Missoula Energy Guide: Solar, Batteries, Backup Power, EV

In short: Which utility serves your Missoula home changes the answers. NorthWestern Energy averaged about 14.2¢ per kWh in 2024. Missoula Electric Cooperative was cheaper, about 10.5¢, but its members lost about 27 hours of power on average that year (EIA). Ice storms and cold waves are the county’s top-rated hazards, so backup deserves a serious look.

Below: what each utility’s rules mean for solar and batteries, how to plan for winter outages and smoky fire seasons, and who issues permits in the city and county. For statewide rules (net metering law, the DEQ solar loan, the property tax exemption), see our Montana energy guide.

Missoula at a glance

• Utilities: in Missoula County, EIA lists NorthWestern Energy, Missoula Electric Cooperative (MEC), Mission Valley Power and Ravalli County Electric Cooperative. Your bill shows which serves you.
• Price, 2024 average: NorthWestern about 14.2¢ per kWh; MEC about 10.5¢ (EIA-861, revenue divided by sales).
• Outages, 2024: MEC 1,606 minutes per member with major events and 506 without, about 3.6 interruptions a year. NorthWestern in Montana 233 and 118 (EIA-861; NorthWestern’s figure is statewide).
• Sun: 4.01 kWh per square meter per day in Missoula (NASA POWER, 2001–2020), from 1.2 in December to 7.3 in July. Our rough estimate: about 1,170 kWh a year per kW of panels.
• Top hazards: FEMA’s National Risk Index (December 2025) rates Missoula County “relatively high” for ice storms, cold waves and avalanches, and “relatively moderate” for winter weather, wildfire, lightning, landslides and earthquakes.
• Public charging: 57 public ports at 22 locations in Missoula (AFDC, October 2026).

Your utility and what it means

NorthWestern Energy credits surplus solar to future bills until your annual settle-up month (January, April, July or October, chosen on the application), when NorthWestern says Montana law resets any leftover credit to zero. The monthly service fee stays. NorthWestern pays no residential solar incentive, but its E+ rebates for August 2026 to June 2027 include $100 for a qualifying air purifier, useful on smoky summer days, $450 for a heat pump and $150 for engine block heater controls. See NorthWestern net metering.

Missoula Electric Cooperative sets its own net metering rules (from its solar page as archived in March 2026):

• Systems can be sized to cover up to 100% of your yearly use. Up to 10 kW (AC) needs approval from an MEC representative; 10 to 50 kW needs board approval; nothing above 50 kW.
• In a month when you make more than you use, the energy charge is $0 and the surplus goes into your Net Meter Bank for later.
• The monthly base charge stays, and a peak charge can apply if you use more than you generate during weekday peak hours (7 to 10 a.m. and 6 to 9 p.m.).

Ask MEC for its net metering policy and whether banked kWh expire before you sign. Mission Valley Power and Ravalli County Electric members should ask their own utility.

Backup power in Missoula

MEC’s 2024 numbers stand out: members averaged about 27 hours without power counting major events, and over 8 hours on ordinary days, with the average outage lasting more than 7 hours. One severe year can skew a single co-op’s figures, but numbers like these are a reason to plan. Ice storms and cold waves, the county’s top-rated hazards, bring outages when heat matters most. In fire season, NorthWestern can call a Public Safety Power Shutoff, and smoke can keep windows shut for days.

• Generator on a transfer switch: for multi-day winter outages, furnaces and well pumps. See generators and generator installation.
• Home battery: quiet backup; with solar it recharges on clear days. See home batteries.
• Portable power station: runs an air purifier, CPAP and phones indoors with no exhaust. See portable power stations.

Size it with the generator sizing tool or battery backup calculator, and read our backup power guide. Run a generator outdoors only, at least 20 feet from the house with the exhaust pointed away, and keep carbon monoxide alarms inside (CPSC). In fire season, set it on gravel or bare ground away from dry grass.

Solar in Missoula

By our rough estimate, a 6 kW system in Missoula makes about 7,000 kWh a year. If the credits are all used, that’s worth about $1,000 at NorthWestern’s 2024 average price, or about $740 at MEC’s lower price. December output is about a sixth of July’s, so summer surplus has to carry winter: watch NorthWestern’s settle-up month, and ask MEC about its bank. Snow on panels trims winter output further. These are estimates, not quotes.

Test your roof with the solar potential tool and solar savings calculator, and read solar installation, solar costs and how net metering works.

Home batteries

For NorthWestern customers, kWh-for-kWh credit means a battery is a backup purchase. For MEC members it can do two jobs: carry the house through outages, and supply the home during weekday peak hours so you don’t draw from the grid then, which is what triggers MEC’s peak charge. Ask MEC how the charge is calculated before counting on savings. Keep a lithium battery somewhere above freezing. See battery costs and battery installation.

EV charging

At 30 kWh per 100 miles and 2024 average prices, home charging costs about $4.25 per 100 miles on NorthWestern and $3.15 on MEC (our estimates). MEC members can avoid adding to the peak charge by charging outside 7 to 10 a.m. and 6 to 9 p.m. on weekdays. A Level 2 charger needs a 240-volt circuit and an electrical permit. See EV charger installation and the EV charging cost calculator.

Drive on another fuel? See every alternative fuel station in Missoula: hydrogen, propane, natural gas, E85 ethanol, biodiesel and renewable diesel.

Permits and inspections

• City of Missoula: certified by the state to issue building and electrical permits inside city limits.
• Missoula County: also certified for building and electrical permits in the county (see the state’s certified local governments list).
• Utility approval: NorthWestern or MEC must approve a grid-tied system before you switch it on.

Hire a licensed electrical contractor (license lookup on the state page), and check HOA rules on roof equipment and generators.

Cities we cover

• Missoula

Get help in Missoula

Tell us about your project and we will connect you with a licensed, independent installer who serves the Missoula area. It is free, there is no obligation, and only the installer you choose gets your details. Read how it works.

Missoula energy questions

How long were Missoula Electric Co-op outages in 2024?

EIA’s data show MEC members averaged 1,606 minutes without power in 2024 including major events, about 27 hours, and 506 minutes without them, across about 3.6 interruptions. NorthWestern’s statewide figures were 233 and 118 minutes. One year can be skewed by a single storm, but it’s a good reason to plan backup.

How big a solar system will Missoula Electric approve?

Up to 100% of your yearly use. Systems up to 10 kW (AC) are approved by MEC staff, 10 to 50 kW by the board, and nothing larger than 50 kW is allowed.

Can a battery lower my MEC bill?

Possibly. MEC’s peak charge applies when a net-metered member uses more than they generate during weekday peak hours (7 to 10 a.m. and 6 to 9 p.m.). A battery that covers those hours could help. Ask MEC for the current charge before you buy.

Who issues solar and electrical permits in Missoula?

Inside city limits, the City of Missoula; in the rest of the county, Missoula County. Both are certified by the state for electrical permits. Your installer normally files them, and your utility approves the connection separately.

Sources

EIA-861, 2024 (price = residential revenue ÷ sales; outages; service territory; net-metered systems); Missoula Electric Cooperative solar installations page (archived March 2026); NorthWestern Energy net metering, home solar and wildfire pages and E+ rebate form (August 2026 to June 2027); Montana Building Codes Bureau certified local governments list; NASA POWER, 2001–2020; FEMA National Risk Index, December 2025; AFDC station data; CPSC. Read October 2026 unless noted. Estimates are ours and labelled.