Document 5DMwX8Roge6K1y36ddX4paGa4

NorthWestern Energy Delivering a Bright Future most commonly happens during peak events, but also during non-peak events. That is the reason NorthWestern currently has no remaining firm import ATC posted on Path 80. Path 83 provides transmission capacity between Montana and Canada. Path 83 consists of a single 230 kV line -- the Montana Alberta Tie Line, which is not owned by North Western. Most of the activity on the Path is related to wind projects located in north central Montana, also not owned or controlled by North Western. Additionally, Path 83 is a very complex path that routinely must be curtailed to manage generation and loads. This path also contributes significantly to our challenges and limitations across an internal path we refer to as "South of Great Falls". The South of Great Falls path frequently must be curtailed and has impacts on thc Great Falls, Billings, Helena and Butte areas. Path 18 has relatively smaller overall capacity and is highly utilized today with little import capacity remaining. As described in Paragraph 23 below, for several years ending in 2012 NorthWestern attempted to permit an upgrade to thc transmission capacity of Path 18 through thc proposed Mountain States Transmission Intcrtic ("MSTI"). Ultimately, that effort failed. Consequently, Path 18 offers little potential for increased imports at this time. In summary, ATC is quite limited for import into the North Western BAA. Figure 2 below is a snapshot as of February 23, 2023 of long-term firm ATC that is posted on NorthWestern's Open Access Same-time Information System ("OASIS") for cach ycar displayed. The OASIS provides real-time, up-to-date information and access to transmission system capacity for all customers. Figure 2 clearly indicates that thcrc is very little to zero firm ATC to import from any Path of import. 16 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000308- 00017 SC_EVERSPLIT0006154