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Posted on September 24, 2014

Electric Vehicles Widen Their Clean-Air Advantage

By Jonathan Marshall

If you doubt that electric vehicles (EVs) will play a big part in the future of clean transportation, check out a new analysis from the Union of Concerned Scientists (UCS), which shows EVs increasingly undercutting even the most efficient hybrids in terms of heat-trapping emissions of greenhouse gases.

Electric drives generally make more efficient use of energy than internal-combustion engines, but critics have long pointed out that they are only as clean as the electricity that powers them. Electric vehicles in states that mostly use coal-fired power may in some cases be a bit less clean than the most efficient gasoline-powered hybrids, like the Toyota Prius.

That’s not true in PG&E’s service area, where more than half the electricity that customers use comes from sources that emit no greenhouse gases. Those sources include clean hydro and nuclear as well as renewable energy. In 2012, PG&E’s rate of CO2 emissions was only about a third of the national average for utilities. The utility isn’t resting on its laurels; this year it’s on track to supply about 27 percent of its electricity sales from renewable sources, up from less than 20 percent in 2012.

According to the UCS study, a gasoline or diesel-powered vehicle in California would need to beat 95 miles per gallon to beat an EV when it comes to greenhouse gas emissions. That’s a pretty high bar to say the least; the Prius gets just a little more than 50 miles per gallon. (Of course, hybrids offer other advantages, including longer range between refueling.)

The good news is that the emissions advantage for electric drives is widening thanks to cleaner power emissions in many states and gains in the efficiency of new plug-in vehicles. For example, the UCS study cites a 12 percent improvement in the operating efficiency of the Nissan Leaf (the amount of electricity consumed per mile of travel), thanks to better braking, aerodynamics and heating.

As a result, the UCS study concludes, 60 percent of Americans now live in areas where in areas where EVs have the edge over the best hybrids. That compares to 45 percent just three years ago.

Today’s figure is probably even better than 60 percent, UCS notes, because its study doesn’t reflect the very latest data on the growth of renewable energy nationwide.

Moreover, even in the worst-performing state, Colorado, the emissions attributable to a typical EV equal those from a gasoline-powered car rated at 34 miles per gallon. That’s not too shabby, considering that the average new car today gets about 28 miles per gallon.

Note that California just passed an historic 100,000 milestone this month for sales of EVs since 2010. And PG&E last week announced the latest additions to its growing fleet of EVs, including one truck with the unique ability to export enough power to keep a neighborhood lit while crews make local electric repairs.

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