Document pB67dvdZxmrNGveypZeNVMbaa

NorthWestern Erier g Delivering a Bright Future North Western currently has over 200 percent more wind generation than its Colstrip generation. In terms of generation asset nameplate capacity, thc two largest, by far, are hydroelectric assets and the fleet of wind farms, both of which arc carbon free. NorthWestern's portfolio of solar generating facilities has also been increasing in recent years. At the same time, it is important to note the difference between "nameplate" and "accredited" capacity. Nameplate capacity refers to the maximum electrical generating output (in MW) that a generator can sustain over a specified period of time when not restricted by seasonal or other "dcratings" (events that reduce effective output), as measured in accordance with thc Unitcd States Department of Energy standards. In contrast, accredited capacity means the electrical rating given to generating equipment that meets the Utility's criteria for uniform rating of equipment. These criteria include but are not limited to reliability, availability, type of equipment and the degree of coordination between the Distributed Generation and the Utility. Wind and solar accredited capacities are much lower than their nameplate capacities, because of the seasonal and wcathcr variability of those generation sources. Hydroelectric generation also has a gap between nameplate and accrcditcd capacity, reflecting periods when generation is restricted by stream flows. All this is reflected in the table below: Hydro Generation - Online Total 497 298 Thermal/Natural Gas Generation - Online Total 255 195 Thermal/Coal Generation - Online Total 309 288 Wind Generation - Online Total 455 59 Solar Generation - Online Total 97 1 Short Term Contracts - Max 460 460 In fact, while news coverage of NorthWcstcrn often discusses thc coal or natural gas facilities, thc proportion of NorthWestern's generation resources that are renewable compares highly favorable to other utilities. In 2022, 59% of NorthWestern's electric generation was from carbon-free resources, which compares to 40% of megawatt hours generated by the L.S. electric power industry as a whole. Sierra Club FOIA 2025-EPA-04883 ED_018388_00000308- 00010 SC_EVERSPLIT0006147