Mazama Energy, which is developing geothermal systems that circulate water through very hot underground rock for utilities and other large power buyers, closed a reported $135 million package of Series B funding and grants, CEO Sriram Vasantharajan told Axios Pro. That is above the $100 million raise Axios said the company was seeking in April, although the new figure bundles equity and grants rather than separating them.
The Frisco, Texas-based company’s model starts below ground. It drills into hot, dry rock, opens connected flow paths between wells, sends water down an injection well and brings heated fluid back through production wells for electricity generation. Mazama calls the reservoir design Thermal Lattice; a separate modeling system, HeatHarvester, is meant to forecast how the wells will perform over time so future output can be contracted.
At Newberry in central Oregon, Mazama says its 2025 pilot drilled 10,200 feet and opened pathways in rock measured at 629°F. That is below the roughly 705°F point where water becomes supercritical, but well above the temperatures used by conventional engineered geothermal systems. Its Athena appraisal well is now targeting rock above 752°F to collect cores and map the heat, strength and structure underground.
The next stage, Ceres, is designed as two horizontal wells linked by an engineered reservoir. Mazama says the pair should circulate water at commercial rates and generate 15 megawatts in initial testing. Its site describes Ceres as the module for a planned 200-megawatt Newberry plant, with first power targeted for 2029 and full output in 2030.
The economic bet is simple to state and hard to prove in the field: hotter rock should yield more electricity from each expensive well. Mazama projects five to 10 times more power per well than conventional engineered geothermal and fewer wells for the same output. The 2025 pilot showed water could circulate underground; Ceres is supposed to test whether that result can become repeatable generation at commercial flow rates.