Deep Geothermal Energy Production Progress in Utah

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Mark Z. Jacobson has proposed converting the entire energy production of the world to clean energy. He regards “Wind, Water, and Solar” (WWS) as the only methods that can do this practically, quickly, and economically. Of those, hydroelectric power is the only relatively continuous source, but it cannot be easily increased in most parts of the world. In a given spot, wind doesn’t blow all the time, but in a large country like the US, the wind is always blowing in some regions. Therefore, with sufficient long-distance, high-voltage DC energy transmission, wind energy could become a constant energy source. Unfortunately, it takes a long time to build long-distance transmission lines.

Fortunately, solar energy matches the midday air conditioning peak load in warm climates. However, it doesn’t match the early evening peak load, especially in winter. It also doesn’t supply the continuous power required for data centers, nighttime heating, and lighting. Energy storage will solve this problem eventually. Battery storage will reach 46 gigawatts in the US by the end of 2025, but it is still a small fraction of what is needed. Other methods of storage, particularly pumped hydro, take a long time to build.

So, why has Jacobson ruled out geothermal as a source to fill in the gaps in solar and wind energy production?

It appears he has not considered geothermal because with the present generation of geothermal power plants, it is only possible in the relatively few regions of the world with hot enough rocks and water close to the surface.

The breakdown of conventional geothermal in Utah at present is as follows:

• 34 MW — Blundell Geothermal Facility near the site of the FORGE experiment (Beaver County)
• 25 MW — Cove Fort Geothermal Power Plant, to be expanded to ~100 megawatts (Beaver County)
• 14 MW — Thermal No. 1 Geothermal Project (Beaver County)
• 73 megawatts total (148 MW planned)

The following two photos show the Cove Fort geothermal plant.

The Utah Green Energy total is 3899 megawatts, so with the Utah geothermal total at 73 megawatts, present geothermal energy production is less than 2% of the Utah total.

The largest geothermal power plant in the world is the Geysers in California. It is comprised of 15 separate plants with a total output of 1.2 gigawatts. One of them is shown in the figure below.

The US conventional geothermal power production total is only 3.7 gigawatts (GW). US geothermal power plants are only in the western states of California, Nevada, New Mexico, Oregon, Hawaii, Idaho, and Utah. US total power generation capacity is 1189 gigawatts, so geothermal is only 0.3% of the US total at the moment.

But … what about using deeper sources of thermal energy available in most locations around the world that may possibly be accessed in the future? There have even been discussions of using abandoned oil production wells. This technology would be particularly attractive in the US where oil company prospecting and drilling technology could be employed, which wouldn’t be subject to the terrible anti–clean energy biases of the Trump administration. Bottom line: this is attractive technology that could be employed nearly anywhere in the world.

Ironically, only 50 miles southwest of the Cove Fort geothermal plant, the University of Utah with support of the US Department of Energy has been conducting the FORGE (Frontier Observatory for Research in Geothermal Energy) experiment near Milford, Utah. This is near the same site I visited a few weeks ago where a large solar PV farm, a large wind farm, and numerous hog farms are co-located, as shown in the photo below.

FORGE has drilled injection and production holes side by side 300 feet apart as shown in the diagram in the lead figure. This EGS experiment used the two wells drilled through sedimentary rock into granite to a vertical depth of about 8000 feet to test the concept of deep geothermal energy extraction.

Here’s more on the FORGE project (verb tense changed): “Like the injection well, the upper part of the well was drilled vertically through approximately 4,550 feet of sediments at which point it penetrated into hard crystalline granite. At about 5,600 feet, the well was gradually steered at a 5-degree angle for each 100 feet until it reached an inclination of 65 degrees from its vertical point. The total length of the well is approximately 10,700 feet with the ‘toe’ — or the end of the well — reaching a vertical depth of 8,265 feet. The temperature at this depth is 440 degrees F.”

The photo below shows the FORGE drilling rig near Milford, Utah.

Water is forced into the injection well, fracturing the rock between the injection well and the production well 300 ft away. Then the cold water forced into the injection well is heated as it traverses the hot fractured rock and is withdrawn at the surface at temperatures as high as 139°C from the production well. This is easily hot enough to produce steam to drive turbines.

Only about a mile away, the same technology will be put to use to produce a significant amount of power.

According to the Salt Lake Tribune: “Fervo Energy has announced new financing and technical advances that put the Houston-based company on track to open the world’s largest enhanced geothermal power plant in Beaver County in two years.

“The Cape Station plant is scheduled to start producing 90 megawatts of continuous power in 2026 (next year), but the plan is to expand to 400 megawatts by 2028, which would put it among the top 10 Utah electricity sources. It would be smaller than the state’s coal plants but larger than any hydroelectric plant in the state, including the Flaming Gorge Dam.

“Were it not for transmission limitations, Cape Station could supply even more power,” said Chelsea Anderson, strategic communications specialist for Fervo. “We believe that Cape has at least 2 gigawatts of geothermal potential.”

My comment: the largest coal power plant in Utah (1.6 gigawatts) at Delta is 60 miles north of Milford and it sends its power to Los Angeles via lines passing near Milford. The capacity of the Delta plant will be reduced in half this year, so those lines should have excess capacity.

“It will also be ‘dispatchable’ power, which the Utah legislature has made a priority. By varying the amount of water pumped through the system, the plant can produce power on demand or shut down when intermittent sources like solar and wind are producing.”

Earlier this year, Fervo said it had drilled its latest Cape Station well into the solid granite in 21 days, which is 70% faster than the first test wells it drilled in 2022. The faster drill times mean lower costs. For the first 90-megawatt phase, the company expects to drill 20 to 24 wells more than two miles long.

“We drill roughly 8,000 feet deep and 5,000 feet horizontally,” Anderson noted, who added that the company will test hot water production in the next few months.

You still have the relatively high cost of drilling the wells, and you need a water supply. Although, the water can be reused repeatably. Furthermore, you have the possibility of causing earthquakes from the fracking.

Geothermal energy seems like a great additional source of clean energy, despite not being perfect. Unfortunately, a global CleanTechnica expert on the subject doesn’t see significant world energy production by deep geothermal in the near future.