# Endurance Energy

> Develops modular seafloor geothermal generators for coastal and industrial electricity demand.

## Why it is interesting

The company claims its offshore prototype produced net-positive power from a natural hydrothermal vent in September 2026, a different approach from conventional onshore geothermal. It has disclosed a $54 million Series A.

## Profile

- **Latest funding:** Series A — $54M (June 2026)
- **Latest known valuation:** Not publicly disclosed
- **Total disclosed equity funding:** $54M
- **Stage:** series-a
- **Status:** private
- **Industries:** climate-tech, deep-tech, hardware-semiconductors
- **Coverage:** full
- **Last updated:** 2026-10-29
- **Latest funding investors:** Founders Fund, Riot Ventures

## Key facts

- June 2026: reported $54 million Series A led by Founders Fund, with Riot Ventures among participants.
- September 2026: deployed Adélie prototype at the Axial Seamount hydrothermal vent off Oregon and reported positive net electrical output.
- Developing a 2 MW commercial-scale generator; first power from a proposed Tonga deployment is targeted for 2027, not yet achieved.
- Expanded into a 25,000-square-foot Seattle R&D and production facility in 2026.

## Funding history

- Series A · $54M · June 2026
  Source: https://geothermaltransition.com/news/north-america/endurance-energy-raises-funds-for-subsea-geothermal-ambition

## Investors in our directory

- https://venturecapitaltracker.com/fund/founders-fund
- https://venturecapitaltracker.com/fund/riot-ventures

**By:** [Venture Capital Tracker](https://venturecapitaltracker.com/editorial-policy)
**Last updated:** October 29, 2026

**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.

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Source: https://venturecapitaltracker.com/startup/endurance-energy