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Overview
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.
About Mainspring Energy
Industries
Hardware
Industrial & Manufacturing
Energy
Company Size
501-1,000
Company Stage
Series F
Total Funding
$726M
Headquarters
Menlo Park, California
Founded
2010
Simplify's Take
What believers are saying
- Chattanooga project converts wastewater methane to 1.5 MW, cutting $300K monthly costs.
- Utah Municipal Power Agency contracts 48 MW project starting 2027 with 30% tax credit.
- $258M Series F funding scales operations for AI data center demand.
What critics are saying
- Verdagy Moss Landing failure halts hydrogen supply within 6-12 months.
- GE Vernova LM2500 turbines undercut with 20-30% lower capex in 12-24 months.
- Pennsylvania facility delays from labor shortages block 2026 shipments.
What makes Mainspring Energy unique
- Linear Generator uses flameless reaction with two moving parts for oil-free operation.
- Fuel-flexible design runs on natural gas, biogas, hydrogen, ammonia, and propane seamlessly.
- Scalable from 250 kW modules to over 100 MW blocks with near-zero NOx emissions.
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Funding
Total Funding
$726M
Above
Industry Average
Funded Over
5 Rounds
General CatalystBenefits
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
6 month growth
↑ 0%1 year growth
↑ 2%2 year growth
↑ 1%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.
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.
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
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
Mainspring Energy has raised $258 million in a Series F financing round to expand its linear generator power business and operations.
Mainspring Energy is Hiring for 43 Jobs on Simplify!
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About Mainspring Energy
Industries
Hardware
Industrial & Manufacturing
Energy
Company Size
501-1,000
Company Stage
Series F
Total Funding
$726M
Headquarters
Menlo Park, California
Founded
2010
Mainspring Energy is Hiring for 43 Jobs on Simplify!
Find jobs on Simplify and start your career today