If San Diego Gas & Electric shut down parts of the grid during Hurricane Hillary, most solar homes would still be without power.
On Friday night, SDG&E spokesman Anthony Wagner confirmed that the facility did not plan to cut power, which is known as a public safety outage. But if conditions call for power outages, most solar power systems can't provide power to homes and businesses on their own.
And this is for safety.
"In the event of an unexpected outage, standard grid-connected solar systems are scheduled to shut down to prevent unexpected power from being sent to the power line during repairs," Wagner wrote in an email. .
So rooftop solar is pretty much useless when it's off-grid, that is, when it's not connected to a battery.
This is how rooftop solar works: When the photovoltaic cells on the solar panels convert sunlight into electricity, the energy is instantly converted into electricity. Although San Diegans have more rooftop solar panels than any other part of the state, most of those panels are still connected to the state's larger electric grid, where nearly all are subscribers.
Some solar systems can "isolate" or continue to power some or all equipment during an outage, but solar customers should check with their contractors for more information about this capability.
A grid-tied solar system is the cheapest form of rooftop solar energy. It can also be profitable. Owners of grid-tied solar panels still benefit from selling excess solar energy that doesn't require a home or car grid. This is called net energy measurement. According to the California Public Utilities Commission, approximately 90% of solar panel owners participate in this program.
Solar consumers can be completely disconnected from the grid, but this usually requires the addition of batteries large enough to power the home at night or on cloudy days. These batteries cost thousands of dollars. Most of them are made of lithium and other rare metals that are expensive to mine.
The core of Hurricane Hillary is expected to move toward southern California late Sunday, possibly weakening to a tropical storm. But the National Hurricane Center still expects strong winds and heavy rain until then.
SDG&E has increased field personnel and scene equipment to quickly respond to potential or extended power outages, according to a news release.
Wagner added that if anyone sees a downed power line, immediately call 911. Do not touch it as it could still be live and cause a dangerous electric shock. If residents smell gas, they should leave the building immediately and call 911.
