What happened
Mazama Energy raised $135M in an oversubscribed Series B on September 17, 2026, led by Centaurus Capital and Doerr Capital, to scale superhot rock geothermal at Newberry, Oregon.
Mazama Energy announced $135 million in new capital on September 17, 2026 to accelerate superhot rock geothermal commercial development. The oversubscribed Series B was led by Centaurus Capital (founded by John Arnold) and Doerr Capital, with ConocoPhillips and Shell Ventures joining; Khosla Ventures and Gates Frontier made repeat investments.
Mazama's second well, Project Athena, reached 10,350 feet in 15 days in September 2026 — about 80% faster than its 2025 well — and is drilling toward approximately 15,000 feet at 750°F (400°C). At that temperature, water becomes supercritical, enabling up to 10 times the power of a conventional 390°F well while using 75% less water and 80% fewer wells than conventional geothermal developments.
The new capital funds Project Ceres, supported by the U.S. Department of Energy, which will advance horizontal well development in superhot rock toward 15 MWe of capacity per well and demonstrate power generation in 2027. Mazama is targeting independent certification of more than 10 GWe of resource potential at its Newberry, Oregon site.
Sriram Vasantharajan, CEO of Mazama Energy, previously co-founded Quaise Energy, which developed ultra-deep geothermal mining technology. At Newberry, we have demonstrated the critical pieces together: extreme-temperature drilling, reservoir creation and heat harvesting, at temperatures no other engineered geothermal system has achieved.
What happened
Mazama Energy announced $135 million in new capital on September 17, 2026 to accelerate superhot rock geothermal commercial development. The oversubscribed Series B was led by Centaurus Capital (founded by John Arnold) and Doerr Capital, with ConocoPhillips and Shell Ventures joining; Khosla Ventures and Gates Frontier made repeat investments.
How the drilling is changing
Mazama's second well, Project Athena, reached 10,350 feet in 15 days in September 2026 — about 80% faster than its 2025 well — and is drilling toward approximately 15,000 feet at 750°F (400°C). At that temperature, water becomes supercritical, enabling up to 10 times the power of a conventional 390°F well while using 75% less water and 80% fewer wells than conventional geothermal developments.
What is next
The new capital funds Project Ceres, supported by the U.S. Department of Energy, which will advance horizontal well development in superhot rock toward 15 MWe of capacity per well and demonstrate power generation in 2027. Mazama is targeting independent certification of more than 10 GWe of resource potential at its Newberry, Oregon site.
Why it matters for me
The capital funds Project Ceres toward 15 MWe per well by 2027 and certification of 10+ GWe resource potential — potentially reshaping clean baseload power with 10x density and 75% less water.
Money
Clean Energy Investors
$135M Series B signals strong investor confidence in superhot rock geothermal commercial viability
Daily Life
Energy Policy Watchers
Supercritical geothermal at 400°C could deliver 10x power with 75% less water, reshaping clean baseload
Work Career
Tech Startup Followers
DOE-supported Project Ceres could set federal precedent for advanced geothermal demonstration funding
What to remember
$135M puts superhot-rock geothermal one well-depth away from commercial scale at 400°C.
Mazama Energy raised $135M to drill 15,000 ft at 400°C in Oregon — superhot rock geothermal could deliver 10x power with 75% less water.
Verified sources (5)
Khosla-backed Mazama Energy just raised $135M to drill deeper into super-hot-rock geothermal
↗Mazama Energy Raises $135 Million to Scale the World's Hottest Engineered Geothermal System
↗Mazama Energy Raises $135 Million to Scale the World's Hottest Engineered Geothermal System
↗Mazama Energy Raises $135 Million to Scale the World's Hottest Engineered Geothermal System
↗Mazama Energy Raises $135 Million to Scale the World's Hottest Engineered Geothermal System
↗Claims and linked sources
7 claimsMazama Energy announced $135 million in new capital on September 17, 2026 to accelerate superhot rock geothermal commercial development.
The oversubscribed Series B was led by Centaurus Capital (John Arnold) and Doerr Capital, with ConocoPhillips and Shell Ventures joining; Khosla Ventures and Gates Frontier repeated.
Project Athena reached 10,350 feet in 15 days, about 80% faster than the 2025 well, drilling toward ~15,000 feet at 750°F (400°C).
At 750°F (400°C) water becomes supercritical, enabling up to 10x power of a 390°F conventional well, 75% less water, 80% fewer wells.
Project Ceres (DOE-supported) advances horizontal well development toward 15 MWe per well, demonstrating power generation in 2027.
Mazama targets independent certification of more than 10 GWe resource potential at its Newberry, Oregon site.
CEO Sriram Vasantharajan previously co-founded Quaise Energy, which developed ultra-deep geothermal mining technology.
Community signals
Signal-only · not reporting“At Newberry, we have demonstrated the critical pieces together: extreme-temperature drilling, reservoir creation and heat harvesting, at temperatures no other engineered geothermal system has achieved.”
“Power is the constraint on everything we're trying to build this decade. We backed Mazama early because geothermal can be the planet's largest source of clean, 24/7 power.”
“The world needs vastly more electricity, and we need to produce it cleanly and affordably. Superhot geothermal has the potential to be a major new source of 24/7 clean power.”