Cascadia Ridge BESS: Community Research
Jupiter Power LLC wants to build a 130 MW battery storage facility on about 50 acres across six parcels in unincorporated King County, on Snoqualmie Ridge. It would connect to PSE’s Mt. Si substation via a 115kV tie-line.
We support Washington’s clean energy goals and the need for grid storage. But this site has serious problems that a SEPA checklist cannot answer: a constrained valley where temperature inversions trap toxic emissions, thousands of homes and a school nearby with limited evacuation routes, a fire district that cannot confirm preparedness, seismic hazards, and dozens of private wells. We are asking King County to require a full Environmental Impact Statement before permitting this project. Here’s why.
Key facts
Site. Adjacent to thousands of homes on Snoqualmie Ridge. Cascade View Elementary is half a mile away. Fisher Creek (salmon habitat) runs through the parcel. Ridge-bounded valley where temperature inversions trap emissions close to the ground. Dozens of private wells downhill. Site details.
Fire and toxic emissions. Battery fires can produce hydrogen fluoride, a gas that is immediately dangerous to life at 30 ppm. No atmospheric dispersion modeling has been done for this site. Eastside Fire & Rescue has stated it “cannot confirm” preparedness for an incident of this type and scale. EPRI failure rate data puts the 30-year probability for a facility this size between 9% and 70%.
Seismic hazard. The Southern Whidbey Island Fault is mapped through the valley. USGS puts the 50-year probability of a M6.5+ earthquake in the Puget Sound at 85%. Nobody has modeled the chain from earthquake through thermal runaway to contaminated runoff into Fisher Creek. Full analysis.
Governance. The site is in unincorporated King County. The City of Snoqualmie has no jurisdiction, even though Snoqualmie Ridge residents are the most affected. BESS is a permitted use under the site’s UR zoning, with no public hearing required. PSE’s own siting study screened out Mt. Si. Permitting details.
What the records show. King County Department of Local Services released 730 MB of Jupiter Power’s permit application and related communications on April 13, 2026. The civil plans point to a 410 MW / 1,640 MWh facility, not the 130 MW public headline. The sound study predicts zero compliance margin at the closest home. The application grades 28.3 acres on a forested site with zero existing impervious surface. Every fire-safety study is deferred to late 2026. Read the findings.
Where things stand
No active permit application as of March 2026. Jupiter Power filed a Commercial Site Development permit in December 2025 and canceled it in February 2026. Jupiter Power held a voluntary community open house on March 17 that drew a standing-room-only crowd. There is no community meeting requirement in King County’s BESS ordinance. SEPA review is the only formal public input opportunity.