Commission hears concerns about WRAP, seams and transmission as Markets Plus application advances

Public Service Company of Colorado's witnesses told the Colorado Public Utilities Commission that participation in SPP Markets Plus will require the company to participate in the Western Resource Adequacy Program (WRAP) and that participation raises planning, operational and transmission questions the company has not fully quantified.

Why it matters: WRAP participation affects how the company shows forward resource adequacy, how capacity gets accredited (ELCC, PRM methods), and whether additional transmission will be needed to satisfy forward showings. Parties asked whether Markets Plus will help or complicate coordination with other proposed market constructs (for example, SPP RTO expansion and EDAM). The commission's rule language (discussed in testimony as rule 37-53(a) and related sections) requires parties to show plans to optimize dispatch and unit commitment where multiple regional markets would operate.

What witnesses said

- WRAP onboarding: Taylor said Markets Plus participants must join the Western Resource Adequacy Program and that Public Service does not currently participate in wrap. He stated the company would be a member by the Markets Plus go-live date and described limited recent company engagement with WRAP design work (company participated earlier but not currently a WRAP committee member).

- Accreditation and PRM: Taylor told commissioners that WRAP uses ELCC, LOLE and planning reserve margin calculations and that those methods differ from the company's current resource plan assumptions; he said WRAP's recent PRMs appear lower than Public Service's planning reserve margins and that the company has not fully analyzed what those differences imply for the ERP forward showing requirements.

- Transmission and seams: Taylor and other witnesses described a set of operational tools intended to reduce 'seams' friction between Markets Plus and adjacent constructs: real-time dispatchable transactions (RTDT), Area Control Error diversity interchange (ADI), and a Markets Plus seams roadmap (executive summary approved by the Market Plus executive committee). The company said RTDT is due to be implemented by April 2026, and that RTDT and ADI would be usable regardless of Markets Plus participation, but the witnesses said full market-to-market optimization (day-ahead unit-commit coordination) is an open design workstream and could take years.

- Export capability and modeling adjustments: Intervenors challenged the company's production-cost study assumptions about export capability. The company testified that WEMG/E3 results originally overstated exports; the company used a stepwise correction (an APP-4 scenario with a 900 MW cap, then a further technical transfer-capability assessment that yielded a 478-MW figure) and then applied that scaling to production-cost and greenhouse-gas estimates. Witnesses acknowledged the transfer-capacity estimates depend on internal rights and Tri-State/other parties' arrangements and that export capability to non-Markets Plus areas is constrained (company used a 30-MW proxy for average exports outside its balancing area in some parts of the record).

What the commission and intervenors asked

Intervenors asked for clearer, updated WRAP-onboarding schedules, asked whether the company has updated PRM and ELCC studies to include company data, pushed for transmission planning details (projects, timelines, costs), and requested more granular export/import capability modeling. Witnesses agreed those are open items.

Ending: Parties and the commission agreed these operational and transmission issues need continued attention. The company was asked to provide follow-up materials and to coordinate with Markets Plus stakeholders and the WRAP implementation process; commission policy questions about how to ensure seams optimization and resource-accreditation compliance will be a part of the further record.