December 20, 2015

All villages are now back on the transmission power


Today is considerably quieter in the area of Light Plant Road in Buxton, where the diesel generators that have produced the power Hatteras and Ocracoke have been humming away for the past five days.  The generators were completely shut down at 9 a.m. on Sunday morning when the islands went back to getting their power from the transmission lines.

Crews working just south of the Bonner Bridge finished splicing the three cables that carry power across the bridge and down the island back together yesterday, and then the Cape Hatteras Electric Cooperative re-energized the transmission lines.

However, Hatteras and Ocracoke remained on generator power overnight, while CHEC tested the transmission lines.

This morning, the cooperative began adding villages to the power load in stages.

First came Rodanthe, Waves, and Salvo, at 7 a.m., which required a 30-minute outage.  The northern villages were quickly followed by a very brief outage of fewer than five minutes to add Avon and Buxton.

CHEC had planned to monitor those five villages for several hours before adding the rest of Hatteras and Ocracoke, but Susan Flythe, executive vice-president and general manager, said everything went so well that Frisco, Hatteras village, and Ocracoke were added at 9 a.m. without even a blip in the power.

Flythe also noted as an aside that the N.C. Electric Membership Corporation owns the generators, and the half dozen or so workers who had been here since the switch to generators last Wednesday, Dec. 16, were eager to get home for family Christmas events.

Cutting the transmission cables, relocating them, and then splicing them back together is a project that had to be completed before contractors for the North Carolina Department of Transportation could begin construction of the replacement for the Bonner Bridge over Oregon Inlet, which is scheduled for March.

The islands were switched to generator power on Wednesday, Dec. 16, and CHEC had announced that the project would take seven days -- until Tuesday, Dec. 22.  However, Flythe said the work crews for the contractor, New River Construction, became faster with each of the three cables they were required to splice back together. They were  also able to work through Friday's wind and rain.

The weather was mild for the first three days on generator power, but CHEC managers were concerned about the cold snap that began Friday night and lasted into this morning.
Temperatures fell to about 40 early Saturday morning, but did not fall as low as forecast on Saturday night.

The generators on the two islands and three that were brought in for the job were capable of providing 24 megawatts of power.  However, CHEC said a "cushion" was needed and aimed to keep the load at about 20 megawatts.

CHEC managers looked at historical data for a weather forecast similar to the one for this weekend and were concerned about the load. They decided to ask members to conserve electricity beginning Friday night.  The cooperative also asked property management companies to turn off the power at unoccupied rental cottages, so that heat pumps in those houses would not switch on when temperatures dropped.

Apparently, it all worked as planned. The power load during the day ran about 10 or 11 MW on the mild days of Wednesday through Friday and on Saturday, which had a high of only 48 -- and that actually occurred just before midnight last night.

The highest load was early Saturday morning with 15 megawatts, and Flythe said the peak load last night and early this morning was only 14 MW.

She attributes this to conservation by members, turning off the power at rental cottages, and the fact that the cold snap was brief and had been preceded by a week or more of very warm weather.

This morning on Facebook, CHEC was receiving accolades from members for how seamlessly the five days on generator power had proceeded.

CHEC, in turn, was thanking members who conserved and the crew from NCEMC who worked around the clock to keep the generators running smoothly.

"Let the Bonner Bridge construction begin," CHEC noted on its Facebook Page.


The Editor's Blog:  It will take a community to support seven days on generators.

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