Electricity rates — NorthWestern Energy
A household served by NorthWestern Energy using 1,000 kWh a month pays about $2,130.72 a year on the cheapest of 1 generally available plan — Rate 10: Residential Electric from NorthWestern Energy, in effect since May 2025. Rates checked September 23, 2026. A further 3 schedules are published but restricted — means-tested, closed to new customers, or needing particular equipment — and they are priced further down.
Every priced plan, 1,000 kWh/mo
| Plan | Per year | vs cheapest | Effective |
|---|---|---|---|
| Rate 14: Residential Space Heating and Coolingflat rate · in effect since May 2025 · needs electric heating | $1,356.12 | −$774.60 | 11.3¢ |
| Rate 15: Residential Dual Fuel and Controlled Service.flat rate · in effect since May 2025 · needs a dual-fuel or interruptible system | $1,356.12 | −$774.60 | 11.3¢ |
| Rate 10: Residential Electric✓ cheapesttiered · in effect since May 2025 | $2,130.72 | — | 17.8¢ |
| Rate 11: Residential Service with Space Heatingtiered · in effect since May 2025 · needs electric heating | $2,130.72 | — | 17.8¢ |
Cost across usage levels
The cheapest plan at each consumption level, showing whether the ranking holds as usage changes.
- 500 kWh/mo — cheapest $1,122.60 (Rate 10: Residential Electric), dearest $1,122.60
- 1,000 kWh/mo — cheapest $2,130.72 (Rate 10: Residential Electric), dearest $2,130.72
- 2,000 kWh/mo — cheapest $3,410.88 (Rate 10: Residential Electric), dearest $3,410.88
What a typical bill costs
At 1,000 kWh a month one plan here is open to any household — Rate 10: Residential Electric, at $2,130.72 a year. There is no cheaper option to move to, only the restricted schedules priced below.
Effective rates, bill divided by kilowatt-hours, come to 17.8¢ per kWh at that usage.
What NorthWestern Energy's customers were billed in 2024
NorthWestern Energy's open plans and its customers' bills disagree by more than a quarter: at 903 kWh a month, the median plan is 17.9¢ per kWh against 12.6¢ billed in 2024. Before relying on a plan price here, test it against a real NorthWestern Energy bill in the bill analyzer.
| Ownership, as EIA classes it | Investor-owned |
|---|---|
| Full-service homes in South Dakota | 51,467 |
| Share of South Dakota's households | 12% |
| Average use per home | 903 kWh a month |
| Average bill per home | $113.36 a month |
| Billed per kWh, riders included | 12.6¢ |
| Median open plan here, at that use | 17.9¢ |
NorthWestern Energy - (SD) in U.S. Energy Information Administration, Form EIA-861, 2024 (Sales_Ult_Cust_2024.xlsx), retrieved September 23, 2026.
How it compares
Among the 109 utilities indexed, NorthWestern Energy's cheapest open plan is the 28th-highest, 29% more than their median of $1,649.16. It sits between Public Service Co of NM ($2,121.42) and Wisconsin Electric Power Co ($2,146.17).
Its fixed charge, $7.00 a month on Rate 10: Residential Electric, is lower than on the cheapest plan of 102 of the other 108 utilities.
Rate 10: Residential Electric is tiered: past 1,200 kWh a month, each kWh costs 4.3¢ less. Of the 51 utilities whose plans step, that is the 11th-largest step.
In the guides: What a bill costs before a single kilowatt-hour · The price that changes once the meter passes a line
How the answer changes with usage
Rate 10: Residential Electric is cheapest at every level tested — $1,122.60 a year at 500 kWh a month, $3,410.88 at 2,000 kWh.
Cheapest 4 plans at 1,000 kWh a month
Rate 14: Residential Space Heating and Cooling — $1,356.12 a year, 11.3¢ per kWh effective, flat rate. It carries a $4.00 monthly standing charge. In effect since May 2025. Restricted: needs electric heating.
Rate 15: Residential Dual Fuel and Controlled Service. — $1,356.12 a year, 11.3¢ per kWh effective, flat rate. It carries a $4.00 monthly standing charge. In effect since May 2025. Restricted: needs a dual-fuel or interruptible system.
Rate 10: Residential Electric — $2,130.72 a year, 17.8¢ per kWh effective, tiered. It carries a $7.00 monthly standing charge. In effect since May 2025.
Rate 11: Residential Service with Space Heating — $2,130.72 a year, 17.8¢ per kWh effective, tiered. It carries a $7.00 monthly standing charge. In effect since May 2025. Restricted: needs electric heating.
How these plans are structured
Of 4 priceable plans: 2 tiered, 2 flat-rate.
Fixed monthly charges run from $4.00 to $7.00.
Who provides these plans
EIA-861 lists NorthWestern Energy serving homes in South Dakota and in no other state, which is how its plans are placed there. 4 of its 4 published residential schedules can be priced.
New to these terms? The methodology page explains tiered bands, time-of-use periods and fixed charges, and sets out exactly what the rate engine assumes.
Estimate — your actual bill may differ.
Tariff structures from NREL/OpenEI Utility Rate Database (CC0 1.0), retrieved September 23, 2026.