SnoPUD: Arlington Microgrid Project

Snohomish County PUDSource:  Snohomish County PUD website, August 2018.

The Arlington Microgrid and Clean Energy Technology Center project represents a new technology and approach that offers grid resiliency and renewable energy integration. The project will include a 500-kilowatt solar array with smart inverters, a 1,000 kW/1,000 kWh lithium-ion battery storage system and several vehicle-to-grid charging stations for use with the PUD’s electric fleet vehicles.

What’s a “microgrid”?

In simplest terms, a microgrid offers a unique emergency backup system for power. It is comprised of locally grouped electricity sources that can feed the main electrical grid but can also be disconnected to serve a specific location.

Arlington Microgrid

The Arlington Microgrid is a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. In an emergency, the microgrid would disconnect from the main grid and help power the PUD’s new local office in Arlington.

As part of the microgrid, the PUD is planning a Community Solar program at the site. Community Solar programs make it easier for all customers to benefit from solar energy by leasing or purchasing shares at a community site without needing a sunny roof or funding for their own solar panels.

The Arlington Microgrid will focus on disaster recovery and grid resiliency. The system will be designed and sized to provide power to the Arlington Local Office during an outage that could be caused by a wind storm or by the big Cascadia Rising type earthquake that has been in the news recently. When the Microgrid isn’t acting like a giant solar-powered emergency generator, it will be helping to pay for itself by providing renewable energy integration and grid support. Additionally, with the growing interest in electric vehicles, the microgrid will incorporate a few electric fleet vehicle charging stations referred to as Vehicle-to-Grid or V2G. A V2G charging station can charge the car as well as allow for the energy stored in the electric vehicle to flow back to the grid and provide support during an outage.

“If the grid were to go down in a disaster, this building and facility would play a very important part of the PUD’s response,” said Scott Gibson, project manager. “This will be the only sustainably powered facility in the entire service territory and would give us a huge advantage. The worst-case scenario is that a disaster might leave the grid along with the transportation infrastructure damaged for several months. The Arlington Microgrid could sustain the local office in the meantime. Also, its proximity to the Arlington Airport would be key in an emergency.”

The project also features a facility – the Clean Energy Technology Center – that will be used to demonstrate the microgrid technology and help educate the public about burgeoning technologies in the energy world.


  • Received $3.5 million in funding from the Washington Clean Energy Fund
  • Total project cost: $12 million
  • Timeline: 2017-2020
  • Elements include battery energy storage, solar array, microgrid controller, and Clean Energy & Technology Center

Other projects receiving funding from the Washington Clean Energy Fund include Avista Spokane Micro-Transactive Grid ($3.5 M), Energy Northwest – Richland Solar Energy Storage ($3 M), Seattle City Light Solar Microgrid ($1.5 M), and OPALCO Solar Energy Storage ($1 M).