Surprise: Electric Cars Not Actually Zero-Emission

eta-report-electric-shockThe findings you’re most likely to hear this morning from a new report by the European lobby group Transport & Environment include these three hot-button points: electric cars could increase carbon emissions, could “speed climate change,” and may not reduce oil dependency.

But a closer read of the report reveals its basic premise shouldn’t actually be that controversial. Electric cars have a role to play in reducing greenhouse gas emissions from transportation, the group argues. But the electricity supply will have to be cleaned up by adding renewables (like solar and wind) to the power grid (with a push from government), and the cars “must be more energy-efficient than state-of-the-art conventional vehicles on a ‘tank to wheel’ basis” (which they already are) in order to realize significant environmental benefits.

“Without a doubt,” the group writes, “electric and plug-in hybrid cars can help reduce CO2 emissions and oil consumption.” But surprise!: Electric vehicles won’t solve climate change. The cars don’t produce tailpipe emissions (thus, the common shorthand of “zero emission vehicle”), but they are only as clean as their electricity supply. “Electric cars powered by wind or solar energy are obviously superior,” in terms of well-to-wheel environmental impacts, Transport & Environment finds. “But if the electricity comes from coal, hybrids perform better.”

Cleantech venture capitalist Vinod Khosla raised a related point earlier this year in a talk at the AlwaysOn Summit. For years to come, he said, electric vehicles in the U.S., China and India will be “plugging into a lump of coal.

That said, some studies have found that even when plugging into a “dirty grid,” electric cars can result in fewer overall emissions than their gasoline-fueled counterparts because power plants burn coal more efficiently than cars burn gas, and can potentially be controlled more effectively.

The impact of electric vehicles on energy imports and emissions will vary by country. But for the U.S., the Pacific Northwest National Lab has found that switching about three-quarters of the national light-vehicle fleet to plug-in vehicles that charge at night, oil consumption could be slashed by 6.2 million barrels per day — eliminating more than half of imports, according to the Wall Street Journal.

powertrain-emissions-mckinseyIn analysis released last year, McKinsey & Company estimates that swapping out a gasoline-powered car in China, with its notoriously coal-fired grid, for a similar-sized electric model would reduce greenhouse gas emissions by 19 percent per car (see chart at left). That’s not enough, but it’s a start.

An important next step, the report’s authors argue, must be taken by government. They recommend three legislative actions: Long-term CO2 standards should be tightened for vehicles (new emission standards for vehicles in the U.S. are slated to be phased in with 2012 models); “strong post-2020 targets for renewable energy” should be set; and the “quantity and quality of electricity” should be measured with on-board metering.


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