Mega-dams to lose megawatts: Line loss increases with distance travelled

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This article was published 18/01/2011 (5602 days ago), so information in it may no longer be current.

More than 10 per cent of the power generated by the next generation of mega-dams will vanish when it’s shipped south down the three Bipole transmission lines, including the contentious west-side line.

According to estimates Manitoba Hydro released following an access to information request, 479 megawatts of power will disappear from Bipoles I, II and III once the Keeyask and Conawapa dams are built.

The phenomenon is called “line loss.” The more electricity that flows down a high-voltage line and the longer the distance, the more power evaporates. Once Keeyask and Conawapa are up and running in 2023, total line losses will grow by 254 megawatts to 479 megawatts.

That’s a sizable amount of new line loss. It’s about 11 per cent of the 2,100 megawatts Hydro is planning to build with Keeyask and Conawapa and effectively cancels out the new power coming on stream next year with the Wuskwatim dam.

And the figures are likely to fuel critics like the provincial Tories, the Canadian Taxpayers Federation, the Association of Manitoba Municipalities and even a group of engineers. They say the Selinger government is wasting hundreds of millions of dollars by forcing Hydro to build the new Bipole III transmission line down the west side of the province instead of using the shorter, cheaper route down the east side of Lake Winnipeg.

Tory Leader Hugh McFadyen said the west-side line is not only dramatically more expensive to build, but wastes more valuable power that could be sold for export.

“That is just compounded as we add new generation in the north,” he said.

But Hydro officials say line loss is an unavoidable part of operating remote generating stations. And they pointed to recent comments by Hydro president Bob Brennan, who told MLAs building Bipole III down the east side of Lake Winnipeg instead of the west side of the province would only save about 40 megawatts. That means total line losses would still be about 439 megawatts instead of 479.

With the support of several environmental groups and some east-side First Nations, the province says a power line would degrade one of the last pristine boreal forests and diminish the province’s chance of winning a UNESCO World Heritage Site designation.

maryagnes.welch@freepress.mb.ca

-- What's line loss?

It's the amount of power that's lost during transmission, especially over great distances. Even an efficiently built power system suffers from line loss.

-- How much line loss is there now?

A lot, because the two major transmission lines, Bipoles I and II that run through the Interlake, are maxedout on power. About 301 megawatts bleeds off the two lines now.

-- How much line loss will there be once Bipole III is done?

Less, at first. Losses will shrink to 225 megawatts, allowing Hydro to sell 76 megawatts of power that was previously lost into the ether.

-- What happens when we build more mega-dams up north?

We're right back where we started, and worse. Once Keeyask and Conawapa are up and running, likely by 2023, the three transmission lines will once again be almost at capacity. By then, we'll be losing a total of 479 megawatts in line loss, an extra 254 megawatts.

-- How much better would it be if we built the power line through the boreal forest on the east side of Lake Winnipeg?

About 40 megawatts better. That's worth about $230 million over the life of the project -- not huge dollars in the great scheme of things. Total line losses would be about 439 megawatts.