Mapping shows about 11,600 acres potentially eligible for solar under current draft setbacks

The Whitman County Planning Commission got its first countywide illustration of how proposed setback and siting rules would affect solar and battery-energy-storage siting at its June 17 workshop.

Rachel, the consultant who led the mapping exercise, told commissioners the analysis applied the draft dimensional standards as visual filters and produced a new eligible-parcel area of about "11,623 acres." She said the map layered a 130-foot centerline buffer to represent a roughly 100-foot setback from right-of-way, a 7-mile radius around key parks, a 2-mile buffer for transmission-line proximity and a 1,500-foot setback from nonparticipating structures.

"The new eligible parcel area is 11,623 acres," Rachel said during her presentation. She cautioned the visualization was a desktop exercise meant to illustrate the effects of policy choices, not to substitute for parcel-level review.

Staff and commissioners stressed the mapping omitted several site-level constraints. "We did not take a look at critical areas — steep slopes and wetlands — parcel size or cultural resources," Rachel said, noting those filters would likely further reduce the acreage shown on the map.

Commissioners said the visualization was useful but emphasized it was conservative in places: the 1,500-foot buffer was modeled assuming all adjacent properties would be nonparticipating, and the mapping measured some distances to structures rather than property lines. Several commissioners also said proximity to transmission infrastructure is a primary limiting factor for where large solar projects realistically locate.

Next steps outlined by staff include refining language in the draft ordinance to match mapping assumptions, clarifying whether setbacks measure to occupied buildings or to property lines, and preserving conditional-use and SEPA processes for site-level environmental review.