geothermal energy

3 Articles

Utah’s FORGE: A Research Laboratory For Enhanced Geothermal Systems

March 14, 2025 by 6 Comments

Geothermal heat is a tantalizing source of energy that’s quite literally right below our feet. At the same time geothermal energy is hard to develop as the Earth’s crust is too thick in most places, limiting this to areas where magma is close enough to the surface and the underground rock permeable enough for water. The Utah FORGE facility is a field site were researchers are developing and testing ways to increase the scope of geothermal energy.

An Enhanced Geothermal System (EGS) is designed to be capable of using geothermal energy where this is normally not feasible through a technique that’s reminiscent of the hydraulic fracturing (‘fracking’) used by the oil and gas industry, but rather than creating more fractures, it instead uses hydro-shearing to prop open existing fractures and thus create the through-flow of water needed to extract geothermal energy.

So far FORGE has reported the successful creation of a geothermal reservoir where before there was none. This facility is located in the Milford valley in southwest Utah, which has some hydrothermal activity at the nearby Roosevelt Hot Springs, but through EGS other parts of this valley and similar areas could conceivably be used for generating electricity and for community heating as well. In a 2024 study by University of Utah scientists, it is described how the Milford valley’s volcanic past has left a large body of magma below a thick barrier of granitic rock that could provide access to geothermal resources with EGS to create the requisite fluid permeability.

FORGE is not the only facility working on EGS, but many other sites around the world having ceased activities after issues ranging from induced seismicity, susceptibility to earthquakes and budget shortages. Much like fracking, EGS is likely to cause earthquakes. Whether EGS can be made economically feasible still remains to be seen.

Image Credit: Eric Larson, Flash Point SLC

Using Old Coal Mines As Cheap Sources Of Geothermal Heat

April 11, 2023 by 33 Comments

For as much old coal mines are a blight upon the face of the Earth, they may have at least one potential positive side-effect. Where the coal mine consists out of tunnels that were drilled deep into the soil, these tend to get flooded by groundwater after the pumps that keep them dry are turned off. Depending on the surrounding rock, this water tends to get not only contaminated, but also warmed up. As the BBC explains in a recent video as a follow-up to a 2021 article, when the water is pumped up for decontamination, it can be run through a heat exchanger in order to provide heat for homes and businesses. Continue reading “Using Old Coal Mines As Cheap Sources Of Geothermal Heat” →

AGES Of Renewable Energy Storage

March 3, 2023 by 26 Comments

As society transitions toward renewable energy sources, energy storage inevitably comes to mind. Researchers at the University of Illinois at Urbana-Champaign have found one way to store renewable energy that re-purposes existing fossil fuel infrastructure.

While geothermal electricity generation shows a lot of promise, it’s currently limited to a select few areas where hot rock is close to the Earth’s surface. Advanced Geothermal Energy Storage (AGES) stores energy underground as heat and recovers it later, even in places without high subsurface temperatures. For this study, the researchers located an old oil well and instrumented it with “flow meters, fiber optic
distributed temperature sensing (DTS) cable, surface pressure and temperature gauges, and downhole pressure and temperature gauges to monitor the thermal and hydraulic changes during the injection test.”

This field study found that AGES system efficiency could be as high as 82% and yield an “economically viable” levelized cost of electricity (LCOE) of $0.138/kWh. Using existing deep hole infrastructure speeds up site selection and deployment of AGES when compared to developing on an undisturbed location, making this a very interesting way to deploy grid-scale storage rapidly.

We’ve covered reusing fossil fuel infrastructure before as well as challenges and unusual solutions to the energy transition if you’re looking for more about what might be on a future smart grid.