What is a solar panel system?

Solar panel systems (or solar energy systems) use Photovoltaic (PV) cells to convert sunlight into direct current (DC) electricity. Solar panel cells are made from silicon and were originally developed to power spacecraft and space stations. The cells are wired together in panels that typically measure about 4 feet by 1 foot by 1.5 inches deep. A group of solar panels mounted on a frame is called a solar panel solar panel array.

To provide electricity reliably and safely, solar panel system components typically include an inverter, wiring and optional battery storage and charge controller. Most solar panel systems convert the DC electricity that is produced by the solar panels into the common household form of electricity—alternating current (AC)—by using an inverter. AC electricity can then be used to power your appliances directly, or feed back to an electric utility's grid. The DC electricity can also be stored directly in batteries for later use. In this case, to prevent overcharging or discharging of the batteries, a charge controller is used.

What is the environmental impact if I use solar power at home?
Solar panels have received attention from researchers, businesses and homeowners because, unlike traditional power generation sources, these technologies produce electricity using a renewable source—the sun—without creating noise, emitting pollutants that cause climate change such as greenhouse gases, smog, acid rain, or water resource pollution. Even when the emissions related to solar cell manufacturing are counted, solar panels produce less than 15% of the carbon dioxide from a conventional coal-fired power plant.

As a general rule of thumb, studies indicate that the typical California home using solar power has an environmental impact of removing two cars from the road.  Over 25 years, you will have avoided producing more than 500 tons of greenhouse gas emissions. Using solar electricity to power a million homes would reduce greenhouse gas emissions by 4.3 million tons per year, the equivalent of removing 850,000 cars from the road (Source: EPA).

Does a solar panel system replace an electric utility?
Solar panel systems are typically used as either stand-alone systems or grid-connected systems. The role of solar panels in these two types of systems is very different, and the design decisions and performance requirements are very different as well.

Stand-alone solar panel systems generate all of the on-site electricity needs of a home. Therefore, they are not connected to any electric utility. Stand-alone systems can provide AC or DC electricity, and typically include batteries to store electricity for use when the sun is not shining. Stand-alone systems are often cost-effective when installed in remote areas where access by electric utilities is difficult and expensive.

Grid-connected solar panel systems are typically sized to meet at least 50% of a home's electrical load. These systems are not always sized to meet all of the electricity loads of a house because of the higher up-front costs associated with purchasing a larger system. Solar panel systems can be easily integrated with a utility's electrical grid to provide clean, renewable electricity for homeowners, while still ensuring continuous power supply from your regular utility.

What are the benefits of having a solar panel system?

How much does a solar panel system cost? What Rebates and Incentives are available?

The cost of a solar panel system depends on the system's size and the types of components. The table below lists average equipment costs and incentives for grid-connected solar panel systems without a battery backup in the US (Source: California Energy Commission).

The cost of a solar panel system depends on the system's size and the types of components. The table below lists average equipment costs and incentives for grid-connected solar panel systems without a battery backup in the US (Source: California Energy Commission).

To see solar power state rebate information, choose the link for your state.

The actual cost of a solar panel system will depend on whether the system is integrated into the roof-top material or mounted on top of an existing roof, the system configuration (i.e. standardized systems offered by some solar panel retailers generally cost less), equipment options, installation costs, and the solar panel manufacturer.

What size system do I need?

In California, the average residential customer uses 6,500 kilowatt-hours (kWh) of electricity per year (California Energy Commission). The following table provides simple estimates of solar panel system costs, size and savings.

Please note: These are estimates only. There are many factors that may affect costs and savings. *25-year cost includes 2.5% annual electricity price inflation.

Can I get credit for producing my own electricity?
Yes. The energy that is produced by a solar panel system will first serve a home's electrical load. Then, if the solar panel system produces more electricity than the home needs at any given time, your utility credits the excess electricity at the same price you would pay for electricity from the utility - in effect turning the electrical meter backwards. This is called "Net Metering," and the credit will appear on the monthly utility bill. Should the home need more energy than the solar panel system is producing at any given time, the customer can be assured that the utility will provide the electricity that the home needs. Often, homeowners find that they receive credits during expensive peak daytime hours, and then use more utility power during less expensive evening hours.

What is the lifespan of a solar panel system?
Solar panel systems last a long time depending on the amount of active use, or the amount of sunshine converted into electricity by the solar panels. Most systems are only in use for 6 to 8 hours per day. Manufacturers will usually provide from 10 to 20 year warranties for the solar panels, and a 5- to 10-year warranty on the balance of system components. Solar panels have been reported to last 30 to 40 years.

Solar panel systems last a long time depending on the amount of active use, or the amount of sunshine converted into electricity by the solar panels. Most systems are only in use for 6 to 8 hours per day. Manufacturers will usually provide from 10 to 20 year warranties for the solar panels, and a 5- to 10-year warranty on the balance of system components. Solar panels have been reported to last 30 to 40 years.

What is involved in maintaining and operating a solar panel system?
Without any moving parts, maintaining a solar panel system is relatively simple. For grid-connected systems, minimal maintenance is required, including keeping the panels free of any debris such as fallen leaves, bird droppings, etc. For stand-alone systems, the batteries usually require the most maintenance. Your solar panel system retailer will provide instructions about simple maintenance that you can do yourself.

Will a solar panel system require additional insurance?
Typically, homeowners will be required by the utility company to provide proof of insurance coverage for their system. However, most standard homeowner insurance policies provide adequate insurance protection and meet the minimum requirements stated in your utility’s interconnection agreement.