Frequently Asked Questions

1What is Solar Electricity?

Photovoltaic (PV): photo = light, voltaic = produces voltage

Photovoltaic (PV) systems, also referred to as solar electric systems, convert sunlight directly into usable electricity in your home or business using semiconductor technology. Sunlight strikes the PV cells and cause the electrons to flow, creating an electrical current (photovoltaic effect).

2 How Does PV Work?

When the sun shines, sunlight is channeled from the solar panels through an inverter, which converts the energy into electricity that your house can use for your appliances, lights and any other equipment for your home or business. If you are producing more than your home or business is using during the day, the excess power will be sold to the utility company at the same rate you buy it for. You will be saving credits for use at night or for less sunny days. When the sun goes down, your panels no longer generate electricity. You will then tap into (your savings) electricity from your local utility company.

Photovoltaic (PV) systems convert light directly into electricity using semiconductor technology. Please see this illustration from SDG&E website. It explains how solar works better than words.

a) Individual photovoltaic (PV) cells are connected to panels. Solar panels convert sunlight into direct current (DC) electricity.

b) An inverter converts direct current (DC) into alternating current (AC) for electricity in the home.

c) The utility meter records the net amount of energy generated through the PV system. When you’re creating more electricity than you’re using, your meter will spin backward and the excess electricity is sent to the electric grid. This helps to offset the cost of your electricity usage at night or on cloudy days when your system is not producing electricity.

Important Notables!

1. Solar panels often produces more power than you use, feeding back the extra power into the utility grid.

2. You will always use solar electricity first before using any electricity from the utility company and pay for ONLY the extra power you got from the utility company.

3. If the size of your system produces enough or more electricity than your power usage, the utility company will reimburse you for the excess power your system produced.

3How much do photovoltaic systems cost?

The price of a photovoltaic system is determined based on a number of factors, including system components and configuration, the difficulty of installation and available incentives. To be clear, the costs mentioned here are the installed cost. This means the final cost (before rebates) to the consumer for the equipment and labor to install and connect a photovoltaic system. The cost of solar has decreased by 48% since 1998.

The current average installed cost ($)/watt for a residential solar electric system in California is between $4-$7/watt, while larger commercial and institutional systems typically cost $3-$7/watt. Generally speaking, the larger the system, the lower the cost. In addition, the larger the number of systems, for example a new home construction development of 200 homes, the lower the cost.

4What size system should I install on my home or business?

Every site is different and the needs of the homeowner vary. System size depends on several factors; including how much electricity (kWh) is consumed on site, the orientation and tilt of the system, as well as available roof space and capital.

The first step is to determine the annual kWh consumption of the home or business. Once calculated, you can pinpoint avenues on how to reduce your energy consumption by implementing energy-efficient improvements, a necessary first step before installing solar. If you reduce your kilowatt-hour consumption, you may be able to install a smaller PV system, in turn allowing for lower up-front costs and a shorter payback period.

5Do solar panels and inverters come with a warranty?

Your solar panels will come with a 25-year production warranty. Your micro-inverter comes with a 25-year warranty, while your string inverter will come with a 10-year warranty. Most string inverter manufacturers offer a supplementary 10-year extended warranty for an additional cost.

6What is net metering?

This program is for customers with solar electric or wind generating systems. If your system produces more energy than you use, you can earn bill credits for the excess power you put back into the SDG&E electric grid. You can later use that credit to cover the power you may need from SDG&E at times when your own self-generation doesn't fully meet your needs.

7Does San Diego Gas & Electric offer net metering?

Yes. Under California law, all public and private utilities, including irrigation districts and cooperatives, that operated prior to January 1, 1998, must offer net metering. New electric service providers, who began selling electricity after January 1, 1998, may choose to offer net metering.

8What are the benefits of Net Metering?

You can receive full retail value for the production of your system.

Net metering allows you to use the power that your solar electric system produced and offset the consumption in your own home. SDG&E acts as a bank to store your production, then allowing you access that power to offset your own consumption. This is equivalent to getting full retail value for the power your system produced.

You can receive wholesale value for the excess production of your system

If you solar electric system produces more than kWh you consumed annually, SDG&E will purchase excess energy from you, at a wholesale rate. Currently, the buyback rate is ~$0.04/kWh. (See the Net Metering Section for more details.)

You can store power on the utility grid.

Due to the fact that you get credit for your excess power generation, it is not necessary to install a battery storage system. However, some may still decide to opt in for a battery backup for storage. Through net metering, SDG&E acts as your “battery bank,” storing your power free of charge.

The interconnection process is streamlined.

Customers participating in net metering can use the simplified interconnection online application. This is particularly beneficial to businesses because it simplifies a previously complex process.

9How do I sign up for net metering?

It's simple. As soon as you decide to install a PV system, visit the net metering application page to get started. Often, the installer will apply for the business or homeowner. Once all installations and inspections are completed, the homeowner and installer will receive the Permission To Operate (PTO) letter.

Only at this point are you permitted to turn on your system.

SDG&E Net Metering:

PHONE: 858-636-5585

EMAIL: ornetmetering@semprautilities.com


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