The sector also decreased its emissions of nitrogen oxide, sulphur dioxide and mercury because of new technology to clean up emissions, the report said.
The shutdown of Ontario's coal-fired plants contributed significantly to the reduction in greenhouse gas emissions and was "one of the largest climate change initiatives ever undertaken in North America," the association said in its report.
It estimates 45 tonnes of carbon-dioxide-equivalent emissions were eliminated by time Ontario Power Generation finished closing the Nanticoke plant in 2014.
The association, which represents both private-sector generators and public utilities across Canada (excluding Quebec Hydro), estimates the industry is now responsible for about 12 per cent of Canada's greenhouse gas emissions.
The reduction in emissions reflects a shift in the sources of power in Canada. There was 8.8 per cent less coal generation and 3.5 per cent less hydro in 2014 than in 2013.
The amount of nuclear generation is up 8.1 per cent, and renewable generation from sources other than hydro are up 6.9 per cent.
There was also a significant improvement in energy conservation, which reduced the need for new generation sources.
Association president Sergio Marchi, a former cabinet minister in the Liberal government of Jean Chretien, says members of the association are committed to reducing the gases that lead to climate change.
"These achievements, combined with the fact that over 80 per cent of Canada's electricity is already generated from non-emitting sources, will strengthen Canada's position at the upcoming Conference of Parties (COP) meeting in Paris later this year," he said in a release.
Canada has announced it will commit to reducing its greenhouse gas emissions by 30 per cent below 2005 levels by 2030 ahead of a significant climate accord expected to be signed in Paris this year.
The electricity industry is attempting to predict how climate change will affect its business long-term, the annual report says.
In 2014, 63 per cent of Canadian Electricity Association members identified climate change as an enterprise risk issue, as extreme storms, low lake levels, reduced snow pack and other effects play havoc with hydro generation and transmission lines.
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