On April 30, 2026, the Wyoming Public Service Commission (WPSC) approved Rocky Mountain Power’s application to update its avoided cost methodology for qualifying facilities (QF) under Schedules 37 and 38. The WPSC adopted most of the Company’s proposal after the utility made significant changes based on testimony presented by the Renewable Energy Coalition (REC). The order in Docket No. 20000-687-ET-25 updates both the company’s standard and non-standard avoided cost tariffs.
Rocky Mountain Power, a subsidiary of PacifiCorp, request included two major changes. First, Rocky Mountain Power requested and received approval to use the locational marginal price (LMP) from Western Energy Imbalance Market (WEIM) nodal information for non-firm energy purchases. This issue was uncontested and follows the Federal Energy Regulatory Commission’s Order No. 872 in 2020, which allows utilities to use LMPs where appropriate.
Second, the WPSC approved revisions to Rocky Mountain Power’s Partial Displacement Differential Revenue Requirement (PDDRR) methodology for long-term avoided cost rates. The revised methodology incorporates updated proxy resource assumptions and allows for a temporary use of third-party ownership of proxy resources because Rocky Mountain Power is not considering ownership of new generating assets in the short term.
The updated avoided costs resulting from the PDDRR methodology were substantially influenced by the involvement of REC in the proceeding. First, REC proposed, and Rocky Mountain Power accepted, that wind and solar QFs be allowed to defer energy storage resources if wind and solar proxy resources were not included in the PDDRR inputs. Previously, wind and solar resources could only defer other wind and solar resources, respectively. Second, Rocky Mountain adjusted the allocation of the incremental cost of a displaced battery resource from 33 percent to 58 percent in the summer months for baseload QFs (hydro), consistent with the mix of summer and winter reliability events in the 2025 Integrated Resource Plan (IRP). Third, Rocky Mountain Power adjusted avoided cost rates based on changes to federal tax policy.
REC also advocated for Rocky Mountain Power to apply the entirety of fixed capacity costs of avoided proxy resources in the summer months for baseload resources to reflect the need for capacity resources in the summer months. Additionally, REC advocated that Rocky Mountain Power use the costs of a simple cycle combustion turbine as the proxy resource in years when a QF displaces Western Resource Adequacy Program (WRAP)-compliant market purchases. The Commission ultimately rejected these proposals.
The new avoided cost rates became effective April 30, 2026. Sanger Greene PC (Irion Sanger and Diego Rivas) represented and assisted REC in the proceeding.