Director of Mechanical Engineering

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

• Pragmatic Optimism


• Excellence without Ego


• Proactive Collaboration

We are seeking a Director of Mechanical Engineering to lead a substantial portion of the team scaling the Linear Generator — a first-of-kind distributed power platform that converts a low-temperature, flameless reaction directly into electricity using high-frequency linear motion instead of rotating machinery. The system integrates reciprocating pressure-driven assemblies, air-spring return chambers, precision alignment systems, and linear electromagnetic machines within a modular 250 kW-class packaged unit. It operates under cyclic loads, tight sealing constraints, thermal gradients, structural dynamics, and grid-interactive performance requirements typical of commercial power generation equipment.

Reporting to the VP of Mechanical Engineering, this role is being created to expand leadership capacity, elevate risk visibility, and enable disciplined scaling of a growing hardware portfolio.

You will own ~40-50% of the mechanical organization’s active projects and lead ~25 direct and indirect reports, with scope expected to grow. Your teams will oversee multiple core subsystems that are tightly coupled and reliability-critical.

Success requires both deep mechanical intuition and strong organizational leadership. You will strengthen technical rigor, improve prioritization across 50+ active efforts, and build execution systems that allow the organization to scale without sacrificing engineering excellence.

• Leadership of ~25 engineers (direct and indirect), including managers


• 40-50% of the mechanical project portfolio


• Accountability for multiple core subsystems


• Early identification and mitigation of subsystem and program-level risks


• Strong engineering review discipline (FMEA, DVP&R, tolerance analysis, ECO governance)


• Partnership with Manufacturing and Supplier Quality to support at-scale production


• Development of future engineering leaders

• 18+ years delivering complex industrial or energy hardware


• Experience in high-volume, at-scale environments


• Leadership of 15-30+ engineers (direct + indirect)


• Strong judgment around technical and program risk


• Ability to balance architecture evolution with production realities


• Management experience required; Director title not mandatory


• Senior-level design credibility to lead experienced engineers

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.

This position is onsite at our Menlo Park HQ. The salary will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base salary, Mainspring offers pre-IPO stock options + benefits.