Solar Technology FAQs

Solar energy benefits you and the environment, and it's a good way to contribute to energy sustainability. You can reduce your monthly electric bill and also play an important role in moving the state toward a cleaner energy future.

Solar electric or PV technology uses the sun’s energy to make electricity. When sunlight strikes an array of solar panels, electrons are freed by the interaction of sunlight with semiconductor materials (typically silicon). The movement of electrons creates current, thus creating direct current (DC) power.

DC is the only type of current produced by solar cells. Appliances and machinery, however, operate on alternating current (AC) as supplied by your utility. The DC energy produced by the panels is fed into an inverter that transforms the DC power into AC power, which then feeds into the main electrical panel that powers your house or business.

You will want to consider how much sunlight your property receives. Your property should have clear access to the sun for most of the day, and throughout the year. Since shading will reduce the amount of electricity your system will produce, PV panels should be installed in a location that is not shaded by trees, chimneys, or nearby structures.

The best orientation for a PV system is on a south or southwest-facing roof. Flat roofs can work, since PV arrays can be mounted on frames tilting south or southwest. PV arrays can also be mounted on the ground.

Several factors will influence the size of the solar electric generating system. The first step in determining the appropriate size is to conduct a free energy efficiency audit and implement measures to reduce the amount of electricity you need. The second step is to review your previous 12 months of electricity usage. Typically, solar installers and contractors will be able to help you with these steps.

Residential solar energy systems can vary in size from 50 square feet to 1,000 square feet. As a rule of thumb, a square foot of PV module area produces 10 watts (W) of power in bright sunlight. The total system size will depend on the amount of energy you would like to produce to offset your current usage. For example, a 2,000 W system can produce 3,500 kWh on average during the course of the year (depending on the specific roof orientation and efficiency of the solar panels), and would require 200 square feet of roof area.

When you install solar, an electric panel upgrade is sometimes required by your local building and safety department. This is to ensure your electrical panel is up-to-code and can support an added electrical load. 

This is common in older homes and may be necessary depending on the specifics of your system, structure of your home, and changing electricity needs.  

Please note that upgrading your electric panel is not the same thing as reprogramming your electric meter. When you go solar, meter reprogramming will be a part of the process and will be handled by SCE and your contractor before you can operate your system.  

In California, a PV system will produce the most electricity in spring through fall, when sunlight hours are the longest and the sun is positioned higher in the sky. A 1,000-watt (or 1 kW) system can produce from 1,400 kWh to 2,000 kWh per year, depending on the efficiency and location of the solar panels. Generally, a PV system in Southern California will produce more electricity than one in Northern California. 

A kilowatt, or kW is a unit used to measure electric power. 1,000 watts is equal to 1 kW.

A kilowatt-hour, or kWh is a basic unit used to measure energy consumption. For example, ten 100-watt light bulbs left on for an hour will consume 1,000 watts per hour, or 1 kWh of electricity.

The cost varies depending on many factors, including the solar energy system’s size, equipment options and labor costs. Typically, the installed costs are determined based on the size of the system’s output. The “cost per watt” ($/W) is often used for comparing systems of different sizes.

For information on what is included in the total cost of a home energy system, and how to compare bids and financing options, please visit the California Solar Consumer Protection Guide.

You can visit the SCE Solar Marketplace, an easy-to-use, one-stop shopping service; offering customers a reliable resource to search solar vendors, compare prices of rooftop solar systems, finance options, and receive the benefit of having multiple vendors bid for their business.

The best way to maximize your solar generating system is to understand two things: how your system functions and how your rate plan works.

How your solar system functions: Solar generating systems capture sunlight and convert it into electricity that powers your home. For your system to work the best it can, it needs to be installed correctly, and maintained professionally. Here are a few things to keep in mind for installation and care:

• Placement: Your system functions best when it has direct access to sunlight throughout the day. Your contractor should determine optimal placement for your panels to capture direct sunlight during daytime hours.
• Sizing: Make sure you’re installing a large enough system to produce the energy you need. Your contractor can help decide what size system you need installed.
• Cleaning: Having your panels periodically cleaned and serviced by a licensed professional will help keep them operating at full capacity.

How your rate plan works: NEM 2.0 customers are placed on a Time-of-Use (TOU) rate plan. A TOU plan prices energy more affordably during off-peak hours, which include the daytime hours of 8 a.m. – 4 p.m., when your panels will be capturing sunlight. Shifting energy use to these hours, instead of times when your system isn’t producing energy (such as at night or when it’s cloudy), will help you use more solar energy, and less grid energy overall, at the most affordable price during the day. Here are a few tips for shifting energy to make the most of your system: 

• Shift major appliance and equipment use to off-peak daytime hours (8 a.m. - 4 p.m.) when your solar generating system is active.
• Try not to use too many appliances simultaneously during the day, so your system can keep up.
• Run your pool pump during the daytime.
• Consider investing in a battery storage system to keep more of your self-generated energy for use at night when electricity costs can be higher.

You can always view your usage history by logging into My Account online. You’ll be able to see when your system is generating more than you’re using (excess electricity that is exported to the grid) and when you’re consuming energy from the grid. This can help you find opportunities to shift your usage going forward.

The California Solar Rights Act, enacted in 1978, limits the ability of covenants, conditions and restrictions (typically enforced by homeowners associations) and local governments to restrict solar installations. Get more information on the California Solar Rights Act.

For tips on maintaining a high-performing solar energy system, visit our Solar Maintenance Fact Sheet.

No, a solar generation system operates automatically, and shuts itself on and off automatically.

If a power outage occurs, your solar energy system is designed to immediately shutdown for safety reasons. A grid-tied solar electric system does not provide power during outages unless it includes a battery storage system. Your power will be reinstated moments after grid power is restored; however, you may need to manually reset your solar system’s inverter back to service after your power is reinstated (most auto reset after power is restored). 

Learn more about going solar by visiting the California Solar Consumer Protection Guide.