The New York Times

When Hurricane Sandy wiped out the power in areas like coastal Long Island and the Jersey Shore, what should have been beacons of hope — hundreds of solar panels glinting from residential rooftops — became symbols of frustration.

Despite the popular perception that installing solar panels takes a home “off the grid,” most of those systems are actually part of it, sending excess power to the utility grid during the day and pulling electricity back to run the house at night. So when the storm took down power lines and substations across the Northeast, safety systems cut the power in solar homes just like everywhere else.