PG&E pilots new ‘linear generator’ in Napa microgrid

The linear generator utilising natural gas and directed renewable biogas is designed to displace diesel in mobile generation applications.

The pilot by Pacific Gas & Electric, the first utility deployment of the new technology from clean energy generation developer Mainspring Energy, is aimed to demonstrate its potential to reduce diesel and emissions during emergencies and power shutoffs.

The installation at the Angwin distribution microgrid site in Napa County is part of PG&E’s commitment to implementing cleaner energy solutions to deliver replacement power during events such as winter storms or earthquakes.

In the pilot, which follows a rigorous testing programme, the linear generator will be paired with the onsite diesel generator to ensure that service remains reliable for the Angwin community.

Have you read?
Pacific Gas & Electric replaces poles and wires with remote microgrid
PG&E files $7.4bn clean energy and grid resilience plan

“We are excited to explore new technologies like the linear generator to help keep customers powered during larger outages while also reducing the use of diesel backup generation,” says Jason Glickman, Executive Vice President, Engineering, Planning & Strategy at PG&E.

“This is a low emissions, resilient, and affordable alternative that holds a lot of promise for our future.”

Currently the company deploys mobile diesel generators connected to the grid at substations, distribution microgrid sites, community resource centres and other critical facilities as they are needed and available.

Mainspring Energy’s 240kW linear generator, about the size of a parking space, uses a low temperature reaction of air and fuel to drive magnets through copper coils to produce electricity, i.e. the conversion results from motion along a straight line, as distinct from an engine or microturbine.

A unique characteristic of the technology, which was launched in March, is that it can ramp up and down quickly to meet power load demands at a fraction of the emissions of reciprocating engine technologies.

The Angwin deployment is being financed by clean energy solution provider NextEra Energy Resources, which delivers a portfolio of nearly 1,000MW of wind, solar and now linear generation to PG&E.

For the deployment, the linear generator is connected to both PG&E’s electric distribution system and its natural gas distribution system. NextEra Energy Resources is injecting biogas fuel purchased from another location into the gas system to offset the linear generator’s usage of natural gas.