Geothermal developer Mazama Energy announced it has created the world’s hottest enhanced geothermal system (EGS) at its pilot site in Oregon’s Newberry Volcano, reaching a bottomhole temperature of 629°F (331°C). The Frisco, Texas-based company said its latest milestone, achieved in late October, sets a new benchmark for geothermal development and advances its goal of generating electricity for less than $0.05/kWh.
Located in the Cascade Range, Newberry is one of the largest geothermal reservoirs in the US. Mazama mobilized a rig to the site in October 2024, converting a legacy well into a water injector and drilling a new deviated producer well to a total measured depth of 10,200 ft. The producer was placed within 6 ft of its planned trajectory, and circulation tests confirmed hydraulic connectivity between the wells. The project was funded in part by a $20-million grant awarded to Mazama last year by the US Department of Energy.
“With geothermal, you get global, round-the-clock energy that is carbon-free, cost-stable, and grid-independent,” Sriram Vasantharajan, CEO of Mazama Energy, said in a statement. “The Newberry pilot provides a blueprint for unlocking baseload, utility-scale, carbon-free energy from the Earth’s crust worldwide—exactly what the next generation of [artificial intelligence] and cloud infrastructure will require.”
Mazama’s pilot featured its proprietary stimulation method known as a “thermal lattice,” which the company detailed in a technical paper (SPE 228048) presented in October at SPE’s Annual Technical Conference and Exhibition .
Building upon the hydraulic fracturing technologies that are used to create EGS wells, Mazama notes that its approach also uses cyclic pressure pulsing below fracture closure pressure to activate “critically stressed natural fractures” near premade tensile fractures. This is done to enhance fracture complexity through induced shear stresses, dilation, and fatigue of fracture tips.
Operational highlights of the pilot included a peak rate of penetration above 100 ft/hr and an average of 76 ft/hr. The company also recorded a record bit run of 2,760 ft through hot volcanic formations with no downhole motor or measurement tool failures. Additional oilfield technologies applied in the pilot included crosslinked fracturing fluids, sliding sleeves, tracers, and fiber-optic diagnostics for real-time monitoring of fracture growth and temperature.
John McLennan, reservoir management lead at the government-funded geothermal project Utah FORGE, added in the company’s announcement, “This is a validation of an integrated development program that has successfully interconnected two slightly deviated wells and circulated a representative working fluid—a fulfillment of a vision from nearly 50 years ago to create a full-scale EGS reservoir which was initiated by Los Alamos National Laboratory at Fenton Hill, New Mexico. This proof of concept opens the door to deeper and hotter opportunities at Newberry and beyond.”
Mazama’s next step is to scale the technology to a 15-MW pilot project using horizontal wells, followed by a 200-MW commercial development at Newberry. Future wells are expected to target temperatures exceeding 750°F (400°C), which the company said could yield up to 10 times the power density while using 75% less water than current EGS methods.
For Further Reading
SPE 228048 Implementation of Thermal Lattice Stimulation Technique in 315°C Geothermal Reservoir To Increase Fracture Complexity by W.M. El-Rabaa, H.H. Abass, G.B. Asher, and N. Siddiqui, Mazama Energy Inc.
