A new way to save with reliable and resilient on-site generation

NextEra Energy Resources and Mainspring offer a new way to achieve energy cost savings with an innovative, low-emissions technology.

Cost savings are achieved with the linear generator by offsetting both energy and demand charges. The linear generator is a low cost investment as standard materials and processes are used in its manufacturing and simplified maintenance. Once installed, the linear generator can be efficiently operated on a variety of fuels, including low cost natural gas or renewable biogas. When paired with a renewable energy resource such as solar, the linear generator allows customers to maximize the value of net metering programs by allowing solar systems to export during high-priced hours of the day.

Resilient on-site power is a key offering of the linear generator. The linear generator has black start capabilities, which allow it to isolate and operate during a grid shutdown or outage. This is instrumental in maintaining power quality and resiliency, especially for facilities with sensitive operations and critical infrastructure.

Renewables pairing is easy with the linear generator due to its load-following capabilities. It is equipped with proprietary technology that allows it to track load simply and without added cost or impact to efficiency, making it a perfect complement to intermittent renewable energy generation. With near-zero emissions, the linear generator is the bridge to a more complete sustainability program.

Mainspring logo
mainspring generator

Benefits of Mainspring

Fuel Agnostic

Runs on natural gas, propane or biogas

High efficiency

High expansion with direct conversion of linear motion into electricity

Low capital cost

Standard materials and manufacturing processes


Dispatchable power tracks onsite load and can easily pair with renewables

Near-zero emissions

Low-temperature reaction without a flame

Low maintenance cost

No oil, spark plugs, valves, or rotating bearings


Ensures continuous operation of isolated grids, reducing the need for backup generation

Get Started

Utility-scale performance in the size of a parking space

Easy Installation – One Fuel Connection – One Electrical Connection – One Data Connection
mainspring generator technical drawing

Each 250 kW package contains two linear generator cores, operating in tandem

Mainspring Features

220-250 kW, net AC
480 V, 3 Phase, 60 Hz
NOx < 2.5 ppmvd
Sound < 70 dBA @ 6 ft
Load Tracking
Zero to Full Power
Natural Gas or Biogas
8-25 psig Inlet
No Water
20.5’ x 8.5’ x 9.5’
UL 2200 Package
UL 1741 SA Inverters
Remote Monitoring

About Mainspring

Mainspring was founded in 2010 by three Stanford engineers seeking a new approach to generating clean, resilient, affordable electricity. Their research into high-efficiency methods of converting fuel to electricity led to the founding of the company and the development and prototype of their first linear generator. They also built a culture of collaboration and innovation.
Today Mainspring brings together a diverse, talented team of individuals who share the vision to address the growing threat of climate change and the need for affordable electricity for all. Our executive team brings deep expertise from leading clean energy companies and is backed by top-tier venture, strategic, and financial investors.

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