Electric cars: are they really more polluting than gas?

Most people think if you drive an electric car, then you are helping the environment.

But not if your electricity comes from a coal-fired power generation plant, according to a University of Toronto report.

• Electric cars could boost CO2 emissions in some provinces

In Nova Scotia, Alberta and Saskatchewan, electric cars generate more carbon over their lifetimes than gas-powered vehicles, Chris Kennedy, a professor of civil engineering at the University of Toronto, told CBC Radio's The Current last week.

That's because those provinces generate much of their electricity by burning coal, so consuming more electricity — by charging your electric car battery, for instance — significantly boosts carbon emissions.

For a given country or province, if average emissions are under 600 tonnes of CO2 per gigawatt hour, then switching from conventional to electric cars, buses and trucks will lead to a reduction in carbon emissions, Kennedy reported in a study published in the journal Nature Climate Change earlier this month. But anything over will not.

However, several experts in Nova Scotia say hang on: the numbers are from 2012 and don't consider renewable energy or what is about to come online in this province.

"I think Nova Scotia was pointed out rather abruptly because Nova Scotia is rather high on the greenhouse gas emitters list, but it failed to recognize the future in this province," says Lucas Swan, a professor of mechanical engineering at Dalhousie University. 

"It will be falling because we have the largest wind field coming online later this year. We have the big hydro project at Muskrat Falls that's going to come on in the next couple of years. All those things drive our emission intensity down." 

"My numbers to date right now, simple back-of-the-envelope calculations, show presently I am saving greenhouse gas emissions in Nova Scotia by driving an electric car over driving a gas car right now," he added. 

"It is a marginal amount, but it gets better every single year because we continue to add renewable energy to our grid."

Another expert, Lucas's father David Swan, says the report is correct in that Nova Scotia needs to wean itself off electricity produced by coal. But David Swan says the research fails to consider other problems.

"The problem we have in Nova Scotia is we have closed our refinery and all our gas-refined products are now imported. They come up the highway form Saint John or by barge from Houston," David Swan says. 

"We can continue to do that or we can elect to drive electric in the province and generate power by wind and other means."

Both of these engineers point out the take-home message from Kennedy's study is for governments to get their average emissions down.

And David Swan says it is about time Nova Scotia steps up and puts coal plants on the back burner.

"We are not a backwater," he says. "I hate that approach that we are behind, we are going to wait for other people to solve our problems. I think we can do it ourselves."