Alberta electricity grid set for a power boost

Two new high-voltage, direct-current transmission lines to come on line

Alberta’s electricity grid has a stronger backbone with the completion of two high-voltage direct current transmission lines between Edmonton and Calgary, built at a combined cost of $3.5 billion.

AltaLink’s 350-kilometre, 500-kilovolt Western Alberta Transmission Line between Wabamun and Calgary became operational on Thursday.

Atco Electric is nearing the end of commissioning for its 485-km, 500-kV Eastern Alberta Transmission Line between the Gibbons area and Brooks, 190 km southeast of Calgary.

They are Alberta’s first DC transmission lines and the largest projects in each company’s history. AltaLink’s line cost $1.7 billion and the Atco project cost $1.8 billion.

Together they form “a very, very strong backbone” for Alberta’s electricity grid, Greg Retzer, vicepresident of transmission project delivery with the Alberta Electric System Operator, said Friday.

“This is infrastructure that’s been needed for a long period of time,” Retzer said. “Having the extra capacity allows for a stronger grid and higher levels of reliability. When events happen on the system — if we get thunderstorms or there’s generating plants that go down — it just allows us a lot more capability in keeping the lights on.”

The new lines will take pressure off an existing 240-kV transmission network between Edmonton and Calgary that is now being reconfigured to better meet the needs of central Alberta communities.

Direct-current transmission lines are far less susceptible to heat loss than alternating-current lines, making them more energy efficient. AltaLink says its new line will save an estimated 350,000 tonnes of carbon emissions per year from entering the atmosphere.

Each of the new lines can be modified to carry more electricity without the need to add extra transmission towers or conductor wires. Instead, converter stations at each end would be expanded.

DC lines are also highly controllable, allowing electricity to be pushed to where it’s needed.

AltaLink president Scott Thon said the ability to control the electricity flow will be of benefit to all Albertans, especially with the coming shift toward renewable energy sources. Testing last month provided a demonstration of how the typical north-to-south electricity flow in Alberta can be reversed, he said.

“When the wind was blowing in southern Alberta, we were flowing large quantities on the new HVDC line up into the Edmonton region from southern Alberta, and that’s just really unique,” Thon said. “That just speaks to the flexibility of the new technology.”

Atco Electric president Sett Policicchio said the Eastern Alberta line will be able to move wind and solar energy generated in southeastern Alberta to the northern part of the province.

“You have the opportunity to move greener energy to where you need it, and I think that’s a huge benefit to the province in the long haul,” Policicchio said. “These lines are built for the next 50 years.”

Both projects were approved by the Alberta Utilities Commission in 2012. Operating costs are recovered through transmission tariffs approved by the AUC.

“The forecast costs of both these projects have already been reflected in customer bills for two years now and so the actual energization of either WATL or EATL doesn’t cause any spike,” AUC spokesman Jim Law said. “Costs are generally smoothed over time."