A new plan by the Ontario Power Authority calls for the provincial government to spend $26.5 billion on nuclear power plants to ensure the province's electricity supply until 2025.

The plan, released Wednesday, also increases the amount of conservation and hydroelectric power that the authority thinks can be achieved.

It was submitted to the province's energy regulator, the Ontario Energy Board, which will hold hearings to evaluate the plan's $60-billion overall spending projections and allow the public's input, the OPA said.

An environmental impact assessment will be included in the review.

Energy Minister Dwight Duncan announced in June 2006 that the province would likely build two new nuclear reactors. In May 2007, the government announced it had hired consultants to conduct a $3-million study of available nuclear reactor technology.

But the OPA plan said the province may need to build more new nuclear plants than the two reactors already on the books. The new plan would depend, among other things, on whether the reactors at the Pickering B nuclear site can be refurbished or must be replaced.

Plan plots closure of province's coal plants by 2014 

The OPA plan also proposes doubling the amount of renewable energy on the grid by 2025 and phasing out coal-fired generation by the end of 2014.

Opposition parties have lambasted Premier Dalton McGuinty and his Liberals for breaking a 2003 election promise to shut down all of the province's four coal-fired plants by 2007. The Liberals pushed back the deadline, eventually to 2014.

The government has acknowledged its disappointment with failing to meet the 2007 deadline, but has said the delays were necessary to deal with energy demands.

Amir Shalaby, OPA's vice-president of power system planning, said reduced consumption by homeowners across the province is the plan's cornerstone to counter the rising average cost of electricity, which he estimated could increase by 25 per cent.

"We project that an average household in Ontario would use 20 to 25 per cent less electricity by the end of this planned period than they do today," Shalaby said. "The plan, and the OEB review and approval process, will help Ontario define its choices further."

The OPA was established by the government in 2004 to plan the province's future energy supply.