In his first week in office, U.S. President Barack Obama announced that his administration would let states independently regulate fuel efficiency standards. This gives unprecedented power to states like California to transform the North American auto industry, which will have a tremendous influence on the cars we drive here in Canada.

With a new imperative on Detroit (spun to appear as enthusiasm), the Big Three are finally getting on track with new electric models, electric/gas hybrids, and even electric/diesel hybrids. Many people share skepticism about hybrids and electric cars because, of course, electricity does not come free. Cars that run on electricity do not produce greenhouse gases during operation, but the production of the electricity to charge batteries certainly does. With this in mind, we thought it would be a good time to look at the question of what cars make sense from an environmental standpoint.

A good starting point for comparing vehicles is the GREET Model (Greenhouse gases Regulated Emissions and Energy use in Transportation) developed by the U.S. Department of Energy’s Argonne National Laboratory. This model allows you to consider many different “well-to-wheel” scenarios for energy generation, delivery, and fuel use. Too many to fit into a short article like this.

But, in brief, running scenarios for passenger cars and assuming the United States’ current energy portfolio (how they generate electricity), electric cars do outperform conventional gasoline-powered cars, using about 60 per cent of the energy, and producing about 70 per cent of the greenhouse gases.

Of course, your new Mustang or Charger is not a one-trick pony. Too often we think of the environment only in the context of greenhouse gases. Diesel and gas cars do outperform electric cars in terms of sulfur oxide (SOx) and fine particulate matter production in the U.S., mostly due to the large number of coal-fired plants in the U.S. Oxidized sulfur compounds in the atmosphere cause acid rain and fine particulate matter contributes to respiratory diseases.

So far, we have been talking about a U.S. context, and it is worth putting this all into a Canadian context. We have a very different energy portfolio, using more hydro- and nuclear-generated power. In 2003, Canada produced about one-third the CO2 per MWh, meaning that operating an electric car here might produce 20 to 30 per cent of the greenhouse gases generated in operating a gasoline-powered car. The disparity grows even larger when considering the carbon-intensive extraction of oil-sands petroleum.

So, what does this all mean? Conventional gasoline engines are the worst of the lot, no surprise there.

Here in Canada, go ahead and buy that hybrid or new electric model and feel comfortable that you are making a sound decision for the environment. However, the surprise is that, given the current energy portfolio in the United States, gas hybrids can only beat diesel cars for energy efficiency and greenhouse gas production if you run on the electric motor more than 50 per cent of the time. Even then, these hybrids will be responsible for more SOx and particulate matter in the atmosphere. Although these same hybrids would outperform diesels in Canada’s power mix, the auto industry should be building and marketing more diesel models given the infrastructure realities to our south.

– Sophia Dore is an environmental scientist with Conestoga-Rovers & Associates. Andrew Laursen is an assistant professor at Ryerson University.