Alberta Premier Rachel Notley says rising transmission costs in the province can be linked to the previous government's construction of new infrastructure.

Responding Thursday to a report submitted to the Alberta Utility Commission by a coalition of consumer groups, Notley acknowledged that the issue of rising transmission costs was "predictable."

"The government knew, well before we got elected, that they had embarked upon a process of approving infrastructure build that was going to significantly increase cost to consumers," Notley said.

"We knew that the transmission cost issue, which people that have raised today, was one that was coming down the pipe."

In the report, the coalition said it's "concerned by the substantial increases in transmission rates that have already occurred and further increases that are forecast to occur in Alberta."

The coalition includes the Industrial Power Consumers Association of Alberta, the Consumers' Coalition of Alberta and the Alberta Direct Connect Consumers Association.

"The biggest [cost] driver has been new build," said Vittoria Bellissimo, executive director of the Industrial Power Consumers Association of Alberta.

"We end up with rates that are really going up more than they have in decades before hand."

The report — which was filed in January and is part of an ongoing regulatory proceeding — says the cost drivers are a "threat to the long-term sustainability of Alberta's integrated electric system."

But the Alberta Electric System Operator said the costs forecast in the report are "overblown." On Twitter, AESO stated it expects transmission costs will continue to make up about 20 per cent of the average residential bill. That cost is expected to rise from today's average of $21 per month to $27 per month in 2021.

Over the next 20 years, we project transmission costs to continue to make up about 20% of the average residential bill. (2/3) —@theAESO

"While it is crucial we have a reliable electricity grid that keeps pace with a growing province, the previous government was not clear with Albertans about what the costs would be and who would pay for their decisions," said Energy Minister, Marg McCuaig-Boyd in a statement to CBC.

"Consumers are now seeing some of these costs on their bills and rightfully asking questions. Albertans need to know their electricity system is working for them to provide affordable, reliable and cleaner energy to their homes."