Here's a pretty good video from the Fully Charged Show from last year about geothermal in the UK. District heating may be the way forward for Britain and other countries. It could definitely move decarbonization faster forward than insulation and heat pumps IMHO. Curious what others here have to say about this.

[Freegrass]

Interesting idea, but this only works with enhanced geothermal (fracking).

Geothermal May Beat Batteries for Energy Storage
Enhanced geothermal systems are well suited to store excess renewable power as heat.

https://spectrum.ieee.org/geothermal-energy

Geothermal systems carry warmth from Earth’s interior up to the surface for heating or electricity. But geothermal power plants are expensive to build, and will get even less economically viable as wind and solar power get cheaper and more plentiful. However, even as wind and solar grow, so does the need to store electricity from those temperamental sources.

A new proposal could solve those issues and bolster all three renewable technologies. The idea is simple—use advanced geothermal reservoirs to store excess wind and solar power in the form of hot water or steam, and bring up that heat when wind and solar aren’t available, to turn turbines for electricity.

“It would allow next-generation geothermal plants to break from the traditional baseload operating paradigm and earn much greater value as suppliers of wind and solar,” says Wilson Ricks, a graduate student in mechanical and aerospace engineering at Princeton University.

Ricks, his Ph.D. advisor Jesse Jenkins, and Jack Norbeck, cofounder and chief technology officer of Houston-based advanced geothermal developer Fervo Energy, ran extensive simulations of such geothermal reservoir energy storage to see if the technical components of the system as well as the economics actually work out. They found that the systems could indeed store electricity over a range of time scales, from a few hours up to many days, as efficiently as lithium-ion batteries. Plus, says Ricks, “the storage capacity effectively comes free of charge with construction of a geothermal reservoir.”

Their results apply only to enhanced geothermal plants, like the ones Fervo and other companies such as Cambridge, Mass.–based Quaise Energy and Seattle-based AltaRock Energy are developing.

Conventional geothermal systems drill wells into naturally occurring hydrothermal reservoirs. But these pockets of hot water deep underground do not exist everywhere. In the United States, for instance, they are mostly located in the west.

Enhanced geothermal systems (EGS) get around this geographical limitation by creating artificial reservoirs. Developers create fractures in hot, dry rock formations by drilling into or melting the rock, and then injecting water into the fissures. Production wells bring the heated water up for producing electricity. “For scales necessary to contribute to national or global electricity decarbonization, we need to be able to extract geothermal heat outside of conventional formations,” Ricks says.

Fervo Energy raised US $138 million in venture capital funding in August to advance its technology. The company uses innovations from the oil and gas industry, such as horizontal drilling and distributed fiber-optic sensing, to create underground reservoirs. The company plans to use the new funds to complete two pilot projects, including one with Google in Nevada.

Once these EGS systems are in place, they would be ideal for storing energy as well as producing electricity. Excess wind or solar energy could be used to inject water into the artificial reservoirs, where it would accumulate and build up pressure. The production wells could then be opened up when electricity is needed.

“EGS reservoirs are created in rock formations that are naturally impermeable; everything outside the artificial reservoir is sealed off,” says Ricks. “It’s very similar to a hydropower reservoir, where you choose when to have water go through the dam and generate electricity.”

Depending on the geology and traits of the rocks, Ricks and his colleagues’ simulations found that the systems could store energy with up to 90 percent efficiency over one cycle. That’s comparable with lithium-ion and pumped hydro storage, he says. The cost, meanwhile, would be minimal compared to other energy storage technologies. It would require larger facilities on the surface, but the storage space would be effectively free, since the EGS reservoirs are being built for electricity anyway.

In January, the team received $4.5 million in funding from the Advanced Research Projects Agency–Energy (ARPA-E) to demonstrate a full-scale test of geothermal reservoir energy storage in the field. The detailed findings of their modeling study appear in a paper published recently in the journal Applied Energy.

This article appears in the December 2022 print issue as “Hot Rocks Best Batteries for Energy Storage.”


The value of in-reservoir energy storage for flexible dispatch of geothermal power
https://www.sciencedirect.com/science/article/abs/pii/S0306261922002537#!

[kiwichick16]

not sure if this has been posted ....

https://www.newsweek.com/superhot-rock-geothermal-unlock-vast-amounts-clean-energy-1882436

.....1 % of superhot rocks could generate 63 terrawatts   .....more than 7 times global demand in 2021

they could be overly optimistic of course ............

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not sure if this has been posted ....

https://www.newsweek.com/superhot-rock-geothermal-unlock-vast-amounts-clean-energy-1882436

.....1 % of superhot rocks could generate 63 terrawatts   .....more than 7 times global demand in 2021

they could be overly optimistic of course ............

I am guessing that is based on the total global thermal flux without consideration to location, depth, accessibility or extraction efficiencies. It seems less likely but it may even be the heat in all the rock in the earth though I think that number would be much larger.

[kassy]

Well they say there are many locations.

If we do this you can then start putting much smaller operations near areas where you need it.
The big limiting factor is probably water use

[Freegrass]

Well they say there are many locations.

If we do this you can then start putting much smaller operations near areas where you need it.
The big limiting factor is probably water use

I don't think water use will be a very big problem in most cases, because water comes out of the well in enhanced systems, after which it is constantly circulated back into the system.

In a closed loop system - like the one from Eaver - you will need to fill up the well, and then again keep circulation the same water.

Not sure how much loss of water there would be from the release of steam during production and other things. Something I'll take a look at later.


I was just looking at this great video on Enhanced Geothermal Systems (EGS), and she convinced me that geothermal fracking could be done much more safely than oil fracking. Mostly due to the fact that they don't use chemicals in EGS. Just pure water.

And the earthquakes can be avoided, they say, because of years of experience in the oil industry.

What I like about EGS is that these systems could be used for energy storage as well. That would double their functionality for almost the same price. And that's pretty good if you ask me.

So do we like EGS, or not? I'm warming up to it thanks to this video. Curious how you all feel about it.

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Where heat is close to the surface tends to be on or near crust boundaries but where it is deeper is away from crust boundaries and the geology is more stable so earthquakes are less likely.


In a fracked well they drill a hole then pump a ton of water sand and other chemicals to open and keep open the cracks. Then for the geothermal well they pump clean water into it. The water picks up all sorts of minerals and depending on the minerals they need to be removed before the water can be used again.


In a closed loop much more drilling has to be done to get the same heat transfer but no chemicals or sand are pumped down. When the well is drilled by the millimeter wave laser the sides are sealed and the water does not pick up minerals or at least very little. This also has the advantage that the water does not have to be pumped down the hole except initially to start it. The water expanding into steam drives the circulation in closed loop systems once started. The energy used by circulating pumps is a huge energy drain on the non closed loop systems.


Fracked wells will have higher operational costs due to the pumping and the need to clean the water. Fracked wells will probably be much cheaper to build because there is less distance to be  drilled. This is just a guess though because the millimeter laser is expected to be much cheaper per meter. The costs of the deep closed well with millimeter laser or so called fusion tech are yet to be determined because the first one will be drilled this fall. 

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EGS whether fracked or closed loop are both good but closed loop is better if the cost is the same.


Water use can be high for tower or pond cooling or lower for closed loop or dry cooling. In general the cheaper to build the more expensive to run.