A set of new rules for generators is set to be published early in 2011 and would go into effect in 2015, he said.

New coal plants could be built under the stringent emissions standards of the proposed rules, but companies would be prohibited from making investments to extend the lives of existing plants unless emissions levels can be reduced to levels equivalent to those of a natural gas-fired, combined-cycle plant.

According to Calgary-based generator TransAlta, the rules would require that coal plants be retired after 45 years of operation, or at the end of the end of current power purchase agreements--whichever is later.

Some 19% of Canadian power generation is currently from coal-fired plants.

TransAlta urged the government to take its time on the rules and requesting that carbon capture and sequestration for coal plants be allowed under the rules.

"We need to also make sure this transition is done in a careful and orderly fashion to maintain the critical reliability of our electricity infrastructure," said TransAlta CEO Steve Snyder.

"There is still a lot to do to ensure that Alberta's electricity system can make this transition in an efficient and equitable manner," he said.

TransAlta owns about 3,312 MW of coal-fired generation in Canada. It owns all or a percentage of four coal-fired plants in Canada. All of those plants are in Alberta. The company also owns the 1,376-MW Centralia coal-fired plant in Washington state. Overall, TransAlta owns 5,029 MW of capacity in Canada.

Canada is taking the steps in order to comply with its commitment to the Copenhagen Accord, which calls for a reduction of its greenhouse gas emissions by 17% below 2005 levels by 2020.

--Pam Radtke Russell, newsdesk@platts.com