Net Energy Metering/ Battery Storage

When you go solar in San Diego, you are becoming an energy providing partner with SDGE. When the system is producing more electricity than the house is using, the excess power is sent back to the grid and SDGE credits you at full retail. This is an incentive put in place by the state of California because it allows people to use SDGE as the “battery.” Instead of storing that power in personal battery storage for later, SDGE buys the power you send back at full retail price and gives you a credit. This allows most people to forgo having to purchase an expensive battery system.

This is a major component to why the economics of solar in San Diego yield payback periods half of what it is in most parts of the country. In most other states, the utility company only buys back electricity at a very low wholesale rate. In this scenario, it is often times more valuable to store it in a home battery for later. This increases the overall cost of the project and slows the payback period. In most parts of the country payback periods are around 10 years.

It is not true that batteries help you save money. I commonly hear that homeowners believe the battery stores power to use during peak hours and this will ultimately save them money because they will be avoiding the peak rates. But, the battery costs much. more than what it would save you.  

Here is a visual of how we SDGE bills us for power along with credits solar owners for their back fed power.

A battery does make sense for some people in San Diego; those who are dealing with constant blackouts or power outages. This is when the battery would kick in and allow you to have the lights on. If you do not have a battery and the grid goes down, your system has an automatic “rapid shutoff” feature because it cannot be sending power into the electrical lines when an SDGE lineman is working on repairing them. If you want peace of mind that your refrigerator will always be powered even if the grid is down, then a battery could be worth it if the cost seems justifiable to you. Don’t confuse it as a money saving tool against peak hours though.

A Tesla Powerwall 2 is $12,000-$15,000 after installation. The benefit to the battery is you can take the 26% tax credit on it and there is a California rebate that could be worth a few thousand dollars. 95% of houses we install solar on forgo the battery with the current net metering 2.0.