Construction was well underway on the Mississauga gas plant when the Liberals quietly announced they were scrapping the project just days before the Oct. 6, 2011 election.
The government said it would cost $190 million to kill the project, a move the opposition parties called an expensive Liberal seat saver program.
The Progressive Conservatives and New Democrats used their majority on a legislative committee to demand the auditor general conduct an investigation.
"I really don't expect to see anything significantly different than the $190 million figure that the documents show Mississauga cost," PC energy critic Vic Fedeli said about the auditor's report.
"If there's anything different than that, that means there are other documents we don't have. In the 56,000 documents we do have, we show maybe $195 million."
However, the New Democrats believe the auditor general may uncover costs the Liberals have not disclosed for such things as new transmission lines and the delivery of natural gas to the site, items which could cost hundreds of millions of dollars.
"I really want to see the results of what I think are going to be a very rigorous assessment," said NDP energy critic Peter Tabuns. "I want to see if there were any side deals."
Premier Kathleen Wynne has already admitted it was a political decision to cancel the Mississauga gas plant and another one in neighbouring Oakville, which the Liberals scrapped in 2010 in the face of widespread local opposition.
Wynne was the Liberal campaign co-chair in 2011, but insisted she wasn't in on the decision to halt the Mississauga project.
"I was not in the room when the decision around the closure of the Mississauga plant was made, but I'm part of the government and I stand by those decisions," she said in the legislature last week.
The Opposition said it's the cancelled plant in Oakville that they're really interested in, and flatly rejected the Liberals' claim that scrapping it cost taxpayers $40 million. The auditor general is also investigating the cost of cancelling the Oakville project, which the Tories said they believe is closer to $1 billion.
"Premier Wynne knows the answers to the questions that we're asking. She knows how much money the real total is," said Progressive Conservative Peter Shurman.
"It would be a heck of a lot easier if the premier would stand up and own up and 'fess up and say 'here's what I know, here's what it cost' and take her just medicine, as opposed to drawing this thing out the way she is and waiting until next summer for us to find out that this cost a boatload of money."
Wynne has repeatedly offered to appear at the justice committee hearings into the cancelled gas plants and testify under oath, and said she's doing her best to make sure the opposition parties find out what they want to know.
"I will continue to work with my colleagues to make sure that every question that is asked is answered," she said.
However, the NDP said testimony at the justice committee last week showed Liberal political staff have been deleting gas plant documents requested by the committee.
"I don't think the Liberals are pursuing an open strategy," said Tabuns. "I think they're still doing everything they can to cover themselves."