Ontario's long term electricity supply mix plan effectively imposes a "nuclear ceiling" over renewable energy development in the province, says a new report from the Pembina Institute, an environmental think tank based in Alberta. Ontario energy minister George Smitherman announced in September that he wanted system planners at the Ontario Power Authority (OPA) to review and "tweak" its 20-year integrated power system plan with the goal of accelerating conservation efforts and adding more renewable energy to the electricity mix. But the Pembina report, Plugging Ontario into a Green Future, argues those efforts will be hindered by the plan's focus on large, centralised nuclear generators. It recommends the province replace aging nuclear stations with renewable energy resources. The provincial government's first opportunity to do that will come in early 2009, when it must decide whether to rebuild or replace the Pickering B nuclear plant, made up of four 540 MW reactors scheduled to come offline between 2013 and 2016. A similar decision about the Bruce B nuclear plant, made up of four 850 MW units, will also have to be made within the mandate of the current government. The Pembina report, released by a coalition of environmental groups, recommends the province opt for stronger conservation efforts and controlled prices for renewable energy instead of pursuing the nuclear option. "The question is whether the OPA can review this plan with new eyes and an open mind. If not, we are headed for more of the same," says Greenpeace's Shawn-Patrick Stensil.