Solar in Montana: how the rules work
How Montana credits the power solar panels send back to the grid, what homes there pay for electricity, and what to check when a home with solar is bought or sold.
How exported power is credited
Power sent to the grid is credited at the full retail rate (kWh for kWh), at least within each billing period.
NorthWestern Energy (net metering for systems up to 50 kW under MCA 69-8-601 et seq.) nets kWh 1:1 at the full retail rate: excess generation in a month is banked as a kWh credit and carried forward to later bills until the customer's chosen annual settle-up month, when by Montana law any remaining excess credit resets to zero (forfeited, not paid out). Solar customers remain in the standard residential class and still pay the normal monthly service charge; there is no solar-specific fee or separate rate class. The Montana PSC rejected NorthWestern's 2019 bid to end net metering and create a separate solar rate class, and no later rate case has changed this. In the 2025 session HB 811 and HB 670 (raise the cap to 100 kW, redirect forfeited year-end credits to low-income aid) were tabled, so the law is unchanged as of Sept 2026. Because nothing has been reduced, there is no grandfathering or cutoff date.
What changes for a home with solar
A savings estimate that counts exported power at the full retail rate matches how exports are credited here. Where only month-end surplus earns a lower rate, homes that use most of their power themselves come closest to that estimate.
Electricity here costs about 14.0¢ per kWh (2026) and has risen about 2.2% a year over the last decade. A lease or PPA escalator above that pace makes the solar payment rise faster than utility rates have.
When a home with solar is sold in Montana
- Owned outright: proof it is paid off, the warranties, and the utility’s interconnection or net-metering agreement, which has to move into the buyer’s name.
- Loan: a payoff letter, and whether the buyer can assume the loan. Many solar loans are secured by a UCC-1 fixture filing that title will find.
- Lease or PPA: the transfer process and how long approval takes, the buyer’s credit check, the current payment or rate and its yearly increase, and a buyout quote.
- Every case: whether the export-credit terms above stay with the home after the sale, and the last 12 months of production from the monitoring app.
Have the solar contract for a Montana home?
Upload it and get a letter-graded report card: price, production, payment changes, value and transfer terms, measured against Montana’s rates and rules.
Grade a solar contractSources
- northwesternenergy.com/clean-energy/our-environmental-projects/net-metering-private-genera
- www.utilitydive.com/news/montana-rejects-northwesterns-bid-to-end-net-metering-add-separat (2019-11-19)
- meic.org/energy-bills-in-the-2025-legislative-session/ (2025)
- Electricity prices: EIA Electric Power Monthly, Table 5.6.B (2026) and EIA state annual averages 2014–2024
- Installed price: EnergySage marketplace, September 2026