Professor Demurs: ‘Well-To-Wheels’ Efficiency Twice As Great In Electric Cars


Professor Demurs:
Efficiency Twice As
Great In Electric Cars

To the Editor:
In his Jan. 24-25 column, former DEC Commissioner Mike Zagata makes an argument that is theoretically interesting but falls apart when you look at the actual numbers behind it.
Zagata compares electric cars to conventional gas-powered vehicles and points out that, while electric cars are responsible for lower carbon emissions during the driving part of their life cycle, it’s more energy intensive to manufacture them.
This sets up a kind of decision that’s familiar to business people or households: Should I go for Option A that’s more expensive to buy but cheaper to operate, or Option B that’s cheaper off the shelf but costlier to use?
It’s a good question to ask, and most people would then want to know how much cheaper is Option B to buy, and how much more expensive to operate?
Mr. Zagata doesn’t ask that, but instead jumps right to his preferred conclusion: Electric cars are a bad idea.
It turns out people have run the numbers, and Mr. Zagata’s claim is wrong. The higher carbon emissions during manufacture are easily made up for, and more, by the lower carbon emissions while driving. And that’s true even if you don’t recycle the battery, so recycling makes the case for the electric car even stronger.
And it’s true even if your electricity is from coal.
An electric car is 80 percent to 90 percent efficient in terms of turning the electricity in the battery into the car’s motion. A gasoline-powered car ranges from 0 percent (when it’s idling) to 30 percent.
By the time you figure in additional considerations, like the energy lost in generating the electricity (assuming it’s from a coal- or gas-fired plant), or the energy spent pumping, shipping, and refining the oil that powers a conventional car, the “well-to-wheels” efficiency of the electric car is about 28 percent, while a gasoline car comes in around 14 percent. That difference is what allows electric cars to make up for the slightly larger impact they have during manufacturing. And if the electricity comes from cleaner sources than coal or gas, so much the better.
Mr. Zagata tries to score another zinger by pointing out that people will tend to charge their electric cars at night due to rates being lower, but that solar panels aren’t operating at night, so people are preferentially charging their clean electric cars with dirty coal-powered electricity. he hasn’t thought through the economics of the question.
Nighttime electric rates are lower now because our system is so reliant on large coal and nuclear units that are expensive to ramp up and down as demand goes up and down. It’s more efficient to leave them running through the night and sell the electricity for cheap than to turn them off and back on, so that’s what the power companies do.
If we were ever to get to a place where a lot of our electricity came from solar power, prices would shift to make it cheaper during the day when supply is abundant, and more expensive at night when we’d be pulling electricity from storage.
People would charge their cars during the day, perhaps with new charging stations installed in parking lots and at worksites. People who weren’t using the cars for a few days could even contribute to system-wide storage, loading up the battery during the day with cheap solar power, and letting the system take it back at night at a higher price.
Lastly, having an electric car means fewer parts to maintain, and therefore less chance of a faulty engine. Subsequently, this means that fewer lemons will be floating around in the market, which will save many people a lot of frustration. Currently, certain car brands, like Chevrolet and Dodge are causing some people to stress due to badly manufactured cars. Luckily, if your Dodge is a lemon, for example, you are able to contact an attorney to help you with a law case, but it’s hoped that the sale of electric cars will prevent the continued sale of lemons.
Mr. Zagata made one true claim: There is no one “silver bullet.” If someone thinks, “This one thing will solve our problems of energy supply and climate destabilization!”, they don’t understand the nature of the problem.
But careful analysis shows that electric cars are a useful part of the solution.
It’s strange Mr. Zagata puts so much effort into trying to convince you otherwise.
(The numbers here are from “Well to wheels: electric car efficiency,” by Maury Markowitz, February 22, 2013, at


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