## Facts

- Rocky Mountain Power (RMP), a division of PacifiCorp, was a public utility providing electric service in Wyoming.
- RMP filed an integrated resource plan (IRP) with the Wyoming Public Service Commission (the Commission) every two years, describing the generation and transmission resources RMP expected to provide in Wyoming.
- In April 2018, the Oregon Public Utility Commission ordered PacifiCorp to perform a limited coal-system-optimization study of PacifiCorp’s coal-fired generation units (the coal study).
- The coal study concluded that 16 coal-fired units should be closed.
- On October 18, 2019, RMP filed an IRP that incorporated proposals and assumptions about early retirement of coal-fired resources based on the coal study.
- The IRP proposed replacing 4,500 megawatts of coal-fired power generation in Wyoming with a portfolio that included 6,300 megawatts of solar resources, 4,600 megawatts of new wind resources, 2,800 megawatts of battery storage, and increased energy-efficiency resources.
- Given the coal study’s role in the IRP and the scale of the proposed change in resource mix, the Commission initiated an investigation of the coal study and the IRP under Wyoming Stat. § 37-2-117.
- Commission staff identified deficiencies in the IRP, including that it did not fully analyze (1) whether negative impacts to Wyoming communities from premature coal-unit retirements outweighed the claimed benefits of the proposed portfolio, (2) the basis for carbon-cost assumptions used to estimate future coal-unit operating costs, and (3) carbon-capture technologies as a potential alternative to early retirements.
- The Commission received testimony from local-government witnesses regarding significant negative social and economic effects that premature coal-plant closures could have on workers and communities, including related impacts on local revenues and public services.
- The Commission also heard testimony that RMP had not proposed an adequate way to mitigate the anticipated economic losses associated with early retirements.
- Following the investigation, the Commission issued a report addressing the IRP and the coal study.

## Issues

1. Whether the Wyoming Public Service Commission could initiate an investigation under Wyoming Stat. § 37-2-117 into the assumptions and analysis supporting Rocky Mountain Power’s October 18, 2019 IRP, including the coal study relied on for early coal-retirement proposals.
2. Whether the IRP’s modeling and narrative support adequately addressed Wyoming-specific impacts and assumptions—particularly community impacts, carbon-cost inputs, and the absence of carbon-capture analysis—given the proposed early retirement of coal-fired generation in Wyoming.
3. What conclusions or expectations the Commission would state in its report to guide future IRP filings and later proceedings that might seek approval of retirements, new resources, or related cost recovery.

## Decision

- The Commission opened and conducted an investigation under Wyoming Stat. § 37-2-117 focused on the coal study and the October 18, 2019 IRP because the IRP depended on the coal study and proposed a large shift away from Wyoming coal generation.
- The Commission issued a report after receiving staff review and testimony, including testimony from local governments concerning social and economic harms tied to premature coal-plant closures.
- The Commission found that the IRP, as filed, contained analytical gaps identified in the investigation record, including limited analysis weighing Wyoming community harms against asserted portfolio benefits, reliance on carbon-cost assumptions viewed as insufficiently supported in the record, and failure to analyze carbon-capture technologies.
- The Commission’s report communicated that these gaps mattered to the Commission’s evaluation of the IRP as a planning document and to how the Commission would view similar assumptions or proposals in future IRPs and later filings seeking Commission approval.

## Legal Principles

- Under Wyoming Stat. § 37-2-117, the Commission may initiate an investigation on its own motion into matters connected to public-utility service and the information presented to the Commission in utility planning filings.
- An integrated resource plan functions as a planning and informational filing; proposals described in an IRP do not, by themselves, constitute Commission authorization for plant retirements, construction, or cost recovery.
- When an IRP relies on modeling inputs that materially affect outcomes—such as assumed carbon costs—the utility must provide record support sufficient for the Commission to evaluate the reasonableness of those assumptions for Wyoming customers.
- When early retirement of Wyoming generating units is proposed, the Commission expects analysis that meaningfully addresses Wyoming community and local-government impacts, including whether claimed portfolio benefits justify those impacts.
- Where technology alternatives could change the retirement analysis—such as carbon-capture options for coal units—the Commission may expect the IRP to evaluate those alternatives rather than omit them.

## Conclusion

In this Commission investigation proceeding, the Wyoming Public Service Commission examined Rocky Mountain Power’s October 18, 2019 IRP and the coal-system-optimization study that supported early retirement assumptions, heard testimony about the harms to Wyoming workers and communities, and issued a report identifying shortcomings in the IRP’s treatment of community impacts, carbon-cost assumptions, and carbon-capture alternatives that the Commission viewed as necessary for meaningful review of such planning proposals.


In the Matter of the Commission's Investigation Pursuant to Wyoming Stat. § 37-2-117 of the Integrated Resource Plan Filed by Rocky Mountain Power on October 18, 2019, 2021 WL 365177 (2021)