Is your EV really so green?

The global shift from petrol-fuelled cars to EVs is considered a huge part of both severing the world’s dependence on fossil fuels and reducing greenhouse gas emissions. At least that’s what the International Energy Agency said last year, in its Technology Roadmap for Electric and Plug-In Hybrid Electric Vehicles; part of its series outlining some of the most important technologies needed for achieving a global energy-related CO2 target in 2050 of 50 per cent below current levels.

In its report, the IEA presents “a detailed scenario for the evolution of these types of vehicles and their market penetration, from annual production of a few thousand to over 100 million vehicles by 2050,” and describes the next decade is a “make or break” period for EVs and PHEVs, “to ensure that the rapidly growing consumer market is ready to purchase them.” And according to a new study by ABI Research, sales of hybrid EVs are set to exceed 8.3 million in 2020 (about 11 per cent of all new vehicles sold), after what the research group has described as “a significant year” in 2011, for the introduction of the first consumer plug-in electric vehicle and battery EV models from major manufacturers, along with promises of more in 2012.

But what if it turned out that switching to EVs didn’t actually lower your carbon footprint? Or worse, what if the associated carbon emissions were even greater than than those from driving a conventional, internal combustion engine automobile? For the most part, this is a highly unlikely scenario. But an investigation by Pike Research analyst John Gartner has turned up the interesting fact that in some states of America – go on, have a guess which – this is exactly the case.

Writing on Matter Network, Gartner says he was inspired to investigate the impact of location – and that location’s energy supply mix – on an EV’s ‘greenness,’ after the the release of the American Council for an Energy-Efficient Economy’s annual guide to the greenest vehicles. “For the first time, an electric vehicle (the Mitsubishi i-MiEV) ranked highest,” said Gartner. “This factoid stirred up for me an issue that is not discussed often enough, and is understood even less. When driving an EV, where you charge the batteries will determine whether or not the vehicle is greener than driving a gasoline car.”

Gartner cites EPA figures that say an EV powered by the average US grid emits about 207 grams of CO2 per mile, compared with the average new light duty vehicle sold in 2012, at 263 grams. “So on average, driving electric is greener than driving a 33 mpg car,” he says. And of course, in states with a mix that includes a lot of renewables or nuclear, “the carbon footprint of driving electric is clearly cleaner than your average automobile.” But, he adds, “in states where coal is still king, the carbon footprint of an EV can actually be worse.”

To illustrate this point, Gartner includes a graph that shows five states whose EV emissions work out to be  higher than those of a conventional car: West Virginia (282.2g of CO2 per mile); Kentucky (288.1g); Indiana (288.6g); North Dakota (289g); Wyoming (294.2g). And he says that the state by state breakdown is “the tip of the iceberg when it comes to understanding true EV emissions,” with significant differences in carbon density possibly between utilities within a state, and time of day that EV-users charge also playing a part in the generation mix.

And while Gartner concludes his observations by reasserting that, by-and-large, “you can be confident that going electric is better, from a carbon emissions standpoint, than driving your old gas-guzzler,” he also stresses that “our knowledge about how green the grid is at any moment in time is woefully inadequate.”

(The same may be true in Australia, particularly in states such as Victoria, which have a much higher carbon intensity because of its reliance on brown coal power stations. Interestingly, the Better Place network which is due to be rolled out in Canberra later this year, will purchase green energy from the local utility, ActewAGL, to reinforce its environmental credentials).

So, how green is your EV?