EFFICIENT ENERGY: Battery-storage technology is key to providing economic power sources for consumers.

• Author: Saylor, Teri

A microgrid installed on Ocracoke Island couldn't stop Hurricane Dorian's heavy wind and flooding from knocking out power in September, but it was instrumental in getting the island up and running after the floodwaters subsided.

Ocracoke Island's remote location is isolated from central power-generation sources and leaves the island vulnerable during weather events. A microgrid is a small electric system that combines local energy resources and control technologies to provide power when needed. It's connected to the main grid, but can operate independently.

The island's service provider, Tideland Electric Membership Corp., restored power through the local microgrid on Sept. 10, just four days after the storm.

"These microgrids allow users to disconnect from the main grid and provide a steady flow of electricity to address demand," says Lee Ragsdale, senior vice president of energy delivery at North Carolina's Electric Cooperatives, a Raleigh-based group of 26 not-for-profits that provide power for 2.5 million residents in 93 counties. "They put excess power into storage for use when needed, such as during storms or other natural occurrences that interrupt electricity, or if demand exceeds availability."

The Ocracoke site is one of two pilot projects by the state co-ops. The other is in Lillington and is a collaboration with a local electric co-op, South River Electric Membership Cooperative, and Butler Farms, a hog operation. The Butler Farms microgrid incorporates alternative-energy sources, including biofuel from swine waste, solar energy and battery storage. In addition to using the electricity it generates, the farm also sells power it produces to South River.

Fifteen years ago, technology wasn't available to enable this type of large-scale energy storage, says Jim Hoelscher, president of LS Energy Solutions of Charlotte. Renewable energy sources such as solar and wind power required the technology to advance quickly. Because solar...