Demand charges across the Plains and Mountain West: seven rate designs, compared

The demand charge is usually the line that decides whether a DC fast-charging site pencils at low utilization: a fee on the site's peak power draw, billed whether or not the stalls stay busy. ForgeAsset's coverage now includes seven Plains and Mountain West states — Montana, Idaho, Kansas, Nebraska, North Dakota, South Dakota, and Wyoming — and their filed tariffs answer the demand question seven different ways. Every rate below was digit-verified against the utility's own filed sheets in July 2026. Nothing here is advice; it is a description of what the filed tariffs say and how the model prices them.

The clean case: Montana#

NorthWestern Energy's general-service rate bills demand at about $14.36 per kW of the month's 15-minute peak — all hours, no ratchet clause, no time-of-use window, no seasonal variation. The filed demand section is one line, and the bill moves only with the site's own peak. Montana's utility taxes are already inside the filed rates, and the state levies no general sales tax, so the modeled rate is the billed rate.

The stacked case: Idaho and Wyoming#

Idaho Power's Schedule 19 and Rocky Mountain Power's Wyoming Schedule 46 both build the demand bill from several filed components: a base charge on the monthly peak, a charge keyed to trailing twelve-month demand, and a component measured inside a daily on-peak window. For a charging site that draws its full hardware peak every day, each component resolves to the same monthly peak — so the model prices the stack as a single per-kW figure (about $17.27 in Boise; about $34.04 in Casper, the heaviest in the covered Rocky Mountain jurisdictions) and that mapping only overstates where the daily-peak assumption bends. Wyoming pairs its heavy demand stack with the covered set's cheapest energy, near 3 to 4 cents — the classic utilization trade, priced explicitly.

The EV-rate case: Kansas#

Evergy files a Business Electric Vehicle Charging Service schedule in both of its Kansas jurisdictions — a rate designed for charging sites, with time-of-use energy and no demand charge beyond a facility charge of about $3 per kW. The facility charge bills on the trailing twelve-month maximum including the current month, which resolves to the current month for a steady billed peak. At a fifth to a tenth of a standard large-commercial demand burden, the design changes what the ramp years cost.

The public-power case: Nebraska#

Nebraska is the only all-public-power state, and its two metro systems price the same load differently: Omaha Public Power District bills about $9.22 per kW — among the lowest demand rates in the covered set — against 7-cent energy, while Lincoln Electric System sells 3-cent energy against a facilities-weighted $27 per kW. A Lincoln site models at roughly twice an Omaha site's electricity cost at default utilization. Both schedules carry seasonal ratchet clauses that never bind for a site with a steady peak.

The disappearing case: the Dakotas#

Xcel Energy's general-service schedules in both Dakotas cap billing demand at monthly energy divided by a fixed hour count — kWh÷100 in North Dakota, kWh÷75 in South Dakota. A charging site's load factor sits far below the caps' breakeven, so the cap always binds, and the demand charge converts — exactly, by filed arithmetic — into a per-kWh adder inside the energy rate. The model carries a bundled energy rate (about 23 cents in Fargo, about 28.5 cents in Sioux Falls) with a structural zero on the demand line. Where a site's utilization ever exceeded the cap's envelope, the folded rate overstates the bill rather than understating it.

What the spread means for a site decision#

The same 1,500 kW site pays a monthly demand bill anywhere from zero (the Dakotas' cap fold, Kansas beyond the facility charge) to about $51,000 (Casper at full stack) before energy — on filed rates, not assumptions. That spread is why the model resolves the actual serving utility from the address and prices the filed structure, rather than applying a national average.

The filed demand-charge and time-of-use structure for every covered tariff is browsable in the demand-charge lookup, and each new state has an in-depth guide: Montana, Idaho, Kansas, Nebraska, North Dakota, South Dakota, and Wyoming. The full cost stack a site carries — demand charges included — is walked through in what it costs to host a Tesla Supercharger.