Drilling nearly three miles into the ground at temperatures well over two times the boiling point of water, geothermal company Fervo Energy said it has set several records with its deepest and hottest well to date.

The Houston-based company on June 10 said its Sugarloaf appraisal well, part of Fervo’s Cape Station geothermal development in Utah, reached a true vertical depth of 15,765 ft with projections to reach a bottomhole temperature of 520 F. The well was drilled in 16 days, nearly 80% faster than the U.S. Department of Energy’s baseline for ultradeep geothermal wells, the company said.

Geothermal energy involves drilling wells into hot reservoirs to capture heat that can be converted into electricity, providing baseload power. Enhanced geothermal systems (EGS), such as those used by Fervo, lean on proven techniques and technologies used in oil and gas. The energy source is seen as a route to lower carbon emissions while meeting rising energy demand, if developers are able to bring down costs and successfully scale.

“Back in July 2020, we performed our first EGS field trials at reservoir temperatures of around 300 F,” said Jack Norbeck, CTO and co-founder of Fervo Energy. “In just a few years, we’ve developed innovations that enable our technology to operate reliably at temperatures exceeding 500 F. These drilling results demonstrate that Fervo is operating in the optimal geothermal conditions for large-scale commercial deployment.”

The ability to drill deeper and into hotter temperatures expands the commercial viability window for enhanced geothermal systems, according to Fervo.

Other drilling performance records set by Sugarloaf include a maximum bit run length of 3,290 ft, a maximum average rate of penetration of 95 ft/hr, and an instantaneous ROP of over 300 ft/hr at depths greater than 15,000 ft, Fervo said.

Sugarloaf is part of the 500-megawatt greenfield Cape Station Fervo is developing in southwest Utah. However, the site may be capable of producing much more electricity.

A report by DeGolyer & MacNaughton stated Fervo’s proprietary EGS design could unlock thermal recovery factors in the range of 50% to 60% and support over 5 gigawatts of development at depths of up to 13,000 ft, Fervo said June 10.

“The new Sugarloaf drilling results are expected to increase Cape’s resource potential even further,” Fervo said.

Geothermal energy produced from the site has been contracted to customers that include Shell Energy and Southern California Edison. The project is being developed in phases: Phase 1 is expected to be operational by 2026 with additional phases by 2028.

Founded about seven years ago, Fervo is a portfolio company of Bill Gates-backed Breakthrough Energy. The company is also backed by Devon Energy and SLB. Fervo brought its first project onto the grid in 2023, providing electricity in Nevada, where partner Google’s data centers are powered.

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