Anders Alexander has worked in solar since 2013, from selling residential systems and directing installer sales teams to managing solar analysis software at EagleView and partnering on clean energy financing. He serves on the boards of the Washington Solar Energy Industries Association and Solar Washington.
Montana grew its rooftop solar 42.9% in a single year, the second-fastest rate among the states with no free-solar providers at all, and by far the fastest on a base of any real size. It did that with no leasing companies, no state rebate and no state tax credit. What Montana has instead is full retail netting, and one decision you make on a form that most homeowners never realize they are making.
Growing Fast Without Anyone Selling It Free
Free solar means a lease or a power purchase agreement, under which a company owns the system on your roof. Per the Database of State Incentives for Renewables and Efficiency, Montana is one of 17 states with no current residential third-party ownership offerings, sitting at 68 MW of installed residential capacity.
The fine print changes by state; our no-cost solar programs in every state covers all of them.
Only South Dakota grew faster inside that group, and it did so from 3.9 MW, where a handful of installations moves the percentage. Montana’s 42.9% came off a base seventeen times larger, which makes it some of the most convincing evidence anywhere in the country that a rooftop market can grow briskly with no no-money-down product in it at all.
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Full Retail Netting Is Why
Under Title 69, chapter 8, part 6 of the Montana Code, the utility measures net electricity produced or consumed each billing period, and where you generate more than you use you are credited for the excess in kilowatt-hours, appearing on the following month’s bill. Credits held in kilowatt-hours rather than dollars is the version worth having: a unit banked in July buys a unit in January regardless of what happened to rates in between.
Against Montana’s statewide average residential rate near 13.2¢, that is full value on every exported unit, which puts Montana ahead of most states and explains a good deal of the growth. Residential systems up to 50 kW qualify, and the Public Service Commission rejected NorthWestern Energy’s attempt to end retail netting in December 2019 with no successor tariff since.
The Date on the Interconnection Form
One provision decides how much of your generation you actually keep, and it is the rare decision that costs nothing to get right. The statute lets the customer-generator designate January 1, April 1, July 1 or October 1 as the start of a 12-month billing period. At the end of it, any unused kilowatt-hour credit is granted to the utility, without any compensation to you.
Montana generates in summer and heats in winter, so the question is simply which date leaves your balance closest to empty when the clock runs out.
Start date | Your year ends | What your balance looks like then |
|---|---|---|
April 1 | March 31 | Lowest. A summer of banking has just been spent across the winter. |
January 1 | December 31 | Partly drawn down, with the coldest months still ahead. |
July 1 | June 30 | Rising again after spring, so some of the new bank is surrendered. |
October 1 | September 30 | Highest. An entire summer surrendered on the eve of winter. |
April 1 and October 1 are the same statute, the same system and the same roof, separated by a choice made once on a form. Ask your installer which date they are putting down, and ask before the interconnection paperwork is filed rather than after. No leasing company would have made this choice for you, and no leasing company can take it away.
It also caps what a sensible system looks like. Generation above your annual consumption is handed to the utility for nothing at the true-up, so the credit bank has a ceiling and that ceiling is your own yearly usage.
What the State Actually Gives a Buyer
Montana no longer runs a state income tax credit for residential solar. The Alternative Energy System Credit, once worth up to $500 per taxpayer on Form ENRG-B, was repealed by Senate Bill 399 in 2021 and cannot be claimed for a new installation. If a quote or an older guide still counts it, the math is a few years out of date. What survives is the property tax side.
$20,000 of the assessed value attributable to the system is exempt from property tax on a single-family home for ten years after installation. It does not arrive as a check, and it goes to whoever owns the system, which in Montana is going to be you.
The federal residential credit is $0 for purchased systems whose installation is completed after December 31, 2025 under Public Law 119-21. Section 48E survives for businesses that own systems, on current terms only for projects in service by the end of 2027 or that began construction by July 4, 2026, and it requires the lease or power purchase arrangements Montana has no providers for.
You Likely Will Not Qualify If
- You are answering a national free solar advertisement. Montana is among the 17 states with no current residential third-party ownership providers. If one of those ads does reach you, expect the contract to raise your payment 2 to 3% every year on its escalator for the full 20 to 25 year term.
- Your power comes from a rural electric cooperative. Montana’s net metering statute governs the regulated utilities; cooperatives set their own terms and several are less generous.
- You are planning to bank credits beyond a year. Everything unused at your designated annual true-up is granted to the utility without compensation.
- You expect the old $500 state credit. The Alternative Energy System Credit was repealed by Senate Bill 399 for new installations; no state income tax credit remains.
- You are counting on the 30% federal credit. Section 25D is $0 for purchased systems from January 1, 2026.
Two Levers, Both Set Before Installation
Montana hands a homeowner two decisions that no financing product would improve. Size the array to annual consumption rather than above it, because anything above it is surrendered. Then choose the true-up date that puts the surrender at the moment your bank is naturally lowest, which in a state that heats in winter and generates in summer means the spring.
Get those right and Montana’s retail netting is among the better arrangements left in the country, which is presumably what 42.9% growth in a year already reflects. Our Montana incentives guide covers the statute and the exemptions, and the Montana installer list covers who does the work.
Montana Solar FAQs
No company currently offers them. Montana is among the 17 states with no current residential third-party ownership providers. It nonetheless grew its rooftop solar 42.9% in a year on a 68 MW base, the second-fastest rate in that group and the fastest on a base of any real size, all of it purchased rather than leased.
Yes, you choose. The statute lets you designate January 1, April 1, July 1 or October 1 as the start of your 12-month billing period, and any unused kilowatt-hour credit at the end of it is granted to the utility without compensation. April 1 is usually best, because your year then ends on March 31 with the summer bank already spent across winter. October 1 is the worst, surrendering a whole summer just before you need it.
Yes. The utility measures net electricity each billing period and credits excess generation in kilowatt-hours on the following bill, which against a residential rate near 13.2¢ is full value on every exported unit. Residential systems up to 50 kW qualify, and the Public Service Commission rejected NorthWestern Energy’s attempt to end retail netting in December 2019 with no successor tariff since.
A property tax exemption covering $20,000 of assessed value on a single-family home for ten years. The old Alternative Energy System Credit of up to $500 was repealed by Senate Bill 399 and cannot be claimed for a new installation, so no state income tax credit remains. The exemption follows whoever owns the system, which in Montana means you, since no third-party providers operate here.
No larger than your annual consumption. Because unused kilowatt-hour credits are surrendered at your annual true-up without payment, generation above what the house uses in a year is given to the utility for nothing. The credit bank effectively has a ceiling and that ceiling is your own yearly usage, which is a firmer sizing limit than any sales conversation will offer.
The true-up date is set before installation, not after. Enter your ZIP code to see who serves your address.
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References & Research Sources
The netting mechanics, exemption and market figures above come from the records below. Capacity figures are 2024 data. Sources accessed between June 10 and August 20, 2026.
- pv magazine USA. States without residential solar third-party ownership may become holes in the market after 2025. Analysis drawing on DSIRE and US Energy Information Administration data: the 17-state count including Montana, Montana’s 68.0 MW installed residential base at the end of 2024 with 42.9% twelve-month growth, and South Dakota’s 58.5% growth from a 3.9 MW base used in the comparison. Dated July 22, 2025. Accessed August 17, 2026.
- Montana Legislature. Montana Code Annotated 69-8-603. Net electricity measured each billing period, excess kilowatt-hours credited to the following bill, the customer’s designation of January 1, April 1, July 1 or October 1 as the start of a 12-month billing period, and the grant of unused credit to the utility without compensation; MCA 69-8-103 carries the 50 kW limit, and the Public Service Commission rejected NorthWestern Energy’s proposal to end retail net metering in December 2019. Accessed August 17, 2026.
- Montana Department of Revenue. Alternative Energy System Credit, Form ENRG-B. The record of the former up-to-$500 credit, repealed by Senate Bill 399 in 2021 and not claimable for new installations; the $20,000 renewable energy property tax exemption for ten years stands. Repeal confirmed against the Department’s own guidance August 20, 2026.
- US Energy Information Administration. Electric Power Monthly, Table 5.6.A: Average Price of Electricity to Ultimate Customers. The Montana statewide average residential rate of 13.2¢ per kWh used on this page as labeled context. Accessed August 17, 2026.
- Internal Revenue Service. One, Big, Beautiful Bill provisions. The Public Law 119-21 termination of Section 25D for purchased systems whose installation is completed after December 31, 2025, and the availability of Section 48E to business owners of residential systems under current deadlines. Accessed August 17, 2026.
