The well was drilled to a true vertical depth of 15,765 feet and is projected to reach a bottomhole temperature of 520 °F after full thermal equilibration. Fervo completed the Sugarloaf well in just 16 drilling days, representing a 79% reduction in drilling time compared to the US Department of Energy baseline for ultradeep geothermal wells.
While drilling what is Fervo’s hottest and deepest well to-date, the company was able to achieve multiple drilling performance records, including a maximum bit run length of 3,290 feet, a maximum average rate of penetration (“ROP”) of 95 feet/hour, and an instantaneous ROP of over 300 feet/hour at depths greater than 15,000 feet. These results expand the window for commercial viability of EGS into a significantly deeper and hotter regime, paving the way to deploy the technology outside of the western US.
In parallel, Fervo has obtained an independent geothermal reserves report from worldwide consulting firm DeGolyer & MacNaughton for Cape Phase I. This comprehensive technical and economic evaluation of Fervo’s development plan provides external verification on Fervo’s ability to deliver contracted clean energy volumes to customers including Shell Energy and Southern California Edison.
DeGolyer & MacNaughton’s independent estimates of heat-in-place and reserves involved a comprehensive review of Fervo’s drilling data, geologic models, and production test results. The report highlights that Fervo’s proprietary EGS design successfully unlocks thermal recovery factors in the range of 50 to 60%, tripling the amount of useful thermal energy reserves compared to conventional geothermal technology.
The report confirms that the Cape Station project area can support over 5 GW of development at depths of up to 13,000 feet. The new Sugarloaf drilling results are expected to increase Cape’s resource potential even further.
Various geothermal resource evaluation and grid modeling studies – including recent reports by the US Geological Survey, Princeton University, and National Renewable Energy Laboratory – have now aligned that there are hundreds of gigawatts of opportunity for geothermal deployment in the range of 10,000 to 20,000 feet and 400 to 600 °F.
“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.”
As US power demand accelerates - driven by AI, electrification, and grid reliability needs - Fervo’s ability to unlock firm, carbon-free energy from heat reservoirs miles underground positions it as a core contributor to the American energy mix.
