Tuesday, April 8, 2014

Many 'green' cars carry greenhouse gas

America’s electric cars are better for the environment, but they share a dirty little secret.

The Chevy Volt, Nissan Leaf and Tesla Roadster all use a super greenhouse gas known as HFC 134a as the refrigerant for their air conditioners. The liquid coolant is so potent that when it leaks into the atmosphere, it traps 1,400 times more heat than carbon dioxide over a 100-year time horizon.

For automakers and advocates of green transportation, it poses an uncomfortable truth: Vehicles touted as a solution to climate change carry a hairspray-sized canister loaded with a chemical that significantly contributes to warming of the earth’s climate. As much as half of current HFC emissions, a small but fast-growing source of global warming pollution, come from leaks out of the air conditioners in cars.

Already a number of Chevrolet, Buick, GMC and Cadillac gas-powered cars use an alternative climate-friendlier coolant called HFO 1234yf, as carmakers confront growing pressure from environmentalists and as regulations are developed by governments. Climate experts say it’s clear that all electric automakers should get on board soon. “It makes sense for electric vehicles to use (alternatives), and to reduce their overall global warming potential,” said Don Anair, deputy director of the clean vehicles program at the Union of Concerned Scientists, a science advocacy group.

But among 16 EV models on America’s roads, only two — Chevy’s newest model of its all-electric Spark and the leasable Honda Fit — have ditched the super greenhouse gas HFC 134a for the climate-safe alternative so far.

Many automakers of both electric cars and conventional ones have expressed reluctance to commit to the switch, citing the cost and limited supply of new alternatives. The European Union has banned HFC 134a for any newly redesigned or re-engineered vehicles this year, and for all vehicles in 2017 — though the industry elsewhere is not rapidly adopting the EU’s lead. The United States has no such mandate yet. The U.S. Environmental Protection Agency is considering one.

How countries got to this point is a classic case of unintended environmental consequences. Under the Montreal Protocol, a 1987 treaty that zeroed out substances harmful to the earth’s ozone layer, HFC 134 was chosen by nations as the best alternative at the time to replace ozone-depleting CFCs. The result today is that most of the billion or so cars on the world’s roads use the HFC refrigerant — but while the ozone layer has rebounded, HFC 134a is exacerbating the global warming problem.

So far, HFC 134a and other types of hydrofluorocarbons have contributed to less than 1 percent of total global warming, according to a study published in the Atmospheric Chemistry and Physics scientific journal. But the use of these damaging gases is climbing generally, as developing world economies use and produce more HFC-spewing cars, air conditioners and refrigerators, and as they make more foam insulation that uses the chemical during manufacture.

Emissions from HFCs are growing at a rate of 10 to 15 percent per year, the study says. Left unchecked, HFCs alone could add up to 0.5 degree Celsius of the global average temperature rise by the end of the century, about a quarter of the 2 degree Celsius rise that nations are struggling to stay within through international agreements.

Electric vehicles are touted for producing zero tailpipe emissions and being a critical force in reducing fossil fuel use and curbing climate-changing pollution — which could make their use of the super greenhouse gas HFC 134a all the more hypocritical.

The Chevy Volt, Nissan Leaf and Tesla Roadster represent about two-thirds of the roughly 180,000 EVs sold in recent years in the United States.

Kevin Kelly, a spokesman for General Motors, wouldn’t say if or when the hybrid Chevy Volt, the biggest-selling U.S. EV, might switch to HFO 1234yf.

The auto giant in 2010 said it would be the first U.S. carmaker to voluntarily phase out HFC 134a from many of its passenger cars. So far, only its Chevy Spark EV, which had sold 703 units as of February, and its conventional Cadillac XTS luxury sedan use the new refrigerant. Kelly declined to disclose which other GM models have or will soon follow suit.

Spokespeople for Nissan Motors in the United States were not immediately able to provide more information. Tesla Motors did not respond to repeated requests for comments.

David Doniger, a policy director at the Natural Resources Defense Council who has worked on ozone issues since the 1980s, noted the hypocrisy, but said he is “more concerned about getting the overall transition to occur as quickly as we can.”

All car manufacturers “have the opportunity to switch refrigerants, and they should do it as quickly as they can,” he said. “From an environmental point of view, if you want to get the changeover happening at a large scale, I wouldn’t focus first on electric cars _ I’d just be focusing on volume.” Nissan Motors, for instance, sold 1.2 million gas cars in the U.S. in 2013 and just 23,000 all-electric Leafs.

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