What Nova Scotia can learn from Sweden's decision to bury many power lines

Dorian may have blown through Nova Scotia, but the debate it stirred up about how to better stormproof the province's electrical grid has stuck around, with many people asking why the utility simply doesn't bury power lines underground to better prevent outages.

After all, some countries like Sweden have already taken that step and buried many of their low-voltage power lines in urban areas. Low-voltage lines are commonly attached to homes and small businesses.

After huge storms struck Sweden in 2004 and 2007, the country's power regulator forced electrical utilities to find ways to reduce how often power outages occur, said Eva Vittell, head of customer and market relations with Vattenfall, a power utility wholly owned by the Swedish government.

One of the solutions they decided on was to bury some lines.

What Sweden does

"That meant that we stormproof our network by using underground cables, but also by using insulated power lines in the locations where we still have the overhead power lines," Vittell told CBC's Maritime Noon. "All of those activities improved the situation."

Many rural Swedish communities and rocky areas still have overhead lines though, and high-voltage transmission lines are still needed to transport power over long distances.

The country also has older underground power lines that were installed in some urban centres in the 1950s and 1960s, mainly to conserve space.

However, Sweden has added 200 kilometres of additional underground power lines every year since 2007, said Vittell.

Portions of Nova Scotia's power grid are also underground, said Karen Hutt, president and CEO of Nova Scotia Power.

"We do that where it makes sense and particularly now going forward if there's a new subdivision or if there is a new building going up," said Hutt in an interview last week.

The cost of burying lines underground

That's just a tiny portion of the 32,000 kilometres of power lines criss-crossing the province. To bury it all would cost a lot of money.

"In some cases, it's 10 times more expensive to bury power lines versus running them above ground. I don't want anybody to think that we're opposed to that, that's not the case, but we cannot have that conversation without also talking about affordability," said Hutt.

In Sweden, it was generally three to five times more expensive to bury low-voltage lines rather than have them on poles, but were up to 10 times more if the lines had to go through rocky areas, said Vittell.

She said that since 2007, it's cost about $4 billion US to bury lines, the majority of which was spent on cabling.

That cost is passed along to customers. They've seen their power fees increase over the last number of years as stormproofing continues and the grid is expanded to handle the country's growing cities.

The downsides of underground lines

While the underground lines help prevent outages during bad weather, the system isn't perfect.

"When we do have an outage on an underground cable, the fault repair time is longer. And we can have a situation where we don't know exactly where the problem is," said Vittell.

That problem gets compounded as Swedish cities continue to grow and construction and repair crews accidentally pierce power lines when they dig.

Still, Vittell believes burying power lines is a great option for cities.

"We think it's the way to go for the local network, for the low voltage," she said.