WINNIPEG, Manitoba, Jan 15 (Reuters) - The minister responsible for Alberta's electricity system said on Monday he has "high concern" about whether the Canadian province is building enough new power plants to avoid shortfalls, after frigid weather strained the grid.

The Alberta Electric System Operator (AESO) issued a grid alert on Saturday, warning consumers that it may impose rolling power outages due to soaring demand caused by extreme cold. Consumers responded by cutting electricity use and the grid avoided outages.

The system strain reflects in part Alberta's rush to phase out coal-fired electricity generation during the past decade, Alberta Affordability and Utilities Minister Nathan Neudorf said.

Power capacity "is still an area of high concern," Neudorf said in an interview. "As we saw this weekend, if you have a couple of plants go down due to the cold or mechanical issues you can be in a tough spot very quickly."

Conditions were a "perfect storm" for strained power supplies, Neudorf said, including little wind to generate electricity and limited ability for neighboring provinces to share power due to their own frigid weather.

Alberta last year halted approvals on renewable energy projects until March 2024 over concerns about intermittency and land use. Alberta generates most of its electricity from natural gas.

Alberta has added significant new electricity capacity in the last two years, however. Kineticor's 900-megawatt Cascade power project is expected to come online soon, capable of supplying 8% of Alberta's average electricity demand.

That plant alone will significantly ease future strains, said Sara Hastings-Simon, associate professor of science at the University of Calgary.

Saturday's grid alert highlights the need for Alberta to build more battery storage and to offer consumers lower electricity prices during off-peak periods, reducing potential for overwhelming the grid, Hastings-Simon said.

Alberta has threatened to undermine Prime Minister Justin Trudeau's clean electricity regulations, which aim to make Canada's power grid emissions-free on a net basis by 2035, a goal that Premier Danielle Smith says is unrealistic.

The regulations would strictly limit the hours natural gas plants can operate during peak demand times and require costly carbon-capture facilities, Neudorf said.

"We hope this (grid alert) is a life lesson for all Canadians," he said.

Spokespersons for the Canadian natural resources ministry could not immediately be reached.

AESO declared three grid alerts last year and seven in 2022. Alberta last imposed rotating power outages in 2013 during a major flood. (Reporting by Rod Nickel in Winnipeg, Manitoba Editing by Matthew Lewis)