GreenFire The Geysers

Executive Overview

The GreenFire Geysers project is a closed-loop geothermal demonstration conducted by GreenFire Energy in partnership with Calpine Corporation (through Geysers Power Company, LLC) at The Geysers geothermal field in the Mayacamas Mountains, California — the world's largest geothermal field, generating approximately 725 MW across 13 Calpine-operated power plants covering 45 square miles. The project was funded by more than $2.7 million from the California Energy Commission through the BRIDGE programme. A downbore heat exchanger was installed in a low-output well approaching idle status. Two seven-day production tests were completed, with step-change testing in forward- and reverse-flow configurations, yielding sustained flow rates of 300–350 gallons per minute at 154°C in a stable closed-loop system. A commercial project in Japan was subsequently launched, confirming the technology's international validation pathway.

How It Works & Differentiation

GreenFire's GreenLoop system inserts a sealed coaxial or U-tube downhole heat exchanger into existing wellbore infrastructure. A working fluid circulates in a closed loop, extracting heat from the formation without producing any formation fluid. At The Geysers, the system uses an Organic Rankine Cycle (ORC) subsystem, using a working fluid that boils at a lower temperature than water, enabling power generation while preventing water loss to atmosphere. This is directly differentiating at The Geysers: the field currently injects approximately 13 million gallons per day of treated municipal wastewater to maintain steam pressure, and water loss at conventional wells is a structural operational constraint. Closed-loop operation eliminates that loss pathway. The Geysers historically peaked at approximately 2,000 MW in 1987; bringing it back toward its historic peak would be equivalent to adding approximately 1 GW of firm renewable capacity without any new drilling.

Commercialization & Traction

The Geysers project is GreenFire's most significant U.S. field demonstration in an active commercial geothermal operation, validating GreenLoop in a steam-dominated (vapour-phase) reservoir. Calpine's 13 plants at The Geysers generate approximately 725 MW and prevent approximately 2.4 million tonnes of CO₂ emissions annually — equivalent to removing approximately 432,500 cars from roads. The existing well infrastructure, power lines, and grid connections at The Geysers dramatically reduce deployment costs compared to greenfield geothermal. This is GreenFire's second CEC-funded geothermal demonstration, following the 2017 Coso closed-loop grant.

Scalability & Strategic Context

The GreenLoop Geysers demonstration addresses the core long-term challenge of the field: its productive capacity has declined from 2,000 MW to 725 MW over 35 years as natural steam pressure has dropped. GreenFire's closed-loop approach offers a potential pathway to restore productivity in marginal and idle wells without additional drilling or water injection costs. If the technology scales to even a fraction of The Geysers' approximately 370 wells, the productive capacity implications would be significant. The Japan commercial project launch following the Geysers demonstration confirms that GreenFire is using California field validation to underpin international commercial expansion.