Premier Kathleen Wynne evaded questions Tuesday about when cabinet ministers knew the cost of cancelling the Oakville gas plant would far exceed the $40 million touted by the government, blaming continually changing figures provided by the Ontario Power Authority.

Wynne made the statement in an appearance before the legislature’s justice committee, which is holding hearings into the decision to cancel the Oakville and Mississauga plants ahead of the 2011 provincial election.

Wynne appeared at the committee hours after the CEO of the OPA revealed that the cost of scrapping the Oakville gas plant was $310 million -- eight times more than the Liberal government had been telling taxpayers.

OPA CEO Colin Andersen dropped the bombshell during his testimony Tuesday morning.

Andersen said that the $40 million figure only represented “sunk costs,” and there were elements in the project memorandum that did not have dollar figures assigned to them.

Andersen told reporters after his testimony that all parties to the agreement, including government ministers, knew the costs would be higher.

“Some of the numbers were known at the time, but the MOU outlined a number of other categories of expenditures as well,” Andersen said. “It didn’t have a number attached, but everybody knew it would be over and above $40 million in some costs.”

When asked at what point the government knew the cost to cancel the plant would be higher, Andersen replied: “They knew from the outset that there were going to be additional costs.”

In her testimony Tuesday afternoon, Wynne said she was told by her staff last month that the OPA’s figures “kept changing,” with the cost to relocate the Oakville plant to Napanee pegged at between $33 million and $136 million. Wynne said in light of Andersen’s testimony, it’s clear that the auditor general’s review is required to confirm the real figure.

“I believe that the complexity and the fact that the OPA numbers keep changing justifies my decision to call in the auditor. We need to wait for the auditor general’s report,” Wynne said in her opening statement.

She also said that any time she cited a figure publicly, “that has been the number that I have understood to be the real number.”

Asked repeatedly by Progressive Conservative energy critic Vic Fedeli when cabinet ministers knew the cost of relocating the Oakville plant would exceed $40 million, Wynne first said there has been “a lot of confusion” about the numbers. She then admitted that while $40 million represented the sunk costs, “we also understood that there would be other costs associated with that, as I know you know, from the memorandum of understanding.”

Wynne also testified that she was not involved in the controversial decisions to cancel the gas plants in the lead-up to the 2011 election, despite her role as campaign vice-chair.

Wynne said she first learned of the decision to cancel the Mississauga facility via media reports. The premier testified that the plants were scrapped due to opposition to the projects in both communities.

“The siting of these two plants failed to take into account the feelings of the community,” Wynne said. “Despite expert advice, despite an open procurement process and all the decision points along the way, the overall process failed. I’ve been very clear that I regret that we didn’t have a different process in place.”

After Andersen’s testimony Tuesday morning, Progressive Conservative House Leader Jim Wilson accused Wynne of using a dollar figure during discussions about the plant in the legislature “that you knew was not the whole truth.

“Colin Andersen said just a few minutes ago downstairs in committee that everyone knew, that everyone knew the true cost and it was much higher than the Liberal Party and you yourself have admitted,” Wilson said during question period.

Energy Minister Bob Chiarelli countered that the details about higher costs were contained in reports that were available for anyone to review.

“The whole world knew there were additional costs,” Chiarelli said during question period. “There was a 216 page contract, and if he didn’t read it in Sept. 2012, that’s his problem. Do your job right.”

After question period, NDP energy critic Peter Tabuns said the new figures prove the government has “misled the public.”

“The premier hasn’t been open and transparent with the people of Ontario, it’s as simple as that, and she’s going to have to answer for that this afternoon,” Tabuns told reporters before Wynne’s appearance at the committee.

Fedeli said the government has “been deceiving us right from day one,” and accused the government of a cover-up.

“I think (Andersen) nailed it with the final two words of the testimony: everyone knew. Period. The government knew, the premier knew, Kathleen Wynne in cabinet knew. Everybody knew that this thing was far more than $40 million,” Fedeli told reporters.

In a recent report, Ontario’s auditor general revealed that the cost of cancelling the Mississauga plant was $275 million, $85 million more than the government claimed.

That puts the cost so far of cancelling the two plants at $600 million.

The auditor general’s report into the Oakville plant is expected in late summer.

PC Leader Tim Hudak moved a non-confidence motion against the government over the gas plant issue on Monday. However, the move is largely symbolic because the Liberals will not call for a vote.

With a report from CTV Toronto’s Queen’s Park Bureau Chief Paul Bliss