In short: Castle Rock has about 83,200 people and sits in Douglas County. Public Service Co of Colorado, CORE Electric Cooperative and Mountain View Elec Assn, Inc serves different parts of Douglas County, so your utility depends on your address; their 2024 home averages range from 15.04¢ to 15.52¢ per kWh (EIA). FEMA rates Douglas County lightning “very high”. Rooftop solar here makes roughly 1,420 kWh a year per kW of panels by our estimate, which is good for solar.
This page covers what is local to Castle Rock: its utility, outage records, sunshine, weather risks and charging. Statewide rules such as net metering, incentives and electrician licensing are in our Colorado energy guide and the wider area is covered in the Denver guide.
Castle Rock at a glance
- Place: Castle Rock, Douglas County, Colorado; about 83,213 residents (Census Bureau estimate, July 2024).
- Utility: Public Service Co of Colorado (investor-owned). Homes paid an average 15.05¢ per kWh in 2024 (EIA-861); the average customer lost 158 minutes of power on normal days and 352 counting major storms, with 1.4 interruptions a year (utility-wide, not just Castle Rock).
- Utility: CORE Electric Cooperative (member-owned cooperative). Homes paid an average 15.04¢ per kWh in 2024 (EIA-861); the average customer lost 74 minutes of power on normal days and 212 counting major storms, with 0.8 interruptions a year (utility-wide, not just Castle Rock).
- Utility: Mountain View Elec Assn, Inc (member-owned cooperative). Homes paid an average 15.52¢ per kWh in 2024 (EIA-861); the average customer lost 42 minutes of power on normal days and 56 counting major storms, with 0.5 interruptions a year (utility-wide, not just Castle Rock).
- Sun: 4.85 kWh per square meter per day on average, from 2.29 in December to 7.22 in June (NASA POWER). Our rough estimate: about 1,420 kWh a year per kW of panels.
- Climate: about 570 cooling degree-days and 6,270 heating degree-days a year (base 65°F, NASA POWER), so heating is the big load.
- Top hazards in Douglas County: lightning “very high”, winter weather “very high” and hail “relatively high” (FEMA National Risk Index; overall county risk rated “relatively moderate”).
- Public charging: 64 ports at 20 locations in Castle Rock, 28 of them DC fast (AFDC, October 20, 2026).
Your utility and what it means
Public Service Co of Colorado is an investor-owned utility and served about 1,365,053 home customers in 2024; its 15.05¢ average was below the 17.0¢ statewide average for July 2026. CORE Electric Cooperative is a member-owned cooperative utility and served about 165,067 home customers in 2024; its 15.04¢ average was below the 17.0¢ statewide average for July 2026. Mountain View Elec Assn, Inc is a member-owned cooperative utility and served about 59,789 home customers in 2024; its 15.52¢ average was below the 17.0¢ 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, Public Service Co of Colorado reported 158 minutes per customer without major storms in 2024, more than the statewide figure of 119 (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 Colorado guide and then ask your utility for its current interconnection steps before you sign anything.
Backup power in Castle Rock
- Lightning (very high): Lightning causes short outages and damages electronics. Surge protection and a battery that switches over automatically protect the things you care about.
- Winter weather (very high): Winter storms and cold snaps combine outages with heating demand. Plan for the furnace blower or heat pump, not just lights, and keep a fuel supply you can reach in snow.
- Heating load: a winter outage can stop a furnace blower, boiler pump or heat pump. List what your heat needs to run before choosing a generator or battery.
- 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 Castle Rock
By our rough estimate each kW of panels makes about 1,420 kWh a year in Castle Rock (NASA sunshine data times 365 days times 0.80 for system losses). Valued at Public Service Co of Colorado’s 2024 average of 15.05¢, that is about $214 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 7.22 and December the dimmest at 2.29, a 3.2-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. Castle Rock has 64 public charging ports in the federal station list including 28 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 Castle Rock: 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 Castle Rock building or permitting department, or from Douglas County if you live outside city limits, and often a utility interconnection approval. We have not verified a local permit page for Castle Rock, so check the city and county websites or ask your electrician, who will know the process. Hire only a licensed electrician or installer; the Colorado guide lists the state licensing rules.
Nearby guides
More local guides: Denver energy guide, Centennial, Aurora, Lakewood and Commerce City, or the whole Colorado energy guide.
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Castle Rock energy FAQ
Who is my electric company in Castle Rock?
Public Service Co of Colorado, CORE Electric Cooperative and Mountain View Elec Assn, Inc all serve parts of Douglas County. Which one serves you depends on your street, so check the top of your bill. Their 2024 home price averages differ (Public Service Co of Colorado 15.05¢, CORE Electric Cooperative 15.04¢, Mountain View Elec Assn, Inc 15.52¢) so it matters for solar math.
How much power will solar make in Castle Rock?
About 1,420 kWh a year per kW of panels by our estimate, so a 6 kW system would make roughly 8,520 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 winter weather in Douglas 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.
Will a home battery keep my heat on in an outage?
It can keep a furnace blower, boiler pump or a heat pump running for a while, but long cold outages drain a battery fast without solar to recharge it. Pair it with a generator or wood or propane heat if outages here run for days.
Do I need a permit for solar or a generator in Castle Rock?
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.