Fervo Energy has published early drilling results from its Cape Station geothermal project that it says exceed the Department of Energy’s (DOE) expectations for enhanced geothermal systems (EGS).

Fervo began its drilling campaign at Cape Station, its 400 MW project in southwest Utah, in June 2023 and over the last six months has drilled one vertical and six horizontal wells there, while it says it reduced drilling times from well to well as learnings accelerated.

Fervo says it has reduced drilling times and costs in horizontal, high-temperature, deep granite drilling. Though Cape wells are hotter and over 2,100 feet deeper than Project Red wells, Fervo says it drilled its fastest Cape well in just 21 days, a 70% reduction in drilling time from Fervo’s first horizontal well drilled at Project Red in 2022. Fervo says the increase in efficiency has resulted in cost reductions, with drilling costs across the first four horizontal wells at Cape falling from $9.4 million to $4.8 million per well.

Fervo Energy co-founder and CEO Tim Latimer joined the Texas Power Podcast with Doug Lewin to discuss a hoped-for resurgence in the geothermal energy industry. Subscribe wherever you get your podcasts.

“Since its inception, Fervo has looked to bring a manufacturing mentality to enhanced geothermal development, building a highly repeatable drilling process that allows for continuous improvement and, as a result, lower costs,” said Tim Latimer, Fervo Energy CEO and Co-Founder. “In just six months, we have proven that our technology solutions have led to a dramatic acceleration in forecasted drilling performance.”

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Fervo says it achieved its results by increasing both the rate of penetration (ROP) and the life of drill bits. On the fourth horizontal well drilled at Cape, Fervo sustained an average ROP of 70 feet/hour, which it says already outpaced NREL’s 2035 projections for moderate technology improvement.

Fervo used polycrystalline diamond compact (PDC) drill bits typically deployed in shale basins to cut through hard, abrasive granite, while mud coolers counteracted high subsurface temperatures that have historically derailed geothermal exploration.

Fervo says its drilling performance to date fits an expected learning rate of 35% for drilling time improvement, predicting more advances in performance and cost.

Fervo EGS Drilling Learning Curve (spud to actual TD) showing planned 18% learning curve and realized 35% learning curve across all EGS projects (Credit: Fervo Energy).

In 2023, Fervo announced the breakthrough result of its commercial pilot project, Project Red. Using drilling technology honed in the oil and gas industry, Fervo performed a successful 30-day well test, which Fervo says confirms the commercial viability of its drilling technology. The 30-day well test, a standard for geothermal, achieved a flowrate of 63 liters per second at high temperature that enables 3.5 MW of electric production, which Fervo says sets new records for both flow and power output from an enhanced geothermal system.

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