Microgrid Helps North Carolina Island Recover from Hurricane Dorian’s Devastating Blow

Thanks to its microgrid, North Carolina’s Ocracoke Island was able to restore power three days after Hurricane Dorian sent a tidal wave smashing into its coast line, causing massive flooding.

Initially, both the grid and the microgrid went out of operation when the hurricane struck September 6, and flood waters rose 13 feet. Local service provider, Tideland Electric Membership Corp. (TEMC) said it had no choice but to shut down the microgrid given the wind and water.

“Dorian was a particularly catastrophic storm for Ocracoke that resulted in historic flooding on the island,” said Lisa Crawley, spokesperson for North Carolina’s Electric Cooperatives. “Because of flooding and structural damage, electric meters were pulled from nearly 400 homes — 28%  of the island’s meters — making it impossible to deliver electric service to them.”

She added: “The good news is that, when flood waters subsided, after safety inspections to confirm equipment was not damaged, the microgrid’s diesel generator did play a role in restoring power to the island sooner than if restoration were solely dependent upon transmission service.”

TEMC restored microgrid service to the Outer Banks’ island September 9 along with fallen power lines. The next day grid power was also restored.

 An island microgrid laboratory

Ocracoke’s population swells from a permanent resident population of some 950 to some 7,000 or more with the onset of summer and the influx of tourists who come to enjoy its North Atlantic Ocean beaches. Electricity is particularly expensive on the remote island — demand charges can run as high as 57 cents of every dollar spent on electricity. Furthermore, overhead power lines are exposed to the elements, leaving them vulnerable to high winds, storms and salt water.

A member of NCEC, TEMC and the electric co-op association carried out an initial initiative to improve grid service on Ocracoke back in 1990. It was then the project partners installed a 3-MW diesel generator to serve as a peaking power plant. Power became more affordable a TEMC spokesperson told Microgrid Knowledge.

NCEC and TEMC followed that up in January 2017 with the announcement they had formed a joint venture to install a hybrid microgrid on Ocracoke that combined a 15-kW rooftop solar PV array on top of the diesel power plant. A PowerSecure battery system stores power produced by the solar energy array, diesel generators and grid, while a Tesla controller manages microgrid power dispatch as grid conditions change.