The Wildrose Party's utilities critic says Monday’s rolling blackouts across Alberta seem "suspicious."

Joe Anglin says the province needs to investigate why six power generators — four coal and two gas burning — stopped working as temperatures in the province climbed past 30 C.

"The odds of that happening are suspicious. They really are," said Anglin.

"Imagine driving down the QE II and getting four flat tires, simultaneously for four different reasons. What are the odds? So, clearly we need to look into this — and we need to look into with a view of price manipulation because prices did hit a $1,000 per mega watt," he said.

The rolling blackouts highlight the failure of the Conservative’s market-based model for electricity, said NDP MLA David Eggen.

The Alberta Electric System Operator (AESO) and Epcor have stated that demand was not particularly high, Eggen said, but AESO said Tuesday that soaring temperatures drove Alberta's demand for electricity to an all-time summer high of 9,885 megawatts during the hour of 2 p.m. on July 9.

"This increased demand, coupled with the unplanned outage of four coal-fired and two gas-fired generators, created a need to reduce electricity consumption across the province," said the AESO in a release. "The all-time record high for Alberta's electricity demand is 10,609 MW set on January 15, 2012."

But Eggen said questions still remain.

"We must have a report on why those four plants were down yesterday, or on whether there was any illegal manipulation of the system to jack up prices, or on why power companies can build a plant anywhere and we just have to build transmission to work with those plants," he said.

Wildrose Party Leader Danielle Smith agreed with Eggen.

"We can't develop a solution until we know the problem," she said.

The power went out without notice, catching cities and electrical utilities off guard as traffic lights went dark.

"That's unacceptable," said Edmonton Mayor Stephen Mandel. "We'll have to find what happened."

"We have a process on emergency preparedness that these kind of things should be presented and information should be gotten out right away so we can get police to corners and make sure proper controls are put into place."

Alberta Energy Minister Ken Hughes told CBC News his department will also review the blackouts, adding that such occurrences are rare.

He also said the event makes the case for more transmission lines in the province, though he acknowledged the blackouts were not due to any congestion on the province's electricity grid.

But Smith said her party believes it doesn't matter how many power transmissions there are, if the plants go offline then "the lights go out."

She said Alberta needs to diversify its power supply, including more natural gas plants.

AESO president Doug Simpson said there’s no reason to conclude there are problems with the system.

"We're planning, we're forecasting, we're keeping an eye on things. We're fully maximizing our inter-ties with our neighbours so we can import power. So hopefully we're prepared so we can avoid this again," he said.

Three of the four coal-burning plants were back online by Tuesday morning.

The AESO plans to review what caused the plants stopped working.

But those findings won't be released to the public because of Alberta's competitive electricity market, officials said.