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Is plug-in solar legal in Montana?
What this means for you
✓ What you can do
- Apply for interconnection like any small generator (<=50 kW net metering), Not stated (gap).
- Use portable panels with a power station, never connected to house wiring, with no permission at all.
- Install conventional rooftop or ground-mount solar through the standard interconnection process.
✕ Not yet / not allowed
- Plug a grid-tied kit into an outlet without an interconnection agreement; it can breach your service terms.
- Expect a permit or wiring exemption; none exists without a law.
- Count on a law soon: no plug-in solar bill has been filed.
What the rules say
No plug-in solar law or bill in Montana.
Before you plug in: Montana checklist
- The rule that applies is Montana Public Service Commission's interconnection process: MCA 69-8-601 et seq. net metering; NWE interconnection agreement.
- A plug-in kit falls in the smallest tier (<=50 kW net metering). Not stated (gap).
- Permits: 2020 NEC; licensed electrician expected; homeowner permits allowed.
- Only consider kits with a UL 1741-listed inverter (UL 3700 preferred); a non-listed inverter will not be approved anywhere.
- What exports are worth: Retail kWh credit, reset to zero at annual settle-up.
- If approval is slow or costly, a portable panel and power station (never connected to house wiring) needs no permission.
- No plug-in solar bill has been filed yet; the nearby states that passed laws in 2026 are the template to expect.
The rules in detail
Montana has no statute specific to plug-in solar. Average residential electricity price: 14.99¢ per kWh (EIA, July 2026).
Your utility's rules in Montana
No utility in Montana publishes a rule that specifically allows or bans outlet-connected generation, so the general interconnection agreement is what applies. Here is what the largest residential utilities say and require.
| Utility | Residential customers | Published position on plug-in kits |
|---|---|---|
| NorthWestern Energy | 328,127 | No specific statement; advises 'verifying the installer you select is using a licensed electrician'. source |
| Flathead Electric Cooperative | 63,317 | No specific statement. |
| Montana-Dakota Utilities | 19,616 | No specific statement. |
Interconnection terms for a sub-1.2 kW system
| Regulator | Montana Public Service Commission. |
|---|---|
| Governing rule | MCA 69-8-601 et seq. net metering; NWE interconnection agreement. |
| Smallest tier | <=50 kW net metering. |
| Application fee | Not stated (gap). |
| Electrician / permit | 2020 NEC; licensed electrician expected; homeowner permits allowed. |
| Export compensation | Retail kWh credit, reset to zero at annual settle-up. |
| Electrical code | 2020 NEC (eff. 6/10/2022; 2023 in process). |
- No sales tax; retail NEM survives with agreement.
- Biennial legislature: earliest bill January 2027.
State incentives
- No sales tax; state credit repealed 2022; property-tax exemption.
Who is pushing for a law
- Montana Renewable Energy Association
- MEIC
- NW Energy Coalition
Savings preview: 800 W kit in Montana
Adjust for your setup →≈ $134/year
Frequently asked questions
Is plug-in solar legal in Montana?
Montana has no plug-in solar law. Plugging a kit into an outlet falls under your utility's interconnection rules, which usually require approval.
Do I need a permit or electrician for plug-in solar in Montana?
Default. Check with your local building department before you plug in.
Do I have to tell my utility in Montana?
Default. Plugging in a grid-tied kit without following this can breach your service agreement.
What can an 800 W plug-in kit save in Montana?
Roughly 896 kWh and about $134 per year at Montana's average residential rate of 14.99¢/kWh, assuming a typical balcony or patio mount. See the calculator for your exact setup.