Endurance Energy completes $54 million funding round to develop subsea geothermal technology
Subsea geothermal systems by Endurance Energy (source: Endurance Energy)
Carlo Cariaga
15 Jun 2026
US-based Endurance Energy has raised $54 million in Series A funding to advance the development of their technologies for subsea geothermal systems.
U.S.-based startup Endurance Energy has announced the successful completion of a USD 54 million Series A funding round to develop its technology to harness energy from subsea geothermal systems. According to the company, the funding will allow them to transition from prototype to full-stack systems and scale their offshore operational capability.
The funding round was led by Founders Fund, with participation from Ascend, Construct Capital, Felicis, First Round Capital, Point72 Ventures, Riot Ventures, and Voyager Ventures.
Founded by former SpaceX engineer Andrew Redd, Endurance Energy is developing technology to harness geothermal energy from subsea volcanic systems. According to the company, it has so far already completed four prototype deployments to deep sea volcanic systems at depths up to 3300 meters and hydrothermal temperatures up to 386°C. They are now also on-track to deploy a 100 kW generator at the Juan de Fuca ridge off the coast of the Pacific Northwest region of North America in the coming Fall.
Earlier this year, Endurance Energy signed an agreement with the Government of Tonga to explore opportunities for developing subsea geothermal resources within the Kingdom’s territorial waters. The partnership aims to assess the potential of offshore volcanic systems as a source of reliable renewable energy for the island nation.
Evaluation of geothermal prospects in offshore settings had already been undertaken in previous years, with work being mainly focused in the North Sea region. However, this may be the first time that a funded startup is developing and deploying such technologies. While the geologic potential is certainly present, it remains to be seen how the economics of subsea geothermal will be optimizing considering the costs of subsea power distribution and the proximity to sizable onshore markets.
Source: Endurance Energy via Linkedin
