Monday, March 11, 2013

Electric Cars, a Dirty Shade of Green

...A 2012 comprehensive life-cycle analysis in Journal of Industrial Ecology shows that almost half the lifetime carbon-dioxide emissions from an electric car come from the energy used to produce the car, especially the battery. The mining of lithium, for instance, is a less than green activity. By contrast, the manufacture of a gas-powered car accounts for 17% of its lifetime carbon-dioxide emissions. When an electric car rolls off the production line, it has already been responsible for 30,000 pounds of carbon-dioxide emission. The amount for making a conventional car: 14,000 pounds.
The Fisker "Karma"
From the start, an all electric vehicle has already produced double the amount of CO2 as a similar gas burning car. But surely, by not burning any gas at all, it will quickly catch up, right?  Not so fast.
While electric-car owners may cruise around feeling virtuous, they still recharge using electricity overwhelmingly produced with fossil fuels. Thus, the life-cycle analysis shows that for every mile driven, the average electric car indirectly emits about six ounces of carbon-dioxide. This is still a lot better than a similar-size conventional car, which emits about 12 ounces per mile. But remember, the production of the electric car has already resulted in sizeable emissions—the equivalent of 80,000 miles of travel in the vehicle.
The Tesla "Roadster"
Once you've driven the electric car 80,000 miles, it just starts to produce half the carbon emissions as a gas passer.  And that's about the life span of the lithium batteries (about 100,000 miles), and once you plug in a new set of AAs into the the thing, you're back in the carbon hole.  Meantime, my '97 Subaru has racked up 160,000 miles with no end in sight.
So unless the electric car is driven a lot, it will never get ahead environmentally. And that turns out to be a challenge. Consider the Nissan Leaf. It has only a 73-mile range per charge. Drivers attempting long road trips, as in one BBC test drive, have reported that recharging takes so long that the average speed is close to six miles per hour—a bit faster than your average jogger.

To make matters worse, the batteries in electric cars fade with time, just as they do in a cellphone. Nissan estimates that after five years, the less effective batteries in a typical Leaf bring the range down to 55 miles. As the MIT Technology Review cautioned last year: "Don't Drive Your Nissan Leaf Too Much."
The Nissan "Leaf"
A marathon runner should just dispense with the car and jog and not wear out the battery.  That leaves me out.
If a typical electric car is driven 50,000 miles over its lifetime, the huge initial emissions from its manufacture means the car will actually have put more carbon-dioxide in the atmosphere than a similar-size gasoline-powered car driven the same number of miles. Similarly, if the energy used to recharge the electric car comes mostly from coal-fired power plants, it will be responsible for the emission of almost 15 ounces of carbon-dioxide for every one of the 50,000 miles it is driven—three ounces more than a similar gas-powered car.
The Chevy "Volt"
I often ask people who buy electric cars around here how much they like their coal burning car.  They usually don't get the joke.  But to be fair, a small fraction of the regions electricity is produced by nuclear and other cleaner processes.
Even if the electric car is driven for 90,000 miles and the owner stays away from coal-powered electricity, the car will cause just 24% less carbon-dioxide emission than its gas-powered cousin. This is a far cry from "zero emissions." Over its entire lifetime, the electric car will be responsible for 8.7 tons of carbon dioxide less than the average conventional car.

Those 8.7 tons may sound like a considerable amount, but it's not. The current best estimate of the global warming damage of an extra ton of carbon-dioxide is about $5. This means an optimistic assessment of the avoided carbon-dioxide associated with an electric car will allow the owner to spare the world about $44 in climate damage. On the European emissions market, credit for 8.7 tons of carbon-dioxide costs $48.
We just moved a ton of leaves out of the garden (at least it felt that way).  If I could preserve them forever, could I get $5 (making the crude assumption that they're 100% carbon, and their not)?  It's not worth the trouble.

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