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NorthWestern Energy (South Dakota) rates

NorthWestern Energy has one residential plan modelled here. A typical South Dakota home using 987 kWh a month pays about $159 a month.

Investor-owned 51,467 residential customers (EIA-861, 2024) Tariffs checked September 28, 2026

Typical all-in priceRate 10

01234567890123456789.0123456789¢/kWh
Rate 10$159/mo

Residential plans

PlanTypeFixed/moJuly pricesJanuary pricesJuly weekday windows
Rate 10
Residential Electric
Tiered $7.00 15.9¢ 0–200 kWh · 15.7¢ 200–800 kWh · 14.7¢ 800–1,000 kWh · 12.6¢ 1,000–1,200 kWh · 8.3¢ over 1,200 kWh 15.9¢ 0–200 kWh · 15.7¢ 200–800 kWh · 14.7¢ 800–1,000 kWh · 12.6¢ 1,000–1,200 kWh · 8.3¢ over 1,200 kWh None

Charging an EV on NorthWestern Energy

1,000 miles a month in a Tesla Model Y Long Range AWD (275 kWh from the wall, EPA 27.5 kWh/100 mi) at 7.2 kW, added to a typical South Dakota home’s use, on each plan’s cheapest start hour versus plugging in at 6 pm. Averaged over the year.

PlanBest startCharging, best startCharging from 6 pmWhole bill with EV
Rate 10Any$32/mo$32/mo$191/mo

With an EV charged at its best hour, the cheapest plan overall is Rate 10. Compare plans on your own usage.

How NorthWestern Energy’s plans work

Rate 10 (Residential Electric). In July the first 200 kWh a month cost 15.9¢ each; then 15.7¢ above 200 kWh a month, then 14.7¢ above 800 kWh a month, then 12.6¢ above 1,000 kWh a month, then 8.3¢ above 1,200 kWh a month. An average South Dakota home (1,146 kWh in July) goes past the first tier, so extra load such as an EV is priced higher. Fixed charge: $7.00 a month.

Prices on this page are all-in per kWh, before taxes: base rates, supply and every per-kWh rider in the utility’s current tariff sheets. Your bill shows them as separate lines, and riders can change between tariff revisions.

As a cross-check, NorthWestern Energy billed its residential customers an average of 12.56¢ per kWh in 2024 (revenue ÷ sales, EIA-861). A plan taken from URDB is shown only if its all-in price is consistent with that figure, adjusted for South Dakota’s price change since.

Sources for each plan

PlanEffectiveSeasonsSolar exportsSource and status
Rate 10
Transcribed from the utility’s tariff
August 1, 2026 Same pricing all year Not recorded in URDB Checked September 28, 2026
NorthWestern Energy SD Electric Rates Tariff Summary, August 1, 2026

Plans marked “Checked” were transcribed from the utility’s current tariff and rider sheets, all charges included, and are re-checked on the date shown in each file. Other plans come from the OpenEI U.S. Utility Rate Database (CC BY 4.0) and have not yet been checked line by line against the utility’s tariff. Always confirm the current rates on your utility’s website before switching plans.

Run the numbers on NorthWestern Energy