NorthWestern Energy electricity rates
Investor-owned utility · South Dakota · MRO region · SPP
NorthWestern Energy is a for-profit, investor-owned utility regulated by the state utility commission, serving 51,787 homes in South Dakota. Its residential customers pay an average of 14.13¢/kWh including fixed and delivery charges, 21% less than the U.S. average.
Rate basis: EIA-861M monthly utility data, 12 months ending 2026-07.
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NorthWestern Energy bill estimates
| Monthly use | At average all-in rate | Base tariff charges* |
|---|---|---|
| 500 kWh | $70.65 | $93.55 |
| 1,000 kWh | $141.30 | $177.56 |
| 1,500 kWh | $211.95 | $235.24 |
| 2,000 kWh | $282.60 | $284.24 |
*Rate 10: Residential Electric (effective 2025-05-01, $7.00/month customer charge), energy and fixed charges from the OpenEI Utility Rate Database. Riders, fuel adjustments and taxes are often billed separately, so real bills usually land closer to the all-in column. Calculate your bill.
NorthWestern Energy residential rate plans
| Plan | Effective | Customer charge | Energy charges |
|---|---|---|---|
| Rate 10: Residential Electric | 2025-05-01 | $7.00 | 17.42¢ first 200 kWh, 17.24¢ first 800 kWh, 16.15¢ first 1,000 kWh, 14.14¢ first 1,200 kWh, 9.80¢ after |
| Rate 15: Residential Dual Fuel and Controlled Service. | 2025-05-01 | $4.00 | 10.90¢ |
| Rate 14: Residential Space Heating and Cooling | 2025-05-01 | $4.00 | 10.90¢ |
| Rate 11: Residential Service with Space Heating | 2025-05-01 | $7.00 | 17.42¢ first 200 kWh, 17.24¢ first 800 kWh, 16.15¢ first 1,000 kWh, 14.14¢ first 1,200 kWh, 9.80¢ after |
Source: OpenEI U.S. Utility Rate Database. Rates change. Check the linked tariff or your bill for current figures.
NorthWestern Energy rate history
2015–2025: +49% change in the average residential rate (8.98¢ → 13.35¢). Annual EIA-861 data.
Outages & reliability
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Reliability history
| 2025 | NorthWestern Energy | South Dakota avg | U.S. avg |
|---|---|---|---|
| Outage minutes per customer (SAIDI) | 120 | 257 | 266 |
| Outages per customer (SAIFI) | 1.14 | 1.24 | 1.34 |
| Average restoration time (CAIDI) | 105 min | — | — |
| Outage minutes excluding major storms | 82 | 63 | 121 |
Outages in counties served (2025)
From ORNL EAGLE-I, which tracks customers without power every 15 minutes. These counts cover every utility in each county. Weighted across NorthWestern Energy's counties, customers averaged 2 hr 14 min without power.
| County | Outage min/customer | Days with outages | Peak customers out | Worst day |
|---|---|---|---|---|
| Marshall | 874 | 26 | 692 | 2025-08-16 |
| Sanborn | 598 | 16 | 730 | 2025-08-16 |
| Clark | 468 | 11 | 1,953 | 2025-06-11 |
| Bon Homme | 455 | 7 | 4,222 | 2025-03-15 |
| Turner | 393 | 16 | 983 | 2025-07-30 |
| Deuel | 376 | 23 | 1,039 | 2025-02-13 |
| Day | 324 | 21 | 1,447 | 2025-11-25 |
| Spink | 210 | 14 | 1,192 | 2025-12-10 |
| Beadle | 192 | 12 | 6,410 | 2025-07-23 |
| Faulk | 188 | 5 | 447 | 2025-06-24 |
| Hamlin | 174 | 14 | 930 | 2025-06-28 |
| Hanson | 164 | 3 | 848 | 2025-07-29 |
| Yankton | 136 | 18 | 1,953 | 2025-02-18 |
| Hutchinson | 115 | 14 | 1,979 | 2025-11-30 |
| Brown | 112 | 16 | 1,838 | 2025-10-29 |
| Edmunds | 111 | 10 | 527 | 2025-05-11 |
| Aurora | 111 | 5 | 701 | 2025-11-30 |
| Davison | 90 | 21 | 1,458 | 2025-07-30 |
| Kingsbury | 82 | 11 | 319 | 2025-08-16 |
| Jerauld | 72 | 1 | 181 | 2025-08-16 |
| Hyde | 63 | 4 | 471 | 2025-05-15 |
| Douglas | 61 | 1 | 142 | 2025-07-30 |
| Charles Mix | 51 | 3 | 631 | 2025-07-29 |
| Brule | 44 | 3 | 284 | 2025-05-15 |
| Codington | 7 | 6 | 330 | 2025-12-10 |
NorthWestern Energy service area
NorthWestern Energy serves 27 counties in South Dakota and 36 ZIP codes.
Aurora, Beadle, Bon Homme, Brown, Brule, Charles Mix, Clark, Codington, Davison, Day, Deuel, Douglas, Edmunds, Faulk, Hamlin, Hand, Hanson, Hughes, Hutchinson, Hyde, Jerauld, Kingsbury, Marshall, Sanborn, Spink, Turner, Yankton
Cities: Aberdeen, Yankton, Huron, Chamberlain, Springfield, Webster, Clark, Tyndall
Programs, smart meters & solar
| Smart meters (AMI) for homes | 100% |
| Time-based rate programs | None reported |
| Net-metered solar homes | 0 reported |
NorthWestern Energy at a glance
| Ownership | Investor-owned utility |
| Services | Generation, Transmission, Distribution, Wholesale Marketing, Bundled |
| Commercial rate | 13.81¢/kWh |
| Industrial rate | 9.39¢/kWh |
| Retail revenue (2025) | $201,480,000 |
| Electricity sold (2025) | 1,656,248 MWh |
| Peak demand | 327 MW summer · 319 MW winter |
| Power from own generation | 38% (rest purchased) |
| Balancing authority | SWPP |
| EIA utility ID | 13809 |
Other utilities in South Dakota
Frequently asked questions
What is NorthWestern Energy's electricity rate?
NorthWestern Energy residential customers pay an average of 14.13¢ per kWh, all charges included (EIA-861M monthly utility data, 12 months ending 2026-07). That's 0% below the South Dakota average of 14.20¢ and 21% below the U.S. average.
What is the average NorthWestern Energy electric bill?
About $133 a month. The average NorthWestern Energy home uses 939 kWh a month. At 1,000 kWh the bill would be about $141.
How many customers does NorthWestern Energy have?
NorthWestern Energy serves 51,787 residential customers and 65,396 customers in total in South Dakota, across 27 counties.
How reliable is NorthWestern Energy?
In 2025, the average NorthWestern Energy customer was without power for 120 min (SAIDI) over 1.14 interruptions (SAIFI), including major storms. Excluding major event days it was 82 min. The South Dakota average was 4 hr 17 min and the U.S. average 4 hr 26 min.
Sources: EIA-861 2025 and EIA-861M (through July 2026), OpenEI URDB, ORNL EAGLE-I, U.S. Census. Methodology. Spot an error? Rates change often, so confirm with NorthWestern Energy before making decisions.