The proposed Cascade Solar Project would feature a 300-megawatt solar energy facility alongside a 300-megawatt battery energy storage system, making it a substantial addition to the region’s growing renewable energy industry.
The development, proposed by Sawtooth DevCo LLC, would encompass approximately 1,674 acres of land in rural Grant County, including ground-mounted solar panels, a battery storage facility, electrical substations, maintenance buildings and supporting infrastructure.
According to the Washington Department of Ecology’s environmental review filing, the application was formally issued for public review Monday, November 9, with residents given until November 24 to submit comments on potential environmental impacts.
One of the most significant considerations surrounding the proposal involves its potential impact on the region’s shrubsteppe habitat.
According to the project’s environmental checklist, approximately 868 acres of the proposed buildable area are classified as shrubsteppe habitat.
Environmental surveys conducted in 2025 and 2026 identified areas of native sagebrush vegetation, grasslands and previously disturbed agricultural land.
The developer’s environmental assessment states that development would avoid existing sagebrush habitat where possible, while disturbed areas would be reseeded with native grasses and other vegetation following construction.
The assessment also identified a population of dark-spine ball cactus, a plant considered rare in Washington, near the northern edge of the proposed development. The developer states that the plants are located in an area excluded from construction.
Wildlife surveys documented an active red-tailed hawk nest, a raven nest and mule deer moving through the broader study area.
Although the surveys did not identify threatened or endangered species occupying the project site, the environmental review acknowledges that the surrounding landscape provides potential habitat for several sensitive species.
The developer has submitted a habitat management plan intended to address environmental impacts in consultation with Grant County and the Washington Department of Fish and Wildlife.
Under the proposal, electricity generated by the solar panels would be delivered to the regional electrical grid through an interconnection with an existing Grant County Public Utility District transmission line.
The project would also include a large lithium-ion battery storage system designed to store electricity for later delivery.
Unlike solar panels, which generate electricity when sunlight is available, battery storage systems can retain energy and release it when needed, potentially allowing the facility to provide power during periods of reduced sunlight.
The proposed battery system has a power capacity of 300 megawatts, although the documents reviewed do not establish how many hours it could operate at that output.
Planning materials indicate that the development would occupy both private property and land managed by the Washington Department of Natural Resources.
The project’s emergency response plan identifies approximately 1,546 acres of private land and 128 acres of state-managed property within the proposed development area.
According to the environmental checklist, construction activities are expected to last approximately 12 to 24 months, depending on the phase of development.
Construction would include grading, installation of solar arrays, electrical infrastructure and battery storage equipment.
Project documents anticipate fewer than 100 vehicle trips daily during construction, including heavy-duty trucks, equipment deliveries and employee vehicles.
Construction traffic would primarily use State Route 28 and nearby county roads.
Once completed, the facility would operate continuously with remote monitoring. The developer anticipates approximately one or two operations and maintenance employees supporting the site.
The battery storage system would include monitoring equipment intended to detect overheating and other potential safety hazards.
The developer has also prepared an emergency response plan addressing fires, electrical emergencies and coordination with local emergency responders.
Grant County received the conditional use permit application and environmental checklist September 29 and determined the submissions were procedurally complete October 29.
Because the project is proposed within an area zoned Rural Resource, it requires county land-use review and approval before construction can proceed.
County planning officials have indicated they anticipate issuing a mitigated determination of nonsignificance following environmental review. Such a determination would mean potentially significant environmental impacts could be addressed through mitigation measures rather than requiring a full environmental impact statement.
However, that determination has not yet been finalized.
Additional reviews include habitat protection, cultural resources, visual impacts, drainage, geotechnical conditions and eventual decommissioning of the facility.
A public hearing date has not yet been established.
Residents wishing to comment on the project must submit their remarks by 5 p.m. Tuesday, November 24, 2026.
Comments may be directed to Grant County planner Michelle Mercer at mmercer@grantcountywa.gov or by calling 509-754-2011, extension 2595.
Application materials are available through the Grant County Renewable Energy Projects webpage.
The proposed Cascade Solar Project remains under review, and construction cannot begin until the necessary approvals and permits have been secured.
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