Document yp0pqjwoeBYk5j3DJL52jwOYX

USCA Case #24-1190 Document #2062093 Filed: 06/27/2024 Page 3 of 92 Declaration is based on my personal knowledge as President of Talen Montana and Chief Fossil Officer of Talen Energy, and analyses conducted by my colleagues. 4. I am submitting this Declaration in support of Petitioners Talen Montana and North Western Corporation d/b/a NorthWestern Energy's Joint Motion to Stay the U.S. Environmental Protection Agency's ("EPA" or "Agency") final rule titled "National Emission Standards for Hazardous Air Pollutants: Coal- and OilFired Electric Utility Steam Generating Units Review of the Residual Risk and Technology Review," commonly referred to as the Mercury and Air Toxics Standards ("MATS"). 89 Fed. Reg. 38508 (May 7, 2024) ("MATS Final Rule"). 5. I am familiar with Talen Montana's operations, including generation, regulatory compliance, workforce management, and electric markets in general. I also am familiar with the MATS Final Rule, and I am familiar with how the MATS Final Rule will affect Talen Montana. Additionally, I am familiar with EPA's greenhouse gas rule, 89 Fed. Reg. 39798 (May 9, 2024) ("GI IG Rule"),' as described below. 6. Talen Montana has economic interests in coal-fired units that will be subject to the MATS Final Rule. [ See New Source Performance Standards for Greenhouse Gas Emissions From New, Modified, and Reconstructed Fossil Fuel-Fired Electric Generating Units; Emission Guidelines for Greenhouse Gas Emissions From Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of the Aftbrdable Clean Energy Rule, 89 Fed. Reg. 39798 (May 9, 2024). 2 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000309-00003 SC_EVERSPLIT0006166