TORONTO - A new study suggests Ontario can cut greenhouse gases in half over the next 20 years and eliminate the use of coal at least five years sooner than planned without raising prices for consumers.

The joint analysis released Wednesday by the Pembina Institute and WWF-Canada involved re-crunching Ontario Power Authority data to come up with a greener model that incorporates tried and true renewable energy options.

The OPA plan seeks to eliminate coal power by 2017 while expanding Ontario's reliance on nuclear power.

But the environmental groups put forward a pair of "green" plans that will instead rely more on efficiency and conservation while greatly expanding the reliance on renewable wind, solar and hydroelectric power.

WWF-Canada's Keith Stewart says nuclear power is unreliable and costly and believes smaller, local renewable energy projects are more efficient.

Under the WWF-Pembina plan, energy costs to consumers are expected to be 11 per cent lower compared to the OPA's preliminary plan.