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NorthWestern Energy: what its customers actually pay

Data as of: EIA-861 annual 2024 (released 2025) · EIA monthly state prices February 2026 · EIA weekly heating-fuel survey Mar 30, 2026 · retail-choice registry reviewed Jun 2026 · URDB tariffs pulled Jun 2026. Page generated 2026-06-12.

NorthWestern Energy residential customers paid an average of 12.56¢/kWh in 20244% below the South Dakota average of 13.02¢/kWh (EIA-861). It served 51,467 residential customers across 27 SD counties. Territories are fixed by address, but the cheapest nearby utility, Watertown Municipal Utilities (9.30¢), works out about $352/yr less at 10,800 kWh/yr.

How NorthWestern Energy compares with the utilities next door

Utilities filing EIA-861 service territory in at least one county that NorthWestern Energy also serves — average residential ¢/kWh (EIA-861 2024) and annual cost difference vs NorthWestern Energy at 10,800 kWh/yr
Utility2024 ¢/kWhCustomersΔ vs NorthWestern Energy, ¢/kWh$/yr difference
Watertown Municipal Utilities 9.30 11,633 -3.26 -$352
City of Pierre 10.65 6,126 -1.91 -$206
Otter Tail Power Co 10.93 9,048 -1.63 -$176
Northern Electric Coop, Inc 11.29 5,757 -1.27 -$137
Southeastern Electric Coop Inc 12.41 20,160 -0.15 -$16
NorthWestern Energy (this page) 12.56 51,467
Sioux Valley SW Elec Coop 12.94 22,213 +0.38 +$41
Central Electric Coop, Inc 13.64 6,483 +1.09 +$117
Northern States Power Co - Minnesota 13.87 92,204 +1.31 +$141
Montana-Dakota Utilities Co 14.60 6,367 +2.04 +$220

9 bundled utilities (≥5,000 customers) share at least one county with NorthWestern Energy. Positive $/yr = that utility's customers pay more than NorthWestern Energy customers at the same usage. Territories are fixed by address — these gaps measure cost differences between areas, not options you can pick between.

Where NorthWestern Energy customers pay more (county benchmark)

Counties served by NorthWestern Energy: cheapest bundled utility operating in the same county and the annual difference at 10,800 kWh/yr (EIA-861 2024)
CountyCheapest utility in countyTheir ¢/kWhNorthWestern Energy premium, $/yr
Charles MixMidAmerican Energy Co8.68 +$419
CodingtonWatertown Municipal Utilities9.30 +$352
HughesCity of Pierre10.65 +$206
DayOtter Tail Power Co10.93 +$176
DeuelOtter Tail Power Co10.93 +$176
HamlinOtter Tail Power Co10.93 +$176
KingsburyOtter Tail Power Co10.93 +$176
MarshallOtter Tail Power Co10.93 +$176

Multiple utilities in one county means adjoining territories, not household choice — you cannot switch wires companies. Showing the 8 highest-premium counties of 27 served.

Rate trend and size

NorthWestern Energy residential average price and customers, EIA-861 2023 vs 2024
Metric20232024Change
Average price, ¢/kWh11.2612.56+11.5%
Residential customers51,26151,467+0.4%

Ownership: Investor Owned. Statewide context: South Dakota electricity rates.

Supply vs delivery on a NorthWestern Energy bill

South Dakota is a regulated retail market — NorthWestern Energy customers cannot choose a different supplier; rates are set in utility-commission proceedings. Official information: puc.sd.gov.

Counties served (SD, EIA-861 2024)

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

Head-to-head comparisons

Questions people ask

Is NorthWestern Energy more expensive than other South Dakota utilities?
NorthWestern Energy customers paid an average 12.56 cents/kWh in 2024 — 4% below the South Dakota volume-weighted average of 13.02 cents (EIA-861, bundled residential service).
Can I switch away from NorthWestern Energy?
No — distribution territory is fixed by address and South Dakota has no residential supplier shopping. Rate changes go through the state utility commission (puc.sd.gov).
How many customers does NorthWestern Energy have?
51,467 residential customers in South Dakota in 2024 across 27 counties, per its EIA-861 federal filing. Ownership type: investor-owned.
About these numbers. Rates shown are averages computed from federal regulatory filings (EIA Form 861) and public tariff databases — confirm with your utility before making decisions; your actual rate depends on your tariff, usage, and riders. Distribution utility is determined by address and generally cannot be chosen; in retail-choice states you may choose your supplier for the supply portion of the bill. Savings figures use 10,800 kWh/yr (US average residential usage) and are estimates, not quotes. EnergySavings is an independent data project by CertiHomes and is not affiliated with any utility, supplier, or government agency.