What’s the maximum size solar system you can install

December 24, 2019 | 5min read

There are no general limits on the maximum size solar system you can install. However, states and local utility companies may set limits on how much power they will allow you to generate. Additionally, there are physical limitations you need to consider such as how much space you have on your roof or on your land to install solar panels. 

Arizona maximum size solar system limit

The state of Arizona sets a maximum system size limit of 125% of the customer’s total connected load. Additionally, Arizona’s utility companies including the Salt River Project (SRP), Tuscon Electric Power (TEP), and Arizona Public Service (APS) each set their own limits.

APS limits

The amount of power APS will allow you to feed into the grid is based on how your system is connected to the grid. The most common way systems are connected is via a circuit breaker in the home’s main service panel. This type of connection is called a load side connection. APS sets the following limits based on service panel rating:

  • 200 Amp service = Maximum of 15 kilowatts
  • 400 Amp service = Maximum of 30 kilowatts
  • 600 Amp service = Maximum of 45 kilowatts
  • 800 Amp and above service = Maximum of 60 kilowatts

APS also charges a monthly fee of $0.93 per kilowatt DC power that your system is rated for. Thus a 10-kilowatt system will be charged a monthly fee of $9.30.

APS customers: Want a larger system? We can upgrade your main breaker!

SRP limits

The Salt River Project doesn’t set upper limits for the maximum size solar system you can install. However, the rate schedule that SRP uses limits how much you get paid for the excess energy you produce. If your system produces more power than you use, you will only receive $0.037 – $0.0633 per kilowatt-hour for that excess power. Thus you may find it best to produce only as much power as you use. SRP doesn’t charge a  monthly fee based on your solar system’s size as APS does.

TEP limits

Tucson Electric Power doesn’t set a maximum size for solar systems. Instead, as of December 2019, TEP currently pays customers a rate of $0.0964 per kilowatt-hour for excess energy generated by their systems. The rate TEP pays is revised annually,and  TEP is allowed to reduce that rate by up to 10 percent per year. The amount of compensation paid is set for 10 years at the quoted rate when the system was first installed. 

Tribal-based power utilities

Some utilities in Arizona, such as tribal-based utilities don’t pay anything for power fed into their grids. They simply allow you to feed your excess power to the grid.

California: Larger solar systems require higher fees

The state of California doesn’t set limits on the maximum size solar system you can install. However, if you decide to install a system of over 15 kilowatts, you will be subject to higher permitting fees. Government code 66015 dictates that if your system is 15 kilowatts or less, your permitting fee is $450. If your system is going to be larger than 15 kilowatts, then you must pay a $500 fee plus $15 per kilowatt for every kilowatt above 15 kilowatts.

San Diego Gas and Electric (SDG&E)

SDG&E does limit the size of your solar system. You are allowed to generate 125% of your average power usage.

Colorado maximum size solar system limit

Colorado’s largest electricity provider, Excel energy, allows you to generate up to 120% of your total usage from the previous 12 months. If 12 months of information isn’t available, size limits will be determined from available usage data if there is a minimum of 4 months of data. If this date is not4 four months aren’t available, then Xcel energy will estimate usage.

EV size increase

If you recently purchased an EV, you are allowed to add up to 250 kilowatt-hours per month to your system’s size. If you’ve owned your EV for more than 4 months, then you can’t add anything to your maximum allowed system size. Your EV’s usage is already part of your home’s calculated energy usage.

Illinois net metering cap

According to the Illinois Attorney General’s website: “Under Illinois rules, eligible renewable generators of 40 kW or less receive a one-to-one retail rate credit. These customers will be compensated for excess electricity generated by their renewable energy systems at the same rate that they pay when buying electricity from their utility. These credits will be carried over month-to-month, with the annual period running from May to April, or November to October, at the customer’s discretion.”

Nevada maximum size solar system limit

Nevada requires that the solar system be no larger than the highest monthly energy usage recorded at the home in the last 24 months. Systems can be less than that maximum, but they can’t be sized to generate more energy than is estimated to be consumed in a year based on the customer’s prior usage.

Utah net billing

The maximum solar system size in Utah is dictated by the state’s utilities. The state’s largest utility, Rocky Mountain Power, will pay customers at the rate of $ 0.92 per kilowatt-hour for electricity from their solar systems. This compensation plan is in place until the amount of energy on the grid from solar hits 170 megawatts. After that target is reached, a finalized rate structure will be put in place. That rate structure hasn’t been determined as of December 2019.

Texas: Maximum size solar system depends on the utility company you select

Texas has a deregulated energy market with 45 utility companies to choose from. Each of those companies may or may not have a policy on what the maximum size solar system they will allow you to install. Your best bet is to look up retail electric providers in your area and find out what those providers will allow.

Freedom Forever can help you find the perfect solar system size for you

The size of the system you install should fit your needs perfectly. That’s where Freedom Forever’s family of independent authorized dealers truly shine. They are experts on going solar. They have experience in how state laws and utility companies can affect the sizing of a solar system. They will be able to help you make a smart decision.

Ready to go solar? Call Freedom Forever at  800-685-1850 or click below to get a quote.