NorthWestern Energy is a regulated electric and natural gas utility serving roughly 850,300 customers across Montana, South Dakota, and Nebraska, operating as the monopoly utility in its service territories. The electric business is the larger operation, centered on Montana, where NorthWestern owns and operates a diversified generation fleet — including 470 MW of hydroelectric, 814 MW of coal (55% of Colstrip Units 3 & 4), 325 MW of natural gas, and 51 MW of wind — alongside transmission and distribution infrastructure. The natural gas business distributes gas primarily for heating, with demand concentrated in the first and fourth quarters. As a regulated utility, NorthWestern earns a return by investing in infrastructure and charging rates approved by state regulators, with a rate base of approximately $5.6B. The main earnings driver is rate base growth, with a five-year capital plan of approximately $3.2B targeting 4%–6% annual rate base and EPS growth. A key complication is regulatory lag in Montana, where new investments may not flow into customer rates for 18–24 months. NorthWestern's near-term growth opportunities include serving large-load data center customers in Montana using capacity from the recently acquired Colstrip interests, FERC regional transmission investment, and a planned 131 MW gas plant in South Dakota. In August 2025, NorthWestern agreed to merge with Black Hills in an all-stock deal, which would create a combined utility with approximately $11B in rate base, renamed Bright Horizon Energy, expected to close in 2026.