Thursday, February 01, 2007

 

The False Promise of Electric Cars

Tom Whipple over at Falls Church News-Press writes some good stuff, especially on peak oil. But I have to take issue with his latest offering, “The Peak Oil Crisis: The Age of the Electric Car.”

Obviously, lots of people are hoping that the car culture can be saved. Without motor vehicles and the mobility we now enjoy, modern economies would come crashing down virtually overnight. So the search for something — anything — to keep our cars and trucks on the road becomes more desperate as time goes on.

We’ve heard it all before, of course: Electric cars are non-polluting, drive right past the gas station, blah blah blah. I’m surprised that Whipple, who is Mr. Reality when it comes to the topic of peak oil, would be so easily duped by the false promise of electric cars.

Time for a reality check. How much energy and resource consumption, environmental damage, and exploitation go into each car up to the point it rolls off the assembly line? Is that going to change just because the car has batteries and electric motors instead of an internal combustion engine? Not on your life. And where will the electricity to charge the batteries come from? You can put up PVC panels and windmills until the land is littered with them, and you are not going to have nearly enough electricity to run a fleet of millions of electric vehicles. What next? More nuke plants? No, thanks.

All kinds of straws are offered to us for grasping. Cars will run on electricity, ethanol, hydrogen, and — what next? — perpetual motion? But all these have serious problems, and by no means can replace oil. Ethanol’s energy balance is barely positive, even if we do our calculations charitably. Hydrogen, which is often mistakenly thought of as an energy source, is a definite energy sink. And electricity? This too is an energy sink! Batteries are just a form of storage, like hydrogen. Every time you convert energy from one form to another, you lose some of it. Let’s say you have a battery-powered electric car that you charge by plugging into the outlet at night. There is a transmission loss that occurs when sending power to your residence, the loss when converting electrical energy to chemical energy (charging), the loss when converting chemical energy back to electrical energy (discharging), and the loss when converting electrical energy to mechanical energy (making the car go). Now that’s a lot of loss.

The energy densities of batteries are far below that of oil, which has built and powers modern economies. Hydrogen has high energy density, but is a storage medium and energy sink. Ethanol has about two-thirds the energy by volume as gasoline, but it requires a big oil input to make it. Are these sources going to keep the petroleum civilization going? Fagettaboutit.

I hope Tom Whipple keeps writing about peak oil. But I also hope he looks more closely at the false promise of electric cars.



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