Declare authority over existing fossil-fuel fired electric generating units

This bill declares that the Montana Department of Environmental Quality has full authority over air quality, water quality, and emissions standards for existing fossil fuel-fired electric generating units within the state. It designates the department as the sole oversight and permitting authority for coal, natural gas, and oil power plants currently operating in Montana, while asserting that federal agencies lack authority to regulate these facilities without significant economic investment from owners and ratepayers. The legislation includes a contingency clause that would void the bill if the federal Environmental Protection Agency repeals specific rules from May 2024, and it takes effect immediately upon passage and approval.