BC Hydro investigating damage to submarine cables that carry power to Vancouver Island

BCHydro says extreme June heat may be to blame for damage to three submarine cables that provide power to Vancouver Island from the mainland.

The provincial Crown corporationsaid in a newsrelease Monday thatits monitoring system first detected a bulge and oil leak on July 8 in acablethatruns underwater from the Sunshine Coast to the island. After that initial discovery, two other cables were discovered over the weekend that arealso bulging.

BCHydro said the leaking cable was taken out of service, and theleak, which consisted of non-toxic mineral oil, has been contained. The load on the other two cables has been reduced, and theyare being closely monitored.

The cables that were affectedrunfrom the Sunshine Coast, over Texada Island, then travel underwaterto Nile Creek, near Qualicum Bayon Vancouver Island, where they connect above ground with the Dunsmuir Substation that then sends power up and down the island.

The cables, which are manufactured in Norway, each measure15.24 centimetres in diameter. Inside is mineral oil that acts as a coolant surrounded bycopper pipe that conducts electricity. The copper pipe is covered in lead, which is covered in plastic and the entire cable is then sheathed in concrete.

Ted Olynyk, BCHydro'scommunity relations manager for Vancouver Island and the Sunshine Coast, told CBCNews Tuesday morning that the cable leak happened above water close to a terminal point on Texada Island, so repairs on that cable can be done above ground.

He said fixing the cables is complicated work, but islanders should not worry about losing power.

"We have enough to meet our load," said Olynyk, which he said is roughly1,000 megawatts at this time of year.

He said the island is still receiving sufficient power from another set of cables that runs fromTsawwassento Duncan, can produce its own on-island powerand can rely onindependent power producers on the island to help fill any gaps.

However, as a precaution, BC Hydro hastold its largest industrial customers on the island they may need to reduce their power use.

"We are just advising that it may come to that," said Olynyk.

While an investigation is underway to determine what caused the damage, Olynyk said the cables were inspected in May and again in mid-June justbefore the recent heat wave blanketed B.C.

When last inspected, Olynyk saidthere were no "abnormalities" seen on the cables.

Temperatures in late Juneshattered previous heat records this year with the mercury hitting 40 C in Vancouver and substantiallyhigher in the Interior.

"I think it's pointing to that direction [the heat wave] at this point," said Olynyk, adding he does have concerns for the future of the infrastructureif such heat events become more common.

According to Olynyk, about 70 per cent of the island's electricity is supplied by cables coming from the mainland.

B.C.'s high-voltage transmission system consists of more than 18,000 kilometresof power lines and underwater cables. Seventy to80 per centof the province's electricity is consumed in the Lower Mainland and on Vancouver Island.

Electricity is supplied to the Lower Mainland and Vancouver Island from the Peace River hydroelectric system through Kelly Lake Substation, and from the Columbia River system through Nicola Substation.