Montana Solar Estimate

Investor-owned utility (PSC-regulated)

Solar with NorthWestern Energy

NorthWestern Energy members pay 15.8¢ per kWh and no demand charge; a typical home's solar pays back in about 13 years.

See the numbers for your address

At a glance

Energy rate
15.8¢/kWh
flat rate
Fixed charge
$4/mo
billed every month, solar or not
Demand charge
None
every offset kWh saves the full rate
Net-metering limit
50 kW AC
bank resets in April

Residential schedule effective October 15, 2026; checked November 1, 2026. Sources.

What this means for solar

  • Excess power is banked as kWh at the full retail rate and drawn down in later months. The bank resets in April (or another quarter you choose), and anything left is forfeited to the utility.
  • NorthWestern Energy has no residential demand charge, so every kWh solar offsets saves the full energy rate.
  • Systems up to 50 kW AC qualify for net metering; above that, capacity would run without export credit.
  • There is a $200 interconnection fee.

A typical home: 900 kWh a month, gas heat

Net-zero system
9.3 kW
1163 kWh per kW per year
Installed cost
as low as$22,591
up to $27,611
First-year savings
up to$1,795
at least $1,575
Payback
as low as11.2 yrs
11.2–15 yrs at 2.7%/yr

Best-case figures with the range shown; no federal credit for homes in 2026. Production reference: Polson. Your roof, usage and heating change every number, which is what the estimate is for.

Full schedule and net-metering rules
Fixed charge
$4 per month
Energy
15.83¢ all kWh
Net metering
Rule 16 (MCA 69-8-601 et seq.): generation plus storage up to 50 kW AC; excess kWh carried forward and granted to NorthWestern without compensation at the annual settle-up (January, April, July or October, customer's choice); bidirectional meter at no charge; $200 Level 1 processing fee.
Notes
Flat rate, no seasons. The supply component (PCCAM) moves quarterly: PSC summary showed 16.80c Jul-Sep and 15.65c Oct 1, 2026. No new general rate case filed; Black Hills merger pending.
Effective
October 15, 2026; checked November 1, 2026

Questions members ask

Does NorthWestern Energy pay for excess solar power?
Excess power is banked as kWh at the full retail rate and drawn down in later months. The bank resets in April (or another quarter you choose), and anything left is forfeited to the utility.
How big a solar system can I net-meter with NorthWestern Energy?
Systems up to 50 kW AC qualify for net metering. The interconnection fee is $200.
Does NorthWestern Energy have a demand charge?
NorthWestern Energy has no residential demand charge, so every kWh solar offsets saves the full energy rate.
What would solar cost and save for a typical NorthWestern Energy home?
For a gas-heated home using about 900 kWh a month, a net-zero system is about 9.3 kW, costs roughly $22,591 to $27,611 installed, saves $1,575 to $1,795 in the first year, and pays back in 11.2 to 15 years at 2.7% a year rate growth. Your address gives a real figure in about a minute.
What federal incentives apply in 2026?
The 30% homeowner credit (Section 25D) ended for systems completed after December 31, 2025. Business-owned systems, including ranches, farms and rental property, still qualify for the 30% investment credit (Section 48E) and bonus depreciation when placed in service by the end of 2027; tax-exempt owners receive the 30% as a cash payment. Not tax advice.
Where do these numbers come from?
The rate figures are read from NorthWestern Energy's own published schedule and net-metering policy (linked under Sources), last checked November 1, 2026. The worked example runs the same engine as the estimator, using a production reference for Polson and Montana installed-cost data. If you spot an error, email us and we will correct it.

Service area

Montana-Dakota UtilitiesLincoln Electric CooperativeLower Yellowstone Rural Electric CooperativeMarias River Electric CooperativeMcCone Electric CooperativeMid-Yellowstone Electric CooperativeMissoula Electric CooperativeNorVal Electric CooperativeBeartooth Electric CooperativePark Electric CooperativeBig Flat Electric CooperativeSheridan Electric CooperativeBig Horn County Electric CooperativeSoutheast Electric CooperativeSun River Electric CooperativeTongue River Electric CooperativeCity of Troy ElectricMission Valley PowerYellowstone Valley Electric CooperativeFergus Electric CooperativeVigilante Electric CooperativeRavalli Electric CooperativeFlathead Electric CooperativeGlacier Electric CooperativeHill County Electric CooperativeNorthWestern Energy
NorthWestern Energy's service territory (highlighted). Hover a region to see its utility.

Other Montana utilities: Montana-Dakota Utilities. All 26 utilities.

Sources

Every figure on this page comes from the documents below. We print the schedule’s effective date and the date we last read it; when a utility publishes nothing, we say so instead of guessing quietly.

  1. Residential rate schedule: fixed charge, energy rate
    NorthWestern REDS-1 (78th rev.) + ESS-1 compliance sheets effective Oct 15, 2026 (Docket 2024.05.053) and the Oct 15, 2026 rates-at-a-glance workbook: $4.20 customer charge; 15.827c/kWh all-in (delivery 5.51c, supply incl. deferred and tax 8.01c, transmission 1.58c, riders 0.73c); $122.90 at 750 kWh
    Effective October 15, 2026 · Checked November 1, 2026 · Read from the primary source
  2. Net-metering / distributed-generation policy
    Rule 16 (MCA 69-8-601 et seq.): generation plus storage up to 50 kW AC; excess kWh carried forward and granted to NorthWestern without compensation at the annual settle-up (January, April, July or October, customer's choice); bidirectional meter at no charge; $200 Level 1 processing fee.
    Checked November 1, 2026 · Read from the primary source
  3. Service territory on the map
    HIFLD Electric Retail Service Territories (U.S. DHS / Oak Ridge National Laboratory), Montana subset, 2020 vintage; boundaries are coarse at town edges
    Checked October 31, 2026 · Read from the primary source
  4. Worked example: production, installed cost, savings and payback
    Montana Solar Estimate engine: PVGIS/NSRDB-based production reference for Polson (1163 kWh per kW per year after snow and orientation), installed-cost ladder (Montana cash-price range, Oct 2026), 2.7%/yr rate escalation and 0.5%/yr panel degradation
    Checked November 1, 2026 · Read from the primary source

Spot an error or a rate change? Email mtsolarestimate@gmail.com. How the estimate itself is built: methodology.

Your address, your numbers

Roof, usage and heating change everything above. The estimate takes about a minute and asks for no contact details.