In short: St. Charles has about 72,500 people and sits in St. Charles County. Union Electric Co and Cuivre River Electric Coop Inc serves different parts of St. Charles County, so your utility depends on your address; their 2024 home averages range from 11.07¢ to 12.56¢ per kWh (EIA). FEMA rates St. Charles County strong winds “very high”. Rooftop solar here makes roughly 1,220 kWh a year per kW of panels by our estimate, which is about average for the U.S..
This page covers what is local to St. Charles: its utility, outage records, sunshine, weather risks and charging. Statewide rules such as net metering, incentives and electrician licensing are in our Missouri energy guide and the wider area is covered in the St. Louis guide.
St. Charles at a glance
- Place: St. Charles, St. Charles County, Missouri; about 72,458 residents (Census Bureau estimate, July 2024).
- Utility: Union Electric Co (investor-owned). Homes paid an average 12.56¢ per kWh in 2024 (EIA-861); the average customer lost 94 minutes of power on normal days and 148 counting major storms, with 0.7 interruptions a year (utility-wide, not just St. Charles).
- Utility: Cuivre River Electric Coop Inc (member-owned cooperative). Homes paid an average 11.07¢ per kWh in 2024 (EIA-861); the average customer lost 133 minutes of power on normal days, with 1.3 interruptions a year (utility-wide, not just St. Charles).
- Sun: 4.17 kWh per square meter per day on average, from 1.81 in December to 6.42 in June (NASA POWER). Our rough estimate: about 1,220 kWh a year per kW of panels.
- Climate: about 1,400 cooling degree-days and 5,010 heating degree-days a year (base 65°F, NASA POWER), so heating and cooling both matter.
- Top hazards in St. Charles County: strong winds “very high”, hail “relatively high” and tornadoes “relatively high” (FEMA National Risk Index; overall county risk rated “relatively moderate”).
- Public charging: 21 ports at 3 locations in St. Charles, 21 of them DC fast (AFDC, October 20, 2026).
Your utility and what it means
Union Electric Co is an investor-owned utility and served about 1,095,619 home customers in 2024; its 12.56¢ average was below the 16.09¢ statewide average for July 2026. Cuivre River Electric Coop Inc is a member-owned cooperative utility and served about 72,974 home customers in 2024; its 11.07¢ average was below the 16.09¢ statewide average for July 2026. Those are utility-wide averages, not a quote for your address; your own bill is the real number.
For reliability, Cuivre River Electric Coop Inc reported 133 minutes per customer without major storms in 2024, more than the statewide figure of 106 (EIA-861). Utility-wide numbers hide a lot: a home at the end of a long rural line usually has more outages than the average.
Net metering, export rates and incentives are set at state level and by each utility. Start with the Missouri guide and then ask your utility for its current interconnection steps before you sign anything.
Backup power in St. Charles
- Strong winds (very high): High winds knock out lines on ordinary days. A battery or portable power station handles the common short outages; add a generator for multi-day repairs.
- Hail (relatively high): Hail is hard on rooftop solar; ask installers about impact-rated panels and your insurer about coverage.
- Short outages: a portable power station covers phones, Wi-Fi, a CPAP and lights; a home battery switches over automatically.
Size your setup with the generator sizing tool and the battery backup calculator, and compare options in backup power. Generator safety (CPSC): outdoors only, at least 20 feet from the house, exhaust away from doors and windows, never in a garage, and battery-powered carbon monoxide alarms inside. A licensed electrician should install any transfer switch, with a permit; see generator installation.
Solar in St. Charles
By our rough estimate each kW of panels makes about 1,220 kWh a year in St. Charles (NASA sunshine data times 365 days times 0.80 for system losses). Valued at Union Electric Co’s 2024 average of 12.56¢, that is about $153 a year per kW if all of it offsets your own use (an estimate, not a promise). Production swings with the seasons: June is the sunniest month at 6.42 and December the dimmest at 1.81, a 3.5-to-1 gap, so a battery or a bigger system helps in winter.
Check your own roof with the solar potential tool, see solar costs and net metering vs net billing, and read the steps in solar installation. Hail and storm exposure are worth raising with installers and your insurer.
Batteries and EV charging
A home battery earns its place when outages are frequent, when your utility pays little for exported solar, or when evening prices are high; compare in home batteries and battery costs. St. Charles has 21 public charging ports in the federal station list including 21 DC fast, but home charging is cheaper and easier: see the EV charging cost calculator and EV charger installation.
Drive on another fuel? See every alternative fuel station in St. Charles: hydrogen, propane, natural gas, E85 ethanol, biodiesel and renewable diesel.
Permits and inspections
Solar, generator transfer switches and EV chargers normally need an electrical permit from the St. Charles building or permitting department, or from St. Charles County if you live outside city limits, and often a utility interconnection approval. We have not verified a local permit page for St. Charles, so check the city and county websites or ask your electrician, who will know the process. Hire only a licensed electrician or installer; the Missouri guide lists the state licensing rules.
Nearby guides
More local guides: St. Louis energy guide, St. Peters, Chesterfield, Florissant and O’Fallon, or the whole Missouri energy guide.
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St. Charles energy FAQ
Who is my electric company in St. Charles?
Union Electric Co and Cuivre River Electric Coop Inc both serve parts of St. Charles County. Which one serves you depends on your street, so check the top of your bill. Their 2024 home price averages differ (Union Electric Co 12.56¢, Cuivre River Electric Coop Inc 11.07¢) so it matters for solar math.
How much power will solar make in St. Charles?
About 1,220 kWh a year per kW of panels by our estimate, so a 6 kW system would make roughly 7,320 kWh. Shade, roof direction and tilt change this; run your address through the solar potential tool for a better number.
Is a generator or a battery better for strong winds in St. Charles County?
It depends how long the outage lasts. A battery is quiet, automatic and good for short outages and for pairing with solar; a standby generator keeps going as long as it has fuel, which suits multi-day events. Many homes use a battery for everyday outages and add a generator for the rare long one.
Do I need a permit for solar or a generator in St. Charles?
Almost always an electrical permit for a transfer switch, solar or an EV charger, issued by the city or county where you live. Your licensed electrician or installer normally pulls it. Never connect a generator to your house wiring without a transfer switch.
Sources: EIA Form 861 (2024) for utility prices and outages; NASA POWER climatology (2001 to 2025) for sun and degree-days; FEMA National Risk Index for county hazards; AFDC station locator for public charging; Census Bureau for population. Estimates are ours and are not promises; see our editorial policy. Prices and programs change, so check each program page.