--- title: Offshore Geothermal Energy Pilot Taps Seafloor Heat description: Seattle-based startup Endurance Energy has begun drilling a well 1,500 meters underwater off Oregon's coast near the Juan de Fuca Ridge to test subsea... canonical: https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Offshore Geothermal Energy Pilot Taps Seafloor Heat | daily.dev og:description: Seattle-based startup Endurance Energy has begun drilling a well 1,500 meters underwater off Oregon's coast near the Juan de Fuca Ridge to test subsea... og:url: https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4 og:image: https://api.daily.dev/og/posts/PdPfuPsB4.png og:image:alt: Offshore Geothermal Energy Pilot Taps Seafloor Heat og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Offshore Geothermal Energy Pilot Taps Seafloor Heat **[IEEE Spectrum](https://daily.dev/sources/ieeespectrum)** · 6 min read · 0 upvotes · 0 comments ## Summary Seattle-based startup Endurance Energy has begun drilling a well 1,500 meters underwater off Oregon's coast near the Juan de Fuca Ridge to test subsea geothermal power generation, tapping hydrothermal fluid from an active volcanic region. The pilot uses a 100-kilowatt organic rankine cycle power system called Adélie, focused mainly on data collection rather than power output, transmitting data via existing fiber-optic cables from the NSF's Ocean Observatories Initiative. Experts remain skeptical about offshore geothermal's viability at scale, though Endurance plans a larger 2-megawatt deployment near Tonga by the end of 2027 to help the island nation reduce diesel dependence. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What temperature range is ideal for subsea geothermal drilling to use standard terrestrial materials? The sweet spot is 250 to 350 degrees Celsius, which allows engineers to use conventional terrestrial materials rather than exotic, more expensive components. Endurance Energy's Oregon pilot well accesses hydrothermal fluid at around 250°C from a 60-meter well with a 5-centimeter borehole diameter, much narrower than the 20-30 cm boreholes typical of land-based geothermal wells. _daily.dev surfaces engineering deep dives like this for those tracking novel energy tech approaches._ ### How does Endurance Energy's underwater geothermal power system work? The Adélie system is a 100-kilowatt unit using organic rankine cycle technology, a closed-loop heat transfer process that spins a turbine to generate electricity from hydrothermal fluid piped from a nearby seafloor well. It sits on the ocean floor near Oregon's Axial Seamount, with a submarine robot connecting flexible piping between well and generator, and sends data to shore via existing fiber-optic cables. _engineers evaluating unconventional power generation methods can find similar technical breakdowns on daily.dev._ ### Why is Tonga interested in offshore subsea geothermal energy? Tonga faces high diesel costs since fuel must be shipped from abroad subject to geopolitical price swings, so the island nation partnered with Endurance Energy to deploy a 2-megawatt subsea geothermal unit by the end of 2027 as part of a broader energy independence strategy. Unlike the Oregon pilot, this system will generate actual grid power rather than serve purely as a data-collection test. _daily.dev helps energy-focused readers follow island nations' moves toward diesel alternatives like subsea geothermal._ ## Similar posts on daily.dev - [Geothermal energy turns red hot](https://daily.dev/posts/geothermal-energy-turns-red-hot-ooikjheeo) · MIT News · 0 upvotes · 0 comments - [How an overlooked geothermal plant got a second chance](https://daily.dev/posts/how-an-overlooked-geothermal-plant-got-a-second-chance-yn9bjcore) · MIT Technology Review · 0 upvotes · 0 comments - [Next-generation geothermal energy: Promise, progress, and challenges](https://daily.dev/posts/next-generation-geothermal-energy-promise-progress-and-challenges-a3horq25a) · MIT News · 0 upvotes · 0 comments - [Earthquake Sensors Hear Hurricanes’ Hidden Turbulence](https://daily.dev/posts/earthquake-sensors-hear-hurricanes-hidden-turbulence-f1h5lnr2r) · IEEE Spectrum · 0 upvotes · 0 comments --- Tags: [#climate-tech](https://daily.dev/tags/climate-tech) [View this post on daily.dev](https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Offshore Geothermal Energy Pilot Taps Seafloor Heat","url":"https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4"},"datePublished":"2026-09-24T12:01:32.599Z","dateModified":"2026-09-24T12:01:55.182Z","description":"Seattle-based startup Endurance Energy has begun drilling a well 1,500 meters underwater off Oregon's coast near the Juan de Fuca Ridge to test subsea...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/e5ac1b5bdf3b097a7183261d2576a8b5?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/e5ac1b5bdf3b097a7183261d2576a8b5?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"IEEE Spectrum","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"IEEE Spectrum","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/b123f5e8420e492ab36f6adb30c1793a","url":"https://daily.dev/sources/ieeespectrum"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"climate-tech","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"IEEE Spectrum","item":"https://daily.dev/sources/ieeespectrum"},{"@type":"ListItem","position":3,"name":"Offshore Geothermal Energy Pilot Taps Seafloor Heat"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/offshore-geothermal-energy-pilot-taps-seafloor-heat-pdpfupsb4#faq","mainEntity":[{"@type":"Question","name":"What temperature range is ideal for subsea geothermal drilling to use standard terrestrial materials?","acceptedAnswer":{"@type":"Answer","text":"The sweet spot is 250 to 350 degrees Celsius, which allows engineers to use conventional terrestrial materials rather than exotic, more expensive components. Endurance Energy's Oregon pilot well accesses hydrothermal fluid at around 250°C from a 60-meter well with a 5-centimeter borehole diameter, much narrower than the 20-30 cm boreholes typical of land-based geothermal wells. daily.dev surfaces engineering deep dives like this for those tracking novel energy tech approaches."}},{"@type":"Question","name":"How does Endurance Energy's underwater geothermal power system work?","acceptedAnswer":{"@type":"Answer","text":"The Adélie system is a 100-kilowatt unit using organic rankine cycle technology, a closed-loop heat transfer process that spins a turbine to generate electricity from hydrothermal fluid piped from a nearby seafloor well. It sits on the ocean floor near Oregon's Axial Seamount, with a submarine robot connecting flexible piping between well and generator, and sends data to shore via existing fiber-optic cables. engineers evaluating unconventional power generation methods can find similar technical breakdowns on daily.dev."}},{"@type":"Question","name":"Why is Tonga interested in offshore subsea geothermal energy?","acceptedAnswer":{"@type":"Answer","text":"Tonga faces high diesel costs since fuel must be shipped from abroad subject to geopolitical price swings, so the island nation partnered with Endurance Energy to deploy a 2-megawatt subsea geothermal unit by the end of 2027 as part of a broader energy independence strategy. Unlike the Oregon pilot, this system will generate actual grid power rather than serve purely as a data-collection test. daily.dev helps energy-focused readers follow island nations' moves toward diesel alternatives like subsea geothermal."}}]} ```