Rocky Mountain Power said the 2025 IRP reflects a downward trend in using market purchases for capacity and that expected changes under the Western Resource Adequacy program (WRAP) and entry to an enhanced day‑ahead market (EDAM) will require more physical resources rather than relying on short‑term market capacity.

Dan McPhail told the technical conference that market capacity purchases — often called front‑office transactions — are expected to become harder to count as capacity under WRAP by 2028, and that EDAM participation requires a day‑ahead balancing showing. He said the IRP therefore reduced modeled reliance on market purchases in the 2028 time frame and incorporated restrictions on when market purchases can be used in high‑risk hours.

The company explained procedural differences between Schedule 37 and Schedule 38: Schedule 37 excludes unsigned QFs and uses smaller proxy sizes (10 MW examples), while Schedule 38 treats signed contracts differently and the proxy starting points and megawatt assumptions differ (company cited an 80‑MW Schedule 38 proxy in recent analyses). Rocky Mountain Power illustrated how changes in queue activity (Schedule 38 QFs) and signed contracts moved avoided‑cost prices up and down across filings.

Separately, the company identified an error found after the IRP filing that misaligned dollar year and technology year escalation rates in proxy resource cost inputs. McPhail said the correction would "lower wind costs a smidge" in 2028 and raise solar proxy costs a bit in 2032 because of a real/nominal mix‑up with the NREL Annual Technology Baseline inputs. The company said the changes are modest and will be corrected in the final workpapers.