The way power plants know what real-time power adjustments are needed is by closely monitoring the grid frequency. The goal is to provide electricity at a constant frequency—60 hertz—at all times.

But the grid has changed. There are more renewable energy sources, from which power isn’t always available – like solar panels at night or wind turbines on calm days.

By the night of June 24, more than 71,000 customers were without electricity in Michigan, Pennsylvania, New York, and Massachusetts, according to Poweroutage.us.

National Grid's Eastern New York Regional Control Center in Guilderland, pictured here on June 26. Bethlehem residents experienced consecutive nights of power outages after extreme weather and ...

ROCHESTER, N.Y. — Power has been restored for most customers on Monday morning after a wave of power outages on Sunday night in Monroe and Wayne counties. At one point, 1,700 customers were ...

About a year ago, O'Gorman used his truck for a three-day power outage at his 1845-built, 3,700-square-foot home, where he loses power a few times a year. It was cool enough where the house didn't ...

National Grid reported at 10 p.m. that about 1,243 customers were without power in Bristol County. Eversource is reporting about 3,905 power outages in Eastern Massachusetts.