NorthWestern Energy LLC - (MT)
Investor Owned electric utility · Montana · #94 of 3,199 U.S. utilities by customers · EIA utility #12825
NorthWestern Energy LLC - (MT) is a investor owned electric utility serving 439,003 customers in Montana, Wyoming. In 2025 it sold 6,412 gigawatt-hours of electricity for $878.25M in revenue, an average realized rate of 13.70¢ per kWh across all customer classes and 14.42¢ per kWh for residential customers. Its reported service territory covers 38 counties. EIA records its activities as: generation, transmission, buying transmission, distribution, retail marketing.
Customers, sales and rates by customer class (2025)
| Class | Customers | Sales (GWh) | Revenue | Avg realized rate | Share of sales |
|---|---|---|---|---|---|
| Residential | 334,010 | 2,834 | $408.71M | 14.42¢ | |
| Commercial | 102,582 | 3,165 | $426.19M | 13.47¢ | |
| Industrial | 2,411 | 413 | $43.35M | 10.49¢ | |
| Total | 439,003 | 6,412 | $878.25M | 13.70¢ |
Average realized rate = revenue divided by sales as reported on EIA Form 861. It blends fixed charges, demand charges and riders into one per-kWh figure; it is not the utility's tariff rate. Estimated residential bill assumes the average residential customer's actual 2025 usage (707 kWh/month).
Operations by state
| State | Customers | Sales (GWh) | Residential rate |
|---|---|---|---|
| Montana | 438,311 | 6,381 | 14.42¢ |
| Wyoming | 692 | 30.8 | 12.39¢ |
Five-year trend
| Year | Customers | Sales (GWh) | Revenue | Residential rate |
|---|---|---|---|---|
| 2021 | 389,098 | 6,194 | $733.39M | 12.14¢ |
| 2022 | 395,708 | 6,407 | $771.07M | 12.43¢ |
| 2023 | 402,618 | 6,322 | $895.77M | 14.61¢ |
| 2024 | 415,570 | 6,341 | $865.39M | 14.23¢ |
| 2025 | 439,003 | 6,412 | $878.25M | 14.42¢ |
Reliability (2025)
Average outage time (SAIDI): 125 minutes per customer per year
Average outages (SAIFI): 1.10 per customer
Average restoration time (CAIDI): 114 minutes
As reported for Montana under the IEEE standard, with major event days included where the standard reports them. Lower is better; see the reliability rankings.
Energy supply (2025)
Net generation: 4,604 GWh
Wholesale power purchased: 3,245 GWh
Winter peak demand: 2,046 MW
Energy losses: 8.3% of energy handled
Meters & rooftop solar (2025)
Smart (AMI) meters: 96.1% of 439,543 meters
Customer-sited generation (net metering): 12,346 installations, 98.6 MW of capacity
This utility also reported 540 delivery-only customers (2,688 GWh delivered) in 2025. Delivery figures are excluded from the totals above because the same electricity is also reported by the energy supplier - see Methodology.
Counties served
Beaverhead, MTBig Horn, MTBlaine, MTBroadwater, MTCarbon, MTCascade, MTChouteau, MTDeer Lodge, MTFergus, MTGallatin, MTGolden Valley, MTGranite, MTHill, MTJefferson, MTJudith Basin, MTLewis and Clark, MTLiberty, MTMadison, MTMeagher, MTMineral, MTMissoula, MTMusselshell, MTPark, MTPark, WYPhillips, MTPondera, MTPowell, MTRavalli, MTRosebud, MTSanders, MTSilver Bow, MTStillwater, MTSweet Grass, MTTeton, MTTeton, WYValley, MTWheatland, MTYellowstone, MT
Other large utilities in Montana
- Flathead Electric Coop Inc - 77,288 customers, residential 10.04¢
- Yellowstone Valley Elec Co-op - 23,683 customers, residential 14.22¢
- USBIA-Mission Valley Power - 23,250 customers, residential 9.39¢
- Missoula Electric Coop, Inc - 16,781 customers, residential 10.93¢
- Ravalli County Elec Coop, Inc - 12,194 customers, residential —
- Glacier Electric Coop, Inc - 7,964 customers, residential —
- Fergus Electric Coop, Inc - 7,157 customers, residential 15.91¢
- Lincoln Electric Coop, Inc - 6,909 customers, residential —
All Montana utilities and rates
Source: U.S. Energy Information Administration, Form EIA-861 2025 (filed by the utility; figures as published). Utility #12825 in the EIA frame.