Subsea power connection to be commissioned this fall
Donna King’s island home and business are powered through a collection of subsea cables, but she’s found little reason to think much about it.
© — Photo by Joe Gibbons/The Telegram
Gary Murray (right), regional manager with Newfoundland Power, and engineer Jamie Mullins, who is in charge of establishing the new island-to-island connection, explain the power company’s plans for the upgrades to the Bell Island power grid system by three underwater power cables.
Whenever she flips the light switch at her store, Minnie Jane Convenience, the lights come on or go off as expected.
Aside from the planned outages and sudden blackouts experienced throughout Newfoundland last winter — specifically as Newfoundland and Labrador Hydro hit supply problems in January — she has not been worried about Newfoundland Power’s ability to reliably provide her with power.
“I’ve got to say, overall I’ve got no problems with them. So far, so good,” she said at her store, where cold drinks and ice cream were being sold from whirring coolers on a hot, sunny day.
King and several others on Bell Island told The Telegram their power service is, put simply, solid.
Newfoundland Power is promising more of the same, as it undertakes replacing the island’s subsea link with a new and improved set of cross-the-Tickle, underwater power lines.
Bell Island has sourced electricity from the Newfoundland “mainland” at Broad Cove, in Portugal Cove-St. Philip’s, since 1930. Currently four subsea cables are used to feed the island, running to the old Dominion Pier substation, not far from where iron ore was once off-loaded.
Three cables carry the power supply demanded by the roughly 1,550 Newfoundland Power customer accounts on the island. The fourth cable is kept at the ready in case a main line goes down.
Two of the cables were laid in 1988 and two in 1990. The link as a whole cost about $3.5 million to establish.
The new cable link — with two cables, each with three conductors inside — is estimated to cost $14.5 million.
It has already been approved by the Board of Commissioners of Public Utilities (PUB) and onshore work has started. Islanders can expect to see activity increase around the Dominion Pier and on the water in the Tickle, up to the laying of cables in mid-September.
“Each cable is about 230 tons, about 40 kilograms a metre, and the laying operation is pretty delicate coming across on the barge,” said Gary Murray, the regional manager with Newfoundland Power.
The barge will be equipped with the capability for dynamic positioning and roll-out of the cables to specific locations along the ocean floor.
“It’s not a small feat by any stretch,” added Jamie Mullins, an engineer who has taken a leading role in establishing the new island-to-island connection.
Both men stood together at the pier substation, taking questions on the work. Nearby, a giant sign loomed, reminding passing boats not to drop anchor in the area, protecting against accidental damage to the subsea cable.
A submarine survey has shown a 180-metre-long scar on the ocean floor off Bell Island, believed to be from iceberg scouring. Yet the scouring would be from “ancient times,” according to Murray, who is not worried about icebergs damaging the utility’s new subsea power lines.
“We don’t think it’s a factor here,” he said, speaking with the backing of decades of data.
The two Newfoundland Power employees said the utility will bring in a mobile generator to ensure people on the island do not experience significant interruptions in their power service as the new cable is installed.
“Customers, at the end of the day, will not see any outages, except for maybe a brief, five-minute outage for switching. Nothing substantial,” Murray said.
The new cables are being installed because the existing cables have come to the end of their expected operating life and are beginning to have failures, with costly repair work required each time.
In 2008, Bell Island experienced a roughly three-hour power outage as a result of a failure in a cable. The repair took about one week.
In 2012, there were two cable failures. First, in early January, power went out for about two hours. A second failure in April required 10 hours for restoration, with the help of a contingency plan. The total cost for the 2012 repairs was $903,000.
The new cable lines are designed to last 40 years.
The subsea power link was determined to be the least-cost option for supplying power to Bell Island. According to a submission to the PUB by Newfoundland Power, wind and solar options were also considered.
“Electricity generation using these technologies is limited by weather conditions and availability of wind or sunshine,” the submission states. “To provide reliable supply to an isolated customer load, these technologies must be supported by energy storage and/or dispatchable supply resources such as diesel generation. This requirement would materially impact the cost of such an isolated diesel system.”
As for the existing cables, they will stay where they are, according to Newfoundland Power, so as not to disrupt the ocean environment any more than necessary.