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The word ‘geothermal’ is overloaded these days and can mean one of two things: 1. Extracting heat energy from magma within the earth via steam turbines. This i

The word ‘geothermal’ is overloaded these days and can mean one of two things: 1. Extracting heat energy from magma within the earth via steam turbines. This is what is mentioned in the article. 2. Using the ground as a sort of infinite thermodynamic reservoir via a heat pump working as the same principle as a refrigerator.

Retric 2y ago
There isn’t such a clear line between those two as going slightly deeper for slightly warmer rock makes a big difference when you mostly want heat from that heat pump. ~1c per 40m may not sound like much, but it quickly adds up over 50 years.
- pfdietz 2y ago
  There was a story in the NY Times six months ago about colleges in the US going with geothermal. Many are putting in shallow geothermal to be used with heat pumps (depth ~900 feet), but Cornell has also been looking at true geothermal with an exploratory well to nearly 10,000 feet (bottom temperature was 82 C). https://www.nytimes.com/2024/01/23/climate/geoexchange-climate-colleges-heat.html https://www.nytimes.com/2024/01/23/climate/geoexchange-clima... (may be paywalled)
cwal37 2y ago
This is more people just casually conflating two separate terms: geothermal and ground-source. Pretty frustrating since it is right there in the name of each, ground-source heat pumps are near-surface and basically leveraging the annual average air temperature while geothermal resources are leveraging higher temperatures much deeper in the earth.
- QuercusMax 2y ago
  My dad had a "geothermal" heat pump installed back in the late 90s; that was the term that was commonly used at the time. The US Department of Energy uses that term even today: https://www.energy.gov/energysaver/geothermal-heat-pumps https://www.energy.gov/energysaver/geothermal-heat-pumps Not sure where you're hearing the term "ground-source heat pump" in common usage, but it certainly has not filtered out into common parlance.
  - samatman 2y ago
    It's also correct. They exploit heat (thermos) from the Earth (geos). A geothermal power plant and a geothermal heat pump differ in many particulars, but not in the meaning of the adjective they share in common.
  - hardlianotion 2y ago
    Ground source heat pump is often used in UK.
hnburnsy 2y ago
Does this help? "The system comprises an injection and production well pair drilled within a high-temperature, hard-rock geothermal formation. According to Fervo, the lateral sections of the wells were drilled leveraging technology innovations from the unconventional oil and gas industry with a 9 7/8-inch hole size, completed with 7-inch casing, and extended about 3,250 feet horizontally. They reach a maximum measured temperature of 376F (191C)." https://www.powermag.com/innovative-enhanced-geothermal-system-begins-operations-in-nevada/ https://www.powermag.com/innovative-enhanced-geothermal-syst...
WarOnPrivacy 2y ago
> The word ‘geothermal’ is overloaded these days and can mean one of two things: It's an umbrella term; it covers methods that leverage temperature differences between the ground and the air to exchange energy. In FL, 64° aquifer water is used for cooling structures over 15k²ft. I worked on control systems for those.
aaron695 2y ago
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Retric 2y ago

There isn’t such a clear line between those two as going slightly deeper for slightly warmer rock makes a big difference when you mostly want heat from that heat pump. ~1c per 40m may not sound like much, but it quickly adds up over 50 years.

pfdietz 2y ago
There was a story in the NY Times six months ago about colleges in the US going with geothermal. Many are putting in shallow geothermal to be used with heat pumps (depth ~900 feet), but Cornell has also been looking at true geothermal with an exploratory well to nearly 10,000 feet (bottom temperature was 82 C). https://www.nytimes.com/2024/01/23/climate/geoexchange-climate-colleges-heat.html https://www.nytimes.com/2024/01/23/climate/geoexchange-clima... (may be paywalled)

cwal37 2y ago

This is more people just casually conflating two separate terms: geothermal and ground-source. Pretty frustrating since it is right there in the name of each, ground-source heat pumps are near-surface and basically leveraging the annual average air temperature while geothermal resources are leveraging higher temperatures much deeper in the earth.

QuercusMax 2y ago
My dad had a "geothermal" heat pump installed back in the late 90s; that was the term that was commonly used at the time. The US Department of Energy uses that term even today: https://www.energy.gov/energysaver/geothermal-heat-pumps https://www.energy.gov/energysaver/geothermal-heat-pumps Not sure where you're hearing the term "ground-source heat pump" in common usage, but it certainly has not filtered out into common parlance.
- samatman 2y ago
  It's also correct. They exploit heat (thermos) from the Earth (geos). A geothermal power plant and a geothermal heat pump differ in many particulars, but not in the meaning of the adjective they share in common.
- hardlianotion 2y ago
  Ground source heat pump is often used in UK.

hnburnsy 2y ago

Does this help? "The system comprises an injection and production well pair drilled within a high-temperature, hard-rock geothermal formation. According to Fervo, the lateral sections of the wells were drilled leveraging technology innovations from the unconventional oil and gas industry with a 9 7/8-inch hole size, completed with 7-inch casing, and extended about 3,250 feet horizontally. They reach a maximum measured temperature of 376F (191C)." https://www.powermag.com/innovative-enhanced-geothermal-system-begins-operations-in-nevada/ https://www.powermag.com/innovative-enhanced-geothermal-syst...

WarOnPrivacy 2y ago

> The word ‘geothermal’ is overloaded these days and can mean one of two things: It's an umbrella term; it covers methods that leverage temperature differences between the ground and the air to exchange energy. In FL, 64° aquifer water is used for cooling structures over 15k²ft. I worked on control systems for those.

aaron695 2y ago

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