· Investment Strategies · 4 sources · Verified
Mazama Energy’s $135M: Series B, Grants, or Both?
Mazama announced $135 million of new capital on September 17, 2026, including an oversubscribed Series B led by Centaurus and Doerr Capital. Axios reports Series B funding and grants. Valuation was not disclosed. Newberry’s 331°C well is the proof; commercial power is not.
By Venture Capital Tracker Editorial
Mazama Energy announced $135 million of new capital on September 17, 2026, including an oversubscribed Series B led by Centaurus Capital (John Arnold) and Doerr Capital. Khosla Ventures and Gates Frontier returned. ConocoPhillips and Shell Ventures joined. Valuation was not disclosed. GlobeNewswire and Canary Media treat $135 million as a bag that includes Series B. Axios says Series B funding and grants. TechCrunch called it a Series B. Do not flatten that into “$135 million of priced equity.”
Hottest disclosed EGS well, still pre-power. The money is to prove 15 MW horizontal wells — not to match Fervo’s public offtake.
Key facts
- Company
- Mazama Energy (mazamaenergy.com) — Frisco/Dallas; Newberry, Oregon field
- Amount
- $135M new capital including Series B (company). Axios: funding and grants
- Leads
- Centaurus Capital, Doerr Capital. **
- Returning
- Khosla Ventures (incubator), Gates Frontier
- Strategics
- ConocoPhillips, Shell Ventures
- Also named
- SiteGround Capital, H. Barton Asset Management, Rothschild Foundation
- Technical print
- 629°F / 331°C EGS (2025); second well 10,350 ft ~80% faster
- Next
- Project Ceres (DOE-supported): 15 MW/well; power test 2027
- Company targets
- >10 GWe Newberry resource (vs Khosla’s 5 GW comment last year); 200 MW first site by 2030
- Valuation / ARR / offtake $
- Not disclosed
What the wells actually show
Mazama is not selling steam from a natural aquifer. It fractures hot, dry rock and wants supercritical fluid around 750°F / 400°C, which it says can deliver up to 10× conventional geothermal output per well. CEO Sriram Vasantharajan told Canary that superhot rock is “almost essential” for geothermal to compete with fossil fuels.
The 2025 Newberry well is a temperature record, not a PPA. Ceres is the commercial blueprint: horizontal wells, DOE support, drilling later this year, testing early next year. Rig time matters — Canary notes >$100,000/day. An 80% faster second well is the operating tell, if it holds at 15,000 feet.
Mazama vs Fervo (and storage)
| Mazama | Fervo | Form Energy | |
|---|---|---|---|
| Status | Private, pre-power | Public FRVO; sells power | Private; iron-air storage |
| Job | Superhot EGS at Newberry | EGS at cooler commercial temps | Multi-day batteries |
| Last print | $135M bag, Sep 2026 | IPO ~$1.89B, May 2026 | $750M Series G, Aug 2026 |
Same “firm clean watts for AI load” tape. Different product. Form stores; Mazama and Fervo try to generate. Fervo already cleared a public-market diligence bar Mazama has not.
Canary places Sage Geosystems (Texas pilot power) and Quaise (also Newberry; ~$180M in August, not covered here) on the same map. Do not treat those as Mazama closes.
What is not proven
- Equity vs grant split inside $135M.
- Valuation, offtake, interconnection, or well cost at 400°C.
- Whether 10 GWe resource potential becomes 200 MW by 2030.
- Independent verification of “hottest EGS” beyond company/Khosla claims.
Practical takeaway
- Founders (geothermal): Sell well productivity and time-to-depth, not terawatt TAM. Arnold’s quote is about innovation required — not a signed offtake.
- Investors: Diligence the grant mix and whether Ceres produces electrons, not just hotter rock.
- Operators: Relevant if you need 24/7 western U.S. clean supply and can wait past a 2027 demo.
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Editorial note: AI tools assisted with research, structure, or drafting. Venture Capital Tracker retains human editorial responsibility for factual accuracy, relevance, and source quality before publication.
