Decatur Island Battery Energy Storage System

Decatur Island Aerial

Decatur Island Battery Energy Storage System

Battery Energy Storage Pairs with Solar Energy to Bring Independence and Reliability to a Remote Archipelago

An ocean lies between the San Juan Islands and the main source of its power. The archipelago’s energy supply comes from hydropower generated in mainland Washington and Oregon, transmitted by aging submarine cables that cross the Salish Sea to serve 20 islands. Orcas Power & Light Cooperative brought us on board as owner’s engineer to sustainably extend the life of those cables and add reliability to the islands’ grid using battery energy storage.  

Residents and tourists are drawn to the islands by the remote, rugged beauty and pristine environment. OPALCO is working to establish a baseline of energy independence using clean, renewable energy. Building upon a community solar project on Decatur Island, the battery storage project is designed with three main benefits for OPALCO’s members: 

  • Extending the life of the submarine cable by three years: The battery will charge when power demand is low, and discharge when demand is high, reducing the cable’s maximum load. 
  • Saving money for members: Peak load — the most expensive power — from the submarine cable will be reduced. 
  • Building independence and grid reliability: Intermittent energy generated from the solar array will be stored and dispatched using a more controlled, strategic system. Using lithium ion batteries, the project is designed to supply four hours of backup power during an outage. 

Battery energy storage paired with community solar is a solution OPALCO intends to replicate as a model for future micro grids across the archipelago.  

The project is partially funded by a $1 million grid modernization grant awarded to OPALCO as part of Washington Clean Energy Fund II, a program to support clean energy projects in the state.  


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Recognized by Fast Company's World Changing Ideas Awards. Honorable mention in the Energy Category.

Decatur Island Aerial
Orcas Power & Light Cooperative

Decatur Island, WA
United States


World Changing Ideas Honorable Mention (2020)
Energy Category
Fast Company