Larimer County approves Platte River’s Rawhide 10‑41 permit after hours of debate over turbines, air impacts

Larimer County commissioners on April 20 approved Platte River Power Authority’s 10‑41 land use permit for new aeroderivative natural‑gas turbines at the Rawhide Energy Station, subject to conditions requested by the board. The motion passed 3‑0 after a daylong hearing that drew more than 400 public comments and competing expert testimony on air impacts, alternatives and reliability.

The project would site five aero‑derivative turbines at the existing Rawhide plant and, Platte River’s attorney Kathleen Pritchard told commissioners, would allow the utility to retire coal generation and add large amounts of wind and solar while keeping power reliable. “The question before you is whether Platte River’s application complies with the applicable review criteria of the land use code,” Pritchard said during the applicant presentation.

County planning staff and the Larimer County Planning Commission recommended approval. Cassidy Fiore, a principal planner, told the board that staff “have reviewed the additional information and public comment provided and can confirm that the additional information as provided by the applicant addresses the request for additional information and continues to meet the applicable criteria of approval for 10‑41 permits as contained in the Larimer County land use code.” The commissioners added conditions designed to provide more transparency about regional market participation, interim emissions during the coal‑to‑gas transition, and long‑term hydrogen planning.

Why this matters: Platte River is the wholesale power provider for Fort Collins, Loveland, Longmont and Estes Park. Commissioners and the public debated whether the new turbines are necessary to allow Platte River to retire coal units while keeping lights on during periods of low wind and solar production. Opponents focused on local ozone and nitrogen oxide (NOx) contributions and urged smaller capacity or additional operational limits on high‑ozone days. Supporters — including municipal leaders and neighboring utilities — said the turbines are an essential reliability tool that will enable a much larger buildout of renewables and large cuts in CO2 emissions.

What the board decided - Motion: approval of the Rawhide 10‑41 permit as conditioned (motion moved by Commissioner Kefalas). The board voted 3‑0 to approve. - Key conditions added by the board require: (1) a staff‑reviewable analysis explaining how Platte River’s Southwest Power Pool (SPP West) participation will be used to manage renewable intermittency and potentially reduce gas capacity needs; (2) a commitment to consult with county staff and CDPHE on best management practices to reduce operations and emissions on forecasted high‑ozone days where feasible; (3) a transparent analysis comparing the IRP’s smaller gas portfolios (e.g., a ~160 MW option) with the proposed turbine portfolio, provided in technical review; (4) reporting and interim emission provisions addressing the overlap period as Rawhide transitions from coal to new units; and (5) periodic reporting on the viability of hydrogen conversion and an alternative emissions‑reduction plan if hydrogen conversion does not materialize.

Debate and evidence presented - Applicant case: Platte River argued the turbines are needed to balance large, rapid swings in wind and solar output and to replace coal while keeping power reliable and affordable. The applicant said sea‑level ratings for the turbine models are derated at Colorado elevations: the five machines cited would produce roughly 200 MW at local altitude rather than the 285 MW nameplate cited at sea level. Platte River also pointed to a recently announced 100 MW/4‑hour battery contract with NextEra as part of a portfolio that includes demand‑side resources and virtual power‑plant development. - Air quality and ozone: opponents including Northern Colorado Partners for Clean Energy, the Sierra Club and local residents urged denial or stricter limits. Senior air quality engineer Matt Trevie for Platte River and other applicant experts presented air‑dispersion modeling submitted to the Colorado Air Pollution Control Division (CDPHE) that showed modeled concentrations below the National Ambient Air Quality Standards (NAAQS) in the screening and dispersion analyses provided. Trevie noted electric generating units account for a relatively small share of ozone precursors measured at some area monitors but did acknowledge any new combustion capacity adds NOx. - Alternatives and capacity sizing: critics argued the utility’s Integrated Resource Plan (IRP) included smaller new gas portfolios (e.g., ~160 MW) and asked why Platte River sought a larger portfolio here. Platte River representatives said the IRP examined…