Alberta Electricity System Operator approves substation upgrades to handle wave of renewables

Posted on April 27, 2023 by Ryan Dahlman

By Collin Gallant

Southern Alberta Newspapers

Substation upgrades to increase the flow of renewable power out of the southeast region could proceed next year.

The Alberta Electric System Operator had been evaluating a plan by line owner AltaLink to boost capacity of the Bowmanton Substation, located about 40 kilometres northeast of Medicine Hat.

It gave initial approval earlier this month to add three banks of shunt capacitors and circuit breakers to limit congestion at an estimated construction cost of $11.2 million, according to engineering reports.

An alternate option of adding another substation may have cost up to $55 million. Power lines in and out of the southeast consist mainly of a 240-kilovolt doubled-line that runs from Cassils (near Brooks) to Bowmanton then south to Whitla (near Bow Island), sometimes described as the CWB system.

There are currently renewable facilities using the line with a cumulative capacity of 793 megawatts in peak conditions.

New power plants totalling 963 megawatts of proposed capacity have met “inclusion requirements,” meaning they have paid fees to book space on the system for when construction is completed over the next two years.

In total, the AESO has dealt with inquiries from proposals totalling 6,000 megawatts in the planning region.

Longer-term solutions include initial analysis of closing the hook-like configuration into a loop by joining the Whitla station to lines in and around either Brooks or Lethbridge, but with cost estimates above $400 million for new line construction. Upgrading lines between Bowmanton and Empress is also being considered to provide a higher capacity outlet.

Those options were discussed in longer-term planning documents, published in February.

“Given the fast pace of generation developments in the Medicine Hat planning area, congestion on the CBW path is anticipated to occur in the near term,” the report reads, noting the current upgrades will “reduce the anticipated congestion in the near term before the significant infrastructure identified in the 2022 Long-term Transmission Plan is in place.”