Senior R&D Engineer

Company: Renewell Energy
Location: Denver
Posted on: February 13, 2026

Job Description:

Job Description Job Description Join Renewell and drive innovation at the cutting edge of the energy storage and well remediation sectors. Our breakthrough technology tackles the climate crisis by converting inactive oil and gas wells into gravity-based energy storage systems—providing reliable renewable power while cleaning up millions of idle wells across the U.S. This is a rare opportunity to be one of the early hires at a mission-driven startup that is entering a promising growth phase with ~$15M raised to-date (VCs, US DOE (ARPA-E), CEC, etc.), regulations recently changed in 3 states, and deployment poised to 5-11x in the next 2 years. If you’re excited by hands-on engineering, creative problem-solving, and scaling a revolutionary technology in a high-paced environment, let’s talk. Role: As the Senior R&D Engineer, you’ll lead the design, prototyping, testing, and optimization of our 3 novel energy storage systems (only 1 is public). You’ll own key technical projects, collaborate with internal and external partners, and help transition our concepts into commercial-ready solutions. The role is highly hands-on, dynamic, and growth-oriented—perfect for engineers who thrive on tackling big technical challenges with creativity and rigor. As part of a high-growth startup, you will be challenged to rapidly expand your skillset, with ample opportunity to grow into a leadership role. Responsibilities: Design, build, and iterate on prototype systems that repurpose idle wells for energy storage Develop technoeconomic models to evaluate design trade-offs and system economics Lead lab and field testing, including test plan design, setup, execution, and analysis to maximize efficiency, lifetime, safety, and economic benefit of this technology Collaborate across mechanical, electrical, and software teams for system integration Manage vendors, contractors, and consultants to support R&D and pilot deployments Travel to vendors, customers, and installation sites (10–25%) For further background on Renewell, please take a look at our website (renewellenergy.com) or this mini-documentary: https://tinyurl.com/2p82trd9 Requirements Required skillset/experience: Minimum 3-5 years industry experience Hands-on mechatronic system development Creative problem solving skills and scientific curiosity Location This job will begin remote, but we plan to bring the engineering team into an office between May and December of 2026. The location of that office has not been finalized, but it will either be Los Angeles or Denver. Benefits Renewell Energy values collaborative, growth-minded, innovative thinking and finding ways to have fun while maintaining a culture of excellence. We offer competitive compensation and benefits including: Salary range for this position (depending on experience and skillset): $100k to $250k equity Silver-level family health coverage (medical, dental) Employer 401(k) contributions, up to 5%, full match Life insurance and disability coverage Renewell Energy is an equal opportunity employer and we welcome applications from all backgrounds regardless of race, color, religion, sex, national origin, ancestry, age, marital status, sexual orientation, gender identity, veteran status, disability, or any other classification protected by law. No fee will be paid to third parties who submit unsolicited candidates directly to our team.

Keywords: Renewell Energy, Littleton , Senior R&D Engineer, Engineering , Denver, Colorado