How to Write a SEPA Comment

When Jupiter Power files a new permit application with King County, the State Environmental Policy Act (SEPA) requires an environmental review. King County publishes a Notice of Application and opens a 14-day public comment window. At the close of that window, King County issues a threshold determination (DNS, MDNS, or DS). There is no public hearing and no further comment period after the determination – if King County issues a DNS over the community’s objections, the only recourse is a court appeal. This is the primary formal opportunity for public input on this project. If you want your concerns on the record, this is the moment.

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What SEPA does

SEPA (RCW 43.21C) requires government agencies to consider environmental impacts before approving projects. The developer submits an Environmental Checklist. King County reviews it and issues a threshold determination:

• Determination of Non-Significance (DNS): King County finds no significant adverse impacts. The project moves forward.
• Mitigated DNS (MDNS): King County finds impacts can be addressed with permit conditions (noise limits, monitoring, setback adjustments, etc.).
• Determination of Significance (DS): King County finds the project may cause significant adverse impacts. This triggers a full Environmental Impact Statement (EIS), a detailed independent study of all environmental impacts and alternatives, with additional public comment periods.

Public comments submitted during the 14-day window go directly to the responsible official and inform the threshold determination. A well-documented comment showing significant impacts can push King County toward a DS instead of a DNS. The responsible official must consider every substantive comment received.

No BESS project in Washington has ever been required to complete a full EIS. Every project that reached a threshold determination was approved. But the conditions attached to those approvals varied dramatically based on the quality of public comments. See what happened at other Washington BESS projects.

What a good outcome looks like

This site has problems that go beyond battery chemistry. The constrained valley topography traps emissions under temperature inversions. Cascade View Elementary is half a mile away, with school bus routes within 500 feet. Eastside Fire & Rescue cannot confirm preparedness. The city’s evacuation plan does not address an industrial toxic release. The Southern Whidbey Island Fault is mapped through the valley. Dozens of private wells surround the site. PSE’s own siting study screened out Mt. Si on the merits. These are questions a checklist cannot credibly evaluate.

Determination of Significance (DS) / full EIS. This is what we are asking for. A DS triggers a full Environmental Impact Statement, which requires:

• A formal alternatives analysis covering alternative technologies, alternative sites, and the no-action alternative
• Independent analysis of fire risk, toxic emissions, noise, stormwater, habitat, seismic hazard, and cumulative effects
• Atmospheric dispersion modeling for toxic gases under valley inversion conditions
• Additional public comment periods (scoping, and 30 days for the draft EIS)
• Disclosure of information Jupiter Power has not provided: setback distances, fire suppression design, emergency response plan, decommissioning plan, and noise study results

A full EIS does not kill the project. It forces the questions to be answered before the project is approved, not after. If the project can demonstrate that it operates safely at this location, the EIS will show that. If it cannot, the community deserves to know before a permit is issued.

A DNS with no meaningful conditions, or an MDNS that does not address the site-specific risks identified above, is the outcome the SEPA comments are designed to prevent.

The legal standard

Under WAC 197-11-330, “significant” means “a reasonable likelihood of more than a moderate adverse impact on environmental quality.” The responsible official considers several factors:

• (a) Site-specific context. The same project may have a significant impact in one location but not another. A 130 MW BESS on open land miles from homes is different from one adjacent to the City of Snoqualmie (population 14,550 per the Washington State Office of Financial Management’s April 1, 2025 official estimate), with homes backing up to the site boundary, fish-bearing streams connected to a salmon-bearing watershed, and a valley prone to atmospheric inversions.
• (b) Absolute effects. The quantitative scale of impacts matters regardless of the existing environment.
• (c) Cumulative impacts. Several individually marginal impacts, considered together, may add up to a significant impact.
• (d) Uncertainty. Where impacts cannot be forecast with precision because variables cannot be predicted or quantified, that uncertainty itself weighs toward a finding of significance.

Factor (d) is important here. Jupiter Power has not committed to a battery chemistry (stating it is “expected to be lithium ion (LFP) or sodium ion”), has not disclosed the fire suppression system type, the emergency response plan, or the atmospheric dispersion characteristics at this site. When the developer hasn’t provided enough information to evaluate impacts, the responsible official cannot responsibly issue a DNS.

What makes a comment effective

The responsible official is required to consider your comment, but it needs to give them something to work with. Here is what separates a comment that influences the decision from one that gets filed and forgotten.

Be specific about the environmental impact. “I’m concerned about safety” is not actionable. “Lithium-ion thermal runaway produces hydrogen fluoride gas at concentrations exceeding the NIOSH IDLH of 30 ppm; no atmospheric dispersion modeling has been conducted for this site under the valley inversion conditions documented by the Puget Sound Clean Air Agency” gives the official a specific impact they must address.

Reference the SEPA checklist element. The Environmental Checklist (WAC 197-11-960, Section B) is organized into categories. Tying your comment to a specific element makes it harder to dismiss. The relevant elements for this project are listed below.

Cite evidence. Published studies, government data, comparable incidents, and professional expertise all strengthen your comment. If you’re a credentialed professional (physician, engineer, geologist, ecologist), say so.

Ask for specific studies or disclosures. Don’t just say the impact is bad. Ask King County to require the developer to produce specific information: a site-specific seismic hazard assessment, atmospheric dispersion modeling for HF under inversion conditions, a noise study demonstrating compliance with K.C.C. 12.86, a hydrogeologic assessment for groundwater impacts, an alternatives analysis covering battery chemistry and alternative sites.

Explain why mitigation is insufficient. If you’re arguing against a Mitigated DNS, explain why permit conditions can’t adequately address the risk. For example: you can mitigate noise with a wall, but you cannot mitigate a hydrogen fluoride plume from a lithium-ion thermal runaway event with any proven technology at this scale.

SEPA checklist elements relevant to this project

These are the categories in the Environmental Checklist where this project has probable adverse impacts. You don’t need to cover all of them. One well-supported comment on a single element is more valuable than a vague comment touching everything.

B.1 Earth

Seismic hazard. The Snoqualmie Valley is exposed to three independent earthquake sources. USGS Fact Sheet 2025-3050 puts the 50-year probability of a M6.5+ earthquake in the Puget Sound at 85% (deep) and 17% (crustal). The Southern Whidbey Island Fault is mapped through the valley. No site-specific seismic hazard assessment has been submitted, and no study exists on utility-scale BESS performance during seismic events. See our seismic hazard analysis.

B.2 Air

Hydrogen fluoride emissions from lithium-ion thermal runaway. Larsson et al. (2017) measured 20-200 mg of HF per Wh of battery capacity across 39 fire tests. HF is immediately dangerous to life and health at 30 ppm (NIOSH IDLH). No atmospheric dispersion modeling has been conducted for this site under valley inversion conditions. See our fire risk analysis.

B.3 Water

Fisher Creek (Type F, fish-bearing) runs through the northwest portion of the primary parcel. Contaminated fire suppression runoff (heavy metals, fluoride compounds) would drain directly into the creek and from there into the Snoqualmie River watershed. See our site and environment analysis.

B.4 Plants / B.5 Animals

ESA-listed Chinook salmon (threatened, 1999), steelhead (threatened, 2007), and bull trout (threatened, 1999) are present in the Snoqualmie River downstream of Fisher Creek. The Critical Areas Designation identified potential Vaux’s swift nesting habitat and western toad on the site.

B.7 Environmental health

Toxic gas exposure risk to the Snoqualmie Valley population (15,000+). Hospital preparedness: Snoqualmie Valley Hospital is approximately 1.2 miles from the site and is a critical access hospital without HazMat capability. Evacuation capacity: the City of Snoqualmie’s ESF #16 plan does not contemplate an industrial toxic release.

B.8 Land use

The site is in the City of Snoqualmie’s Southwest Potential Annexation Area. The city’s Comprehensive Plan designates this land for “master-planned business park” and “innovative mixed use.” King County’s UR zoning allows BESS as a permitted use, but the SEPA checklist asks whether the proposal is consistent with existing land use plans.

Property value impacts as evidence of land use incompatibility. No peer-reviewed study has examined property values near BESS facilities (the industry is too young), but three studies of analogous energy infrastructure show consistent declines: Davis (2011) found 3-7% decline within 2 miles of new power plants using Census microdata across 92 plant openings; Hu et al. (2025, PNAS) found 4.8% average decline within 3 miles of visible solar installations (8.3 million transactions, 3,699 sites), increasing to ~7% within 0.5 miles; Elmallah, Hoen et al. (2023, LBNL) found 1.5% decline within 0.5 miles across 1.8 million transactions near 1,500+ solar sites. Property value decline is not itself a SEPA impact, but the environmental factors that cause it (noise, visual incompatibility, perceived safety risk, land use conflict) are squarely within SEPA’s scope under WAC 197-11-444 (“built environment”). Snoqualmie Ridge has approximately 3,000 homes within 2 miles. King County’s BESS ordinance (Ordinance 19824, Condition 29) separately requires an alternatives analysis covering “social and economic impacts,” which provides an additional hook for requiring a property value impact assessment.

B.14 Transportation

Evacuation route capacity during a toxic release. The Snoqualmie Valley has limited evacuation routes, and Snoqualmie Ridge (the closest residential area) has two primary options: Snoqualmie Parkway and SR-18. Construction traffic impacts on residential streets.

B.15 Public services

Fire district capacity: King County Fire Protection District No. 38. No tabletop exercise has been conducted. No mutual aid agreements have been disclosed. The district would need specialized HazMat capability it may not currently have.

What to include in your comment

1. Your name and address (establishes standing as an affected resident)
2. The project name and permit number (when available)
3. The specific SEPA checklist element(s) you’re addressing
4. The probable adverse impact, stated with as much specificity as you can
5. Evidence supporting your concern (data, studies, professional credentials)
6. What you’re asking King County to require (specific study, analysis, or disclosure)
7. Your request: a Determination of Significance and full Environmental Impact Statement

What NOT to do

• Don’t submit form letters. Ten identical comments count as one. Write in your own words, even if they’re brief.
• Don’t make claims you can’t support. Our community’s position is strongest when it’s accurate. See our fact-check section for claims that need correction.
• Don’t undermine the case for grid storage. Battery storage is essential infrastructure. Solar is the cheapest available generation source, but it only produces power when the sun is shining. Storage makes it available on demand, when people actually need it. Without storage, PSE either overbuilds generation at ratepayer expense or keeps fossil fuel peakers running in violation of Washington’s clean energy law. The argument that works in SEPA is not “no BESS anywhere” but “this site has specific, unaddressed environmental risks that require a full EIS before a permit is issued.” The comments most likely to influence King County’s threshold determination are the ones that identify specific probable impacts the Environmental Checklist fails to address.
• Don’t send your comment before the window opens. Comments submitted outside the official comment period are not part of the administrative record. Wait for our alert.

When you’re ready

Sign up for updates. We’ll email you the day the comment window opens with the submission address and deadline. If you want to start drafting now, pick one checklist element above where you have knowledge or experience, and write about that. Short and specific beats long and vague.

If you’re a credentialed professional (physician, engineer, geologist, ecologist, financial analyst) and want to coordinate on technical comments, contact us.