Senior Mechanical Engineer (Valves & Components)

The posting, as Endurance Energy wrote it

ABOUT ENDURANCE

Endurance is building the world's first modular subsea geothermal power plants, converting vast thermal resources under the ocean into gigawatts of baseload power. Backed by Founders Fund, Felicis, First Round Capital, and Point72 Ventures, our founding team includes veterans from SpaceX, Helion, Blue Origin, and Apple. We have completed multiple deep-ocean deployments to subsea volcanoes and are launching a long-term demonstration project this fall. By leveraging modular design, manufacturing scale, efficient drilling, and latent cooling on the seafloor, we are pioneering a new category of energy that outperforms traditional sources on environmental impact, deployment speed, and cost.

The Role

Our seafloor power plants move 250-350 °C geothermal fluid through a closed loop 1-3 km underwater, surrounded by near-freezing seawater at 100-300 bar. Every valve, seal, fitting, compensator, and filter in that loop has to hold hot, corrosive, scaling fluid on one side and the deep ocean on the other, for years, with no one able to service it. Nobody makes these parts off the shelf. We design, build, test, and deploy them.

In this role you will focus on the fluid components of the plant: isolation, check, control, and relief valves; seats and seals; fittings, manifolds, and compensators; filters and strainers. You will share that scope with a few other engineers, and specific components will be yours end to end. Most of the work is clean-sheet design. You will size seats and springs, choose materials that survive chlorides, sulfides, and silica scaling at temperature, and build the hot-fluid test rigs that qualify your hardware. This is a natural fit for someone who has designed propulsion valves and wants to apply that experience to a hotter fluid, a higher ambient pressure, and a much longer mission.

Your First Year

Help deliver the fluid-component set for our first commercial system, the first subsea geothermal plant to put power on a grid: designed, built, qualified in our own test cells, and operating on the seafloor. The components you own become the baseline for the plants that follow.

How We Work

Our mechanical engineering team is a small group of senior and principal engineers who split the plant's hardware between them. Each engineer owns their hardware end to end: requirements, design, drawings, build, test, and deployment. Principal engineers own the plant architecture, and you will be part of those decisions. We are looking for people who have built hardware, debugged it in the lab or the field, and want to own the result.

Responsibilities

• Own specific fluid components in the working-fluid loop from requirements through design, qualification, and field performance
• Design valves (isolation, check, control, relief) and sealing systems for 250-350 °C fluid with 100-300 bar external seawater pressure
• Select and qualify materials for hot chloride, sulfide, and silica-scaling environments: nickel alloys, dupl

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gineering competition team (Formula SAE, Baja SAE, RoboSub, rocketry, or similar) or an equivalent self-directed hardware project

COMPENSATION, BENEFITS, & PERKS

As a pre-revenue startup, Endurance Energy offers competitive base salaries and generous equity packages for full-time employees. Final base salary will be determined by an array of factors including internal equity, job-related knowledge, skills, and work experience.

A key aspect of our compensation philosophy is that value creation should be aligned with rewards. Right now this means equity is a significant portion of every full-time employee's compensation. As the company matures, there will be continued evolution and changes to the total rewards and total compensation package. What will always be true is that if we win, we win together. Equity is granted to every full-time employee as a meaningful piece of ownership. We believe the people building the company should share directly in the value they create.

In addition to a competitive base salary and equity, employees will receive all of our other great benefits and perks, including:

• Benefits: Health, Dental, and Vision insurance coverage
• Time Away: Flexible PTO including 12 paid company holidays
• Global Fieldwork: Travel to fascinating deployment sites along oceanic ridges in locations like the Pacific Northwest, Hawaii, Iceland, Japan, New Zealand, and the Azores
• Hands-on Experience: Participate in sea trials and deployment operations in partnership with leading oceanographic institutions
• Cutting-edge Development: Work with technology that spans high-power electronics, marine systems, and clean energy
• Impactful Work: Help solve one of the world's most pressing challenges
• Dive Certification: Company-sponsored recreational dive certification
• Other Perks: Access to the company boat, free meals and snacks, and the list goes on!

If you’re selected for consideration, a recruiter will be able to discuss in greater detail.