FAQ

What is a BESS?

A Battery Energy Storage System (BESS) is a facility that stores electricity in large banks of batteries and releases it back to the grid when needed. The proposed Cascadia Ridge facility would be 130 MW / 520 MWh, enough to power roughly 100,000 homes for four hours. In practice, it’s rows of battery modules in prefabricated enclosures, plus inverters (to convert DC to AC), transformers (to step up voltage), cooling systems, fire suppression equipment, and switchgear connecting to the transmission grid. This project would connect to PSE’s existing Mt. Si substation via a 115kV tie-line.

Why is PSE interested in having a BESS?

Washington’s Clean Energy Transformation Act (CETA) requires utilities to be greenhouse gas neutral by 2030 and supply 100% clean electricity by 2045. Wind and solar don’t generate power on demand. They produce when conditions are right, not necessarily when people need electricity. Storage bridges that gap: charge when renewables are overproducing, discharge during peak demand. Without storage, PSE either overbuilds generation (expensive for ratepayers) or keeps fossil fuel peakers running (which violates CETA). PSE’s Mt. Si substation sits adjacent to the proposed site, making it a logical interconnection point.

Why not build it somewhere away from residential areas?

Storage needs to be near where power is consumed, not where it’s generated. You can’t put a battery next to a wind farm in Eastern Washington and expect it to help the Eastside during peak demand without expensive new transmission lines. Transmitting stored power long distances means energy losses both ways, and building new long-distance transmission is slow to permit and faces its own opposition.

PSE’s Mt. Si substation sits right next to this site. It’s an existing grid interconnection point where PSE needs capacity. The electrical interconnection makes sense. But PSE’s own siting study screened out Mt. Si on electrical criteria. The study also included “Good Neighbor” criteria that flagged residential areas, schools, and hospitals as making a location less desirable, which describes exactly the conditions that exist here.

That’s the core problem. The grid connection is real, but so are the siting constraints: a constrained valley where temperature inversions trap emissions, proximity to schools and thousands of homes, seismic hazards, limited evacuation routes, a fire district that cannot confirm preparedness, and dozens of private wells downhill of the site. These are questions a full Environmental Impact Statement is designed to answer, and a SEPA checklist is not.

What are the concerns?

The site raises questions across toxic gas dispersion, school proximity, emergency response, seismic hazard, groundwater, noise, and land use compatibility. The common thread is that none of these have been adequately studied for this location. See What We’re Asking for the full list and the evidence behind each one.

Who will decide whether the proposed BESS project will be approved?

King County. The site is in unincorporated King County, so the City of Snoqualmie has no permitting authority even though Snoqualmie Valley residents are the most directly affected. BESS is a permitted use under the site’s UR zoning. No public hearing is required. The main avenue for public input is the 14-day SEPA comment period that opens when Jupiter Power files a new permit application. See permitting for the full regulatory framework and how to write a SEPA comment to prepare.

What happens to a lithium-ion BESS in an earthquake?

The Snoqualmie Valley is exposed to three independent earthquake sources, including the Southern Whidbey Island Fault mapped through the valley. Lab testing shows lithium-ion cells can develop internal short circuits from small mechanical deformations. King County’s ordinance requires IEEE 693 seismic qualification, which keeps equipment on its mounts, but nobody has tested whether utility-scale BESS enclosures protect cells during seismic shaking. No utility-scale BESS has been tested by a major earthquake. See the earthquake risk section of our fire risk analysis.

If lithium-ion batteries are sensitive to vibration, why are they safe in cars and planes?

Different kind of stress. Driving and flying produce low-amplitude, high-frequency vibration. EV and aircraft battery packs are purpose-built for that: cells are locked into rigid, crash-tested enclosures with vibration isolation and per-cell monitoring. The cells don’t move relative to each other.

Earthquake shaking is the opposite: high-amplitude, low-frequency. It’s more like a car crash than road vibration. And lithium-ion EV crashes do cause fires. That’s well documented.

The packaging matters too. An EV battery is a sealed, crash-engineered unit. A utility-scale BESS is rack-mounted modules in shipping containers, designed for stationary use. IEEE 693 keeps the racks on their mounts, but the cell-level containment inside the modules isn’t crash-tested the way an EV pack is. Nobody has tested whether utility-scale BESS enclosures protect cells during seismic shaking the way an EV pack protects them during a crash.

Getting the facts right

Our community’s opposition is strongest when it’s accurate. Some claims circulating in public comment and social media need correction. The real facts are alarming enough.

McMicken, Arizona (2019): firefighters were injured, not killed

Four firefighters were hospitalized (one critically) when an unvented battery container exploded at the McMicken BESS facility in Surprise, Arizona. None died. The explosion occurred when first responders opened the container door and flammable gas that had accumulated inside ignited. The real lesson is about deflagration venting and gas accumulation, and Jupiter Power has not disclosed their venting design for Cascadia Ridge. That’s worth raising. But claiming firefighters died weakens the argument when someone checks.

Moss Landing evacuation: 1,200-1,500 people, not 15,000

The January 2025 Moss Landing fire evacuated approximately 1,200 to 1,500 people. The larger number may reflect the broader area population, but it wasn’t the evacuation count. The accurate comparison is actually worse for us: Moss Landing is a smaller community with more ways out, and the evacuation still took over 25 hours. Snoqualmie Ridge is bigger, has two primary egress routes, and demonstrated gridlock during the December 2025 floods. The real numbers make the case.

Monitoring: automated systems exist, but the gaps are real

BESS facilities have continuous automated monitoring through battery management systems (BMS) that track temperature, voltage, and state of charge around the clock. Saying “there is no monitoring” is easy to rebut and makes the community look uninformed.

The real gap is different and worth pressing on: there is no requirement for permanent fenceline air quality monitoring at BESS facilities. At Moss Landing, EPA deployed monitoring stations reactively, after the fire started. There is also no requirement for soil or water monitoring near adjacent waterways. And “monitoring” through a BMS is not the same as having trained personnel on site. Jupiter Power has indicated the facility would not be permanently staffed. These are the questions that matter, and they don’t require exaggeration to be alarming.

Failure rates: use the range, not just the high number

EPRI data supports two failure rate metrics. The per-project rate (0.3%/year, treating all facilities equally regardless of size) yields a 30-year probability of about 9%. The per-GW rate (0.2-0.3 failures/GW/year, adjusted for the 130 MW capacity) yields about 70%. The actual risk is somewhere in that range. Citing only the 45% number without context invites a rebuttal that discredits the entire argument. Presenting both numbers and explaining the difference is more persuasive and harder to dismiss. See fire risk for the full analysis.

What can I do?

See Take Action for specific steps: who to contact, what to ask for, and how to make your voice heard.