Before we answer this very common question that we receive on a daily basis, we want to point out that most solar systems installed today are meant to remove a cost (your electric bill) rather than provide an independent power source from the electric grid.
There is a common misconception that your solar system will keep producing electricity even when the electric grid ‘goes down.’ Unfortunately, this is not true for most solar systems at this time, unless you have a battery back-up system or have a special solar inverter that is designed to provide limited power for limited amounts of time. This is due to both the technical and safety reasons mentioned below.
Solar panels produce varying amounts of electricity per day (depending on the sun’s location or amount of clouds, etc.) and a typical household/business uses varying amounts of electricity per day.
If the grid would ‘go down,’ a solar system may produce 30 kWh (kilowatt-hours) in a day, however your house/business is trying to consume 35 kWh. This would lead to appliances and lighting not working properly or not at all.
The one solution, would be to install a battery back-up system to keep consistent loads throughout the day and through the night. However, battery systems are currently cost-prohibitive for most people.
To understand why solar systems can work without a battery back-up system by being grid-tied, read our blog on net-metering.
Secondly, national electrical code requires that your solar system shut down when the grid ‘goes down.’ If the grid goes down in a neighborhood and the local utility is fixing the power lines locally, it would be unsafe for a solar system to be pushing excess electricity production from a solar system back to the grid.