Federal solar credit ended Dec 31, 2025
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Net metering · Montana

Montana Net Metering and Solar Export Credits

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Updated Data verified Nov 5, 2026

Net metering. Montana law requires NorthWestern Energy and Montana-Dakota Utilities to offer net metering for home systems under 50 kW: exports offset your usage kWh for kWh at the retail rate, and a month's surplus carries forward as a kWh credit on the next bill. At the end of your chosen 12-month period (starting Jan 1, Apr 1, Jul 1 or Oct 1) any unused credits go to the utility without payment, and you still pay the normal monthly customer charge.

On this page [ 4 ]

State rules that apply

  • What the rule says: “credited for the excess kilowatt hours generated during the billing period, with this kilowatt-hour credit appearing on the bill for the following billing period.”[1]

What it means for sizing and batteries

When exports earn close to the retail price, sizing the system to cover your yearly use is usually the best value, and a battery is mainly for backup rather than savings.

The calculator uses the statewide rule until we add utility rates. See what solar costs in Montana.

FAQ

Frequently asked questions

Does Montana have net metering?

Montana law requires NorthWestern Energy and Montana-Dakota Utilities to offer net metering for home systems under 50 kW: exports offset your usage kWh for kWh at the retail rate, and a month's surplus carries forward as a kWh credit on the next bill. At the end of your chosen 12-month period (starting Jan 1, Apr 1, Jul 1 or Oct 1) any unused credits go to the utility without payment, and you still pay the normal monthly customer charge.

sources

[ 1 ]

Every number on this page links to one of these sources. Dates show when we last checked each one.

  1. Montana Code Annotated 2025, 69-8-603 Net energy measurement calculationmca.legmt.gov · checked Nov 5, 2026

Tariffs last re-checked November 5, 2026.

Change log

  1. Monthly output per kW in Billings updated to [64.5, 78.1, 114.9, 124.0, 144.4, 151.3, 166.3, 151.8, 124.5, 99.9, 66.5, 57.6] kWh/kW/month (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).
  2. Average solar radiation on the panels in Billings updated to 4.76 kWh/m2/day (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).
  3. Solar output per kW in Montana (PVWatts, Billings) updated to 1343.9 kWh/kW/yr (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).
  4. What the rule says updated to “credited for the excess kilowatt hours generated during the billing period, with this kilowatt-hour credit appearing on the bill for the following billing period.” (Montana Code Annotated 2025, 69-8-603 Net energy measurement calculation).