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Mainspring Energy

Onsite linear generators for scalable power

Electrical Engineer - Power Electronics

Full-Time
$124k - $147k/yr
Junior, Mid
Bachelor's, Master's, PhD
Menlo Park, CA, USA
HybridHybrid work arrangement in Menlo Park.
Electrical EngineeringPower Systems Engineering

About the job

Requirements
  • A Bachelor's degree or higher in Electrical Engineering.
  • 2-5 years of experience developing power electronics technologies.
  • Strong electronics design fundamentals, including selecting components and producing schematics from concept-level design details.
  • Examples of ownership of a power electronics design project.
  • Circuit board design experience.
  • Familiarity with schematic capture and power converter circuit modeling and simulation tools.
  • Knowledge of power electronics control theory.
  • Proficiency with electrical engineering tools, including oscilloscopes, power analyzers, network analyzers, and signal generators.
  • Experience with power semiconductor selection, gate drive, and protection circuit design.
  • Ability to work independently on an electronics design project.
  • Clear verbal and written communication skills.
  • Hands-on hardware development experience.
  • Ability to collaborate effectively across teams and with people of varied backgrounds and personalities.
Responsibilities
  • Design custom power electronics hardware that enables key functions of the Linear Generator.
  • Bring up, validate, and qualify power electronics designs.
  • Troubleshoot complex hardware issues in the test lab, production floor, and fielded units.
  • Collaborate with the new production introduction team and external suppliers to improve designs for manufacturability and testability.
  • Partner with reliability engineers to improve electrical hardware reliability.
  • Serve as an expert on the owned hardware systems.
Desired Qualifications
  • Experience designing high-voltage systems in the 480 VAC or 800 VDC range.
  • Experience designing kilowatt-level power electronics.
  • Experience across the full hardware development life cycle, from requirements development through manufacturing support.
  • Experience working at a startup or in a rapid-development environment.
  • Experience with Altium.

About the company

Onsite linear generators convert straight-line motion into electricity using a flameless, low-temperature air–fuel reaction that drives magnets through copper coils. With only two moving parts and an oil-free air-bearing, maintenance is reduced, and the system runs on multiple fuels (natural gas, biogas, hydrogen, ammonia, or propane) with seamless switching. Modules scale from about 250 kW to over 100 MW and produce near-zero NOx without after-treatment. The energy-as-a-service model lets customers install with no upfront cost and pay for the energy used, serving commercial and industrial customers, data centers, utilities, and microgrids, with financing and deployment partners like NextEra Energy Resources and Schneider Electric; the company has attracted major investors and is expanding manufacturing to support growth.

Company Size

501-1,000

Company Stage

Series F

Total Funding

$726M

Headquarters

Menlo Park, California

Founded

2010

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Simplify's Take

What believers are saying

  • UMPA selected Mainspring for 48 MW in February 2026, validating utility demand.
  • CalBio expanded to 5.3 MW across five California sites in February 2026.
  • Chattanooga and Verdagy projects in 2025-2026 prove wastewater methane and hydrogen use cases.

What critics are saying

  • Mainspring still depends on the 2027 Pittsburgh plant; permitting or construction slips delay volume.
  • Data-center and utility wins stay project-based, so cancellations can crush forecasted revenue.
  • A hydrogen commercialization miss would undercut its fuel-flexibility thesis against diesel and turbines.

What makes Mainspring Energy unique

  • Tom Linebarger joined June 2026, giving Mainspring Cummins-scale utility and data-center credibility.
  • Its linear generators run biogas, hydrogen, ammonia, propane, and natural gas without downtime.
  • Pennsylvania factory plans target 1,000 generators yearly, supporting fast domestic supply scaling.

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Benefits

Health Insurance

Dental Insurance

Vision Insurance

Unlimited Paid Time Off

Flexible Work Hours

Remote Work Options

Paid Vacation

401(k) Retirement Plan

Conference Attendance Budget

Professional Development Budget

Wellness Program

Mental Health Support

Gym Membership

Phone/Internet Stipend

Home Office Stipend

Growth & Insights and Company News

Headcount

6 month growth

0%

1 year growth

0%

2 year growth

1%
PR Newswire
Jun 10th, 2026
Mainspring appoints former Cummins CEO Tom Linebarger as CEO, founder Shannon Miller as president

Mainspring Energy has appointed Tom Linebarger, former Cummins chairman and CEO, as chief executive, whilst founder Shannon Miller transitions to president. The move positions the company for expansion into AI data centre and utility power infrastructure markets. Linebarger spent 30 years at Cummins, navigating growth and entry into new markets including battery electric powertrains and data centre power. He joined Mainspring's board 14 months ago and was recruited by Miller after demonstrating the impact he could deliver. Founded in 2010, Mainspring manufactures fuel-flexible, low-emissions linear generators. The company began commercial shipments in 2020 and now has hundreds of megawatts in advanced development and field operations, serving Fortune 500 companies, data centres and utilities. Partners include AEP, NextEra Energy Resources and Schneider Electric.

Yahoo Finance
Mar 9th, 2026
Chattanooga converts wastewater methane into electricity to cut $300K monthly energy costs

Chattanooga's Moccasin Bend Environmental Campus is partnering with Mainspring Energy to convert wastewater methane into electricity, aiming to cut roughly one-third of its $300,000 monthly energy costs. The project will install six linear generators this year, producing 1.5 megawatts initially, with plans to double capacity to three megawatts following campus upgrades. The system will eliminate routine methane flaring whilst strengthening grid reliability by generating power on-site. Once fully operational, it will rank amongst the largest municipal biogas-to-power projects in the Southeast. Mainspring's low-emission generators can run on biogas, natural gas, hydrogen or ammonia, allowing fuel source flexibility. The project reflects growing municipal focus on infrastructure resilience whilst reducing emissions and stabilising long-term energy costs for ratepayers.

PR Newswire
Feb 9th, 2026
Utah Municipal Power Agency selects Mainspring for 48MW local power generation project

Utah Municipal Power Agency has selected Mainspring Energy to supply 48 MW of dispatchable local generation capacity using linear generators. The greenfield project in central Utah is scheduled to begin operations in 2027. UMPA chose Mainspring's technology to address rising electricity demand whilst meeting sustainability and cost objectives. The linear generators offer emissions below 1.5 ppm NOx, rapid factory manufacture and installation, and qualify for a 30% investment tax credit. The modular design ensures high availability during maintenance events. Mainspring began commercial shipments of its linear generators in 2020 and has hundreds of megawatts in development. The company partners with major energy firms including AEP, NextEra Energy Resources and Schneider Electric.

Renewable Energy Magazine
May 30th, 2025
Verdagy To Supply Hydrogen To Mainspring Energy For Its Linear Generators

Friday, 30 May 2025Verdagy’s Moss landing plant has been in operation for four years with more than 20,000 hours of operation with commercial cells and over 200 tons of hydrogen produced. The fully automated, 24/7 plant provides Mainspring constantly available, low-cost hydrogen as a fuel for power generation.The collaboration establishes a ready hydrogen fuel source for Mainspring’s fuel-flexible linear generators and provides Verdagy with onsite offtake for its hydrogen and electricity to support its electrolysers operation. The two companies expect to begin operations by summer 2025.“Verdagy and Mainspring Energy are demonstrating how we can improve energy resiliency for the electrical grid, datacentres and other applications” said Marty Neese, CEO of Verdagy. “This collaboration with Mainspring Energy is a compelling model for clean, flexible, on-site power solutions.”Building on its expertise in producing clean hydrogen at scale, Verdagy is now reducing operational costs by converting hydrogen into power and cycling it back into the facility.“This agreement presents an excellent opportunity for Mainspring to showcase our linear generator’s capabilities operating on hydrogen and for Verdagy to demonstrate its high resiliency industrial grade production operation” added Shannon Miller, Mainspring CEO and Founder. “We’re pleased to partner with Verdagy to highlight the significant potential of hydrogen in power generation.”By powering Mainspring’s Linear Generators with hydrogen produced on-site, the installation demonstrates how low-carbon energy can be deployed at the point of use – critical for enhancing resiliency in grid constrained and mission-critical environments. This co-located model for hydrogen consumption to generate power is crucial as grid constraints grow.For additional information:VerdagyMainspring Energy

PR Newswire
May 7th, 2025
Kinsley Energy Systems Partners With Mainspring Energy To Solve Critical Grid Challenges

EAST GRANBY, Conn., May 7, 2025 /PRNewswire/ -- Kinsley Energy Systems, a leader in onsite power solutions with a 60-year legacy in the energy industry, announces a new partnership with Mainspring Energy to deliver linear generators to commercial and industrial businesses and other high-demand facilities across the Northeast, mid-Atlantic and beyond. This collaboration combines Kinsley's unmatched onsite energy expertise and field service capabilities with Mainspring's innovative linear generator technology