Hatteras Island power outage and response

North Carolina's Hatteras Island experienced a power outage last week when construction activity damaged two underground transmission cables serving the island.  While the damage is repaired, residents face mandatory power conservation rules and visitors have been evacuated.

Hatteras Island is a barrier island located in North Carolina's Outer Banks.  While the island is relatively far offshore, it is connected to the northern Outer Banks islands by the Bonner Bridge.  Hatteras Island's roughly 4,000 residents and tens of thousands more seasonal visitors are supplied electricity by Cape Hatteras Electric Cooperative, a member-owned, not-for-profit electric distribution cooperative.

According to the cooperative, on July 27 a contractor building a replacement for the Bonner Bridge "accidentally drove a steel casing through the cooperative’s transmission cables" at the south side of the bridge.  The cooperative says it is taking steps toward both temporary and permanent solutions. For now, it is using a permanent diesel generator in the village of Buxton as well as temporary backup diesels to provide power to the island and is "working to expand the temporary generation service on Hatteras Island in order to accommodate a staged reentry of visitors." Meanwhile, the cooperative is working to splice the damaged underground cable and to build a new overhead transmission line, so permanent transmission service can be restored.

Calling the incident an "unprecedented complete loss of power delivery to Hatteras Island," Dare County issued a mandatory evacuation order for all visitors to Hatteras Island effective July 29, citing "life safety issues from the loss of reliable electrical power on Hatteras Island and growing uncertainty as to when repairs to the main transmission line will be completed to enable restoration of full power to the island."  Estimates suggested over 10,000 visitors have been kept off Hatteras Island as a result of the evacuation order, with proper credentials required for reentry.

According to the county's website, a complete repair might take from one to two weeks.  The county notes that the on-island diesel generators "will only be able to run if load is at minimal levels and everyone is conserving." The county cites mandatory power and water conservation measures in effect, including a requirement to disconnect system circuit breakers for air conditioning systems and hot tub heaters.