Alberta's New Democrats say the provincial government is being wilfully blind to evidence that new power line construction will send electricity bills through the roof.

NDP Leader Brian Mason released a letter Monday that was sent to the government caucus last fall by two electricity consumer groups.

Alberta Direct Connect and the Industrial Power Consumers Association of Alberta warned that a projected $13 billion in new power lines will increase electricity bills by as much as $256 a year — and perhaps more if there are cost overruns.

"Albertans can't trust this PC government to protect their pocketbooks," said Mason.

"The PC caucus was informed back in 2010 about these looming cost increases. They ignored the facts and are still forging ahead with these massively overbuilt power projects."

Mason said it's time the province repealed legislation passed two years ago that allows the cabinet to approve power line construction without public hearings if it deems the lines are critically needed.

The New Democrats believe the rules are flawed because they allow the Tories to hand out what the NDP says are unnecessary transmission line contracts to party donors without competitive bidding.

Energy Minister Ron Liepert said the power lines are needed to serve a growing network of industrial and residential users, and to avoid brownouts.

Liepert said a lot of estimates are flying around, but the province relies on numbers from the Alberta Electric System Operator, the agency that is supposed to make sure power supply meets consumer needs.

He said operator figures show that "for every billion dollars of construction, it will be $1 (a month) on the residential bill."

"There's nothing new here."

Power price spikes have been a hot topic in Alberta. Some electricity bills soared as high as 65 per cent after power provider TransAlta shut down two of its aging turbines in December.

It said the units were nearing the end of their operational lives and it was not cost-effective to retrofit them.