Queen's Park has changed its mind about building a giant gas-fired electrical plant in Oakville, saying it is no longer needed.

"I'm tremendously pleased to announce, on behalf of the provincial government, that the proposed Oakville power plant has been stopped," local Liberal MPP Kevin Flynn told a hastily-arranged news conference in Oakville on Thursday.

Energy Minister Brad Duguid said the plant would not be moved to another location within the GTA.

The news delighted opponents of the project. They cheered the words of Flynn and Duguid.

"Total joy. Good decision. The best decision," said Carolyn Gagnon. "I'm absolutely thrilled that the government listened to the people and revisited this whole thing."

The government explained its rationale in a news release.

"Changes in demand and supply -- including more than 8,000 megawatts of new, cleaner power and successful conservation efforts -- have made it clear that this proposed natural gas plant is no longer required.

"A transmission solution can ensure that the growing region will have enough electricity to meet future needs of homes, hospitals, schools and businesses."

This has opposition parties screaming flip-flop.

“For more than a year, the government swore that the plant was absolutely necessary to meet growing demand for electricity,” NDP energy critic Peter Tabuns said in a news release.

“Now all of a sudden – coincidentally enough with an election looming – they say that there is more than enough electricity supply.”

Last November, the Ontario Power Authority wrote residents to tell them that residential consumption in Oakville was 10 per cent higher than in neighbouring Mississauga. It noted that gas-fired plants were operating in Mississauga, Toronto and Brampton.

The proposed plant, to be operated by TransCanada, would have generated 900 megawatts of electricity.

But it has met with strong, organized opposition in the affluent community of Oakville.

Citizens for Clean Air said the plant, to be located close to the existing Ford auto assembly plant, would be too close to residential areas and schools. The closest school would be about three football-field-lengths away.

A blast at a Connecticut natural gas-fired electricity plant in February left six workers dead.

While Premier Dalton McGuinty said in March the plant wouldn't be a safety hazard, Oakville's Mayor Rob Burton wanted the project shut down.

Flynn sided with the plant's opponents, who got a publicity boost last week when famous U.S. activist Erin Brockovich came to their community. She normally commands a speaking fee of $25,000.

Brockovich encouraged the opponents to keep pushing the government.

After her appearance, Duguid said the government was listening carefully and considering all options.

The government might not be off the hook. CTV Toronto's Paul Bliss reported that one source told him it's conceivable that TransCanada could sue for hundreds of millions of dollars over the cancelled project.

With a report from CTV Toronto's Paul Bliss