Solar FAQs


Solar energy has many cost benefits. But there are many things you’ll need to consider before installing a solar electric system on your home or business. Consider the following common questions:

What is a solar electric system?

  • Solar electric systems, also referred to as solar photovoltaic (PV), converts sunlight into electricity and are most often mounted on your roof. They provide your home or business electricity any time the sun is shining. Solar electricity is a renewable source of energy!

Do I still have electricity when there is no sunlight?

  • Yes, if you are interconnected to CPS Energy's electrical grid, we are providing you electricity for your home or business when the solar electric system is not generating electricity.

Can CPS Energy recommend a solar contractor?

  • As a municipal utility, CPS Energy cannot provide referrals to individual contractors. However, we do provide a list of registered installers who have obtained the North American Board of Certified Energy Practitioners (NAPCEP) certification for solar installations or who pledged to acquire this certification within two years. Program guidelines call for the use of installers who have registered with CPS Energy.

How much electricity will a 1 kW, 2 kW or 3 kW system produce?

  • Typically, solar electric systems produce 1,600 kilowatt-hours (kWh) per year per kilowatt (kW). This means that a 1 kW system will produce 133 kWh/month, a 2 kW system will produce 266 kWh/month, and a 3 kW system will produce 400 kWh/month. Systems will vary in the level of output based on the solar panels and inverter that you select. It is recommended to contact a local solar contractor for more information regarding solar electric system output.

Do solar attic fans qualify for a solar rebate?

  • No, solar attic fans do not qualify. The solar rebates are intended only for grid-connected systems.

How do I know what size system to purchase?

  • The size of the system you choose will depend on the amount of money you want to invest and the amount of electricity you want to produce. Review your old statement to help determine how much electricity your home typically uses. Ensure that the installation location is large enough, is oriented properly and has minimal shading for the size system you choose.

    As a rule, the cost per kilowatt-hour goes down as the size of your system increases. Work with your Solar Installer to help determine the goals of your system and how much you are willing to invest. The average home in San Antonio uses approximately 1,200 kWh per month.

What happens at night?

  • Since sunlight is required for solar energy systems your system will not produce electricity at night. Unless you purchase a system with a battery backup, CPS Energy will supply your energy needs at night.

Do systems with battery backup qualify for a rebate?

  • Yes. However, there are no incentives available for the battery portion of the system. The rebate amount is calculated based on the expected performance of the modules and the efficiency of the inverter.

Do the modules need to be mounted on my roof?

  • PV modules are often mounted on the roof, but they can also be mounted on the ground. Ground mounted systems are a better choice if the house/roof is shaded, or if dormers or other obstructions limit available roof space.

If I do expand the size of my system, can I apply for another rebate?

  • Yes, applications for increasing the size of a system, are subject to the Application Procedures, Terms & Conditions, Rebate Tiers, and other solar rebate program criteria in place at the time of acceptance. If I build a large enough PV project, can I sell the excess energy to my neighbors?

CPS Energy has not opted into competition, and is not subjected to some of the same rulings as “electric utilities” that are competitive by state law. Therefore, excess energy, from any source, cannot be sold by one individual to another individual but can only be sold back to CPS Energy.

What happens during an electric outage?

  • For any type of electric outage, only solar energy systems with battery backup will continue to have power. Systems without battery backup, by law and CPS Energy standards, must shut down until the outage has been restored.

Who will help me apply for the CPS Energy Solar Initiative Rebate?

  • Your chosen CPS Energy Participating Solar Installer will assist in the rebate application process to help secure these rebates for you.

How long does it take to install a PV system?

  • The typical installation time for a residential system is from 2 to 5 days. Systems that are mounted on the ground or systems with batteries are more complex, and might take longer. Most of the installation time is spent on the outside of your house, so there should be little disturbance to you. The installation of commercial systems may take several weeks to over a month to install, depending upon size and type of installation.

Why are the interconnection requirements different in San Antonio than in other part of Texas?

  • CPS Energy does not fall into the definition of “electric utility” as defined by the Public Utility Commission of Texas (PUCT). As a “municipal utility or corporation” that has not opted into competition, CPS Energy is not subjected to some of the same rulings as “electric utilities” that are competitive by state law. CPS Energy offers interconnection means and methods that have been determined to be safe and reliable for all parties involved.

How durable is a solar energy system?

  • Solar energy system modules must pass a set of standard test for durability. They are built to withstand winds of up to 125 miles per hour and 1-inch hail.

Can I add battery backup at a later date?

  • Yes. If you start with a system that has battery backup, it's easy to add more. However, if you start with a system that does not have battery backup, it may be rather expensive to add later as those types of systems require a different type of inverter.

Do I need approval from my homeowners' association?

  • Yes. Check with your homeowners association first. If there are covenants and/or restrictions in your neighborhood regarding solar energy systems, you cannot receive a rebate. If your homeowners association is considering allowing such systems and would like more information, please have them contact CPS Energy.

Which type of modules or inverter should I choose?

  • Many different types of modules and inverters are available. Consult with your CPS Energy Solar Installer to determine which type of module and inverter will best meet your goals. For the purposes of the CPS Energy Solar Initiative rebate program, all equipment chosen must be new and listed on the California Energy Commission list of approved modules and inverters. Related Topic: Consumer Energy Center

Can I add to the size of my solar energy system later?

  • Yes, CPS Energy will allow for existing system owners to increase or add on to their existing system.

What is the typical warranty on a solar energy system?

  • Most solar energy system modules will carry a 20-30 year warranty and the inverter typically carries a 5-year warranty. Refer to the Solar Rebate Program Terms & Conditions for rebate requirements.

Where do I purchase a solar energy system?

  • Only solar installers registered with CPS Energy can be used to install your solar energy system. For the best price, CPS Energy encourages that you get more than one quote.

Do solar energy systems require maintenance?

  • For the most part, both solar electric and solar water heating systems are passive systems. However, to keep them working at optimal performance it is recommended the panels are kept clear of dust and debris - this can be accomplished by taking a hose and spraying down the panels. CPS Energy recommends consulting with your installer or the manufacturer regarding the maintenance of your solar energy systems.