Why Grid-Tie Inverters Sometimes Don't Allow PV Panels to Produce Electricity in a Utility Power Outage

Interesting article at www.renewableenergyworld.com about grid-tie inverters and how they don’t always allow residential solar owners to generate electricity from their PV panels when a local utility has an outage. Says the article:

“This is a very common assumption made by grid-tie PV homeowners: PV systems will continue providing power during a power outage as long as the sun is shining. However, commonly used grid-tie inverters safely disconnect from the utility grid if the grid goes down and won’t deliver power even though the sun is up and shining.  This is, in part, a safety precaution required to protect utility workers repairing the wires and prevent fires.”

The Renewable Energy World article says that in Japan, “Standard grid-tie inverters disconnect themselves from the grid, but can draw a small amount of power from the PV system even during daytime power outages. Production of emergency energy is enabled by a function of the inverter known as “independent-operation.”