Frequently Asked Questions

Shading, roof orientation, aesthetic concerns, and the amount of space on your roof and the quality of your roof are all factors that need to be considered. You’ll want to install a solar electric system in a location that is free from shading, ideally on a roof with plenty of southern or western exposure to the sun.

Luminalt will take these factors into consideration when providing you with a proposal of a system size, the system’s estimated performance, installation cost and return on investment.

Shading can have a significant impact on your system’s production. A fairly small amount of shade can affect the production of the cells within that shaded panel (similar to how a kink in a hose slows down the flow through the rest of the hose). Ideally, you should have unobstructed sun from 9am to 3pm.

Although all warranties are different, most solar panels are guaranteed to produce electricity for a minimum of 25 years. A well-constructed system may produce electricity for considerably longer.

The life of your roof is a consideration. If your roof is getting towards the end of its life, consider reroofing.

A good time to get quotes for a solar system is when you are looking to reroof. Your solar installer and roofer can work together to waterproof the solar mounting points on your roof so they are included with your roof warranty.

When you go solar, you must go on a time of use (TOU) rate schedule. PG&E offers TOU rates for which it charges more for electricity during peak hours on weekday afternoons, and less for electricity during off-peak hours. When you are on a TOU rate, the electricity your solar system generates and feeds into the grid during peak times receives a credit at the higher rates. If you use most of your electricity during off-peak hours, you then draw against those credits at the lower rates, allowing you to use more electricity than your system generated because you are using it at times when the rates are cheaper. Investigate different rate schedules to determine which is best for you. A solar contractor can help you determine which rate schedule is best for your electricity usage patterns, and which can provide the best return on investment for your solar system.

A solar electric system tied to the electrical grid feeds electricity into the grid when the system generates more electricity than you use and draws electricity from the grid other times when you are using more electricity than your system is producing, such as after dark. The clean electricity your solar system generates first powers your home and then sends excess electricity back to the grid. PG&E customers receive a retail-priced credit for the excess electricity their systems produces, which you can apply to your electricity bill. This is called “net energy metering” or NEM. If your utility is a municipality or you are part of a CCA group, the rules may be different.

We ask you to provide interval data information through Utility API. Utility API is a service that provides the data directly. Alternatively, you can download Green Button directly from your online PG&E account. Interval data provides us with data that is detailed enough for us to compare your specific usage patterns against the estimated electricity generation of a solar system designed for your home. Interval data allows us to analyze different TOU rates to find the best fit and return on investment for you.

– Charges for the energy used from the electrical grid (when your solar isn’t generating as much electricity as you are using, for example, at night)
– Bill credits for excess energy generated from your solar system and sent to the grid (when more solar energy is generated than needed during the day)

Bill credits are calculated at predetermined rates set by the CPUC according to when the solar system is exporting energy to the grid throughout the year, and average roughly $0.03/kWh – $0.04/kWh.

Homeowners who install a solar system within the first five years of the new Solar Billing Plan will receive additional credit for excess solar energy exported to the grid. The assigned credit value will be locked in for homeowners and continue for 9 years, and averages roughly $0.02/kWh – $0.03/kWh. The additional credits will not be available to homeowners that install a solar system after 2027.

Even with additional credits, export compensation under the Solar Billing Plan is low. This makes the installation of a battery storage system to pair with your solar system important to maximize financial performance of the system. Using the battery system’s “self consumption” mode, excess energy generated from the solar system will first feed the battery until fully charged. Only then if there is surplus solar generation does the system export to the grid. As the solar system’s production begins to taper down in the evening, the battery will discharge to the electrical needs of the home.

When you have a solar system, your electrical use is calculated over a 12- month billing cycle called a “true-up period”. The electricity credits you earn by feeding the grid and the electricity debits you incur by pulling electricity off of the grid are tracked and applied month to month. At the end of the 12-month period you’ll get a True-Up statement, which in essence calculates the difference. If you used more power than you produced over the year, you’ll be billed for the overage. If you used less than you produced, your balance will be zero. Credits do not roll over year to year. PG&E also charges a monthly fee for you to be tied to the grid.

For many of us in PG&E territory, we also belong to a Community Choice Aggregation, or CCA. In San Francisco, it’s CleanPowerSF. In much of the East Bay, it’s East Bay Community Energy. In the North Bay, it’s Marin Clean Energy. CCAs manage the generation portion of electricity, while PG&E manages distribution and billing. 

Generally, CCAs provide better retail credit pricing for solar generation, however, if you have not built enough credits to offset usage, CCAs will bill you monthly for net usage overage, rather than through an annual True-Up bill.