Electric cars’ benefit not as great as claimed

April 6, 2014

(MORRISON COUNTY RECORD) – Are you impressed with the Tesla electric automobile? What impresses you? Is it the $70,000 price tag or the fact that the car reputedly produces zero emissions?

by Peter Vogelgesang

How could it produce emissions? It has no exhaust pipe. It runs on clean electricity.

Whoa. Where does the electricity come from? From batteries contained in the car. But what charges the batteries? The batteries are charged when you connect the charger in your garage to the batteries in the car, probably overnight. Where does the charger get electricity? From the municipal power plant that furnishes electricity to your community. Does the municipal power plant emit pollutant gasses? You bet. Big time. Especially if it is a coal burning plant and 50 percent of the power plants in the U.S. are coal burners.

cartoon-how-electric-cars-work

Did you know that a lead-acid  battery is only 40 percent efficient? In other words, the electric car can recover less than half of the electrical power put into the batteries. Combine this loss with the transmission line and transformer losses of the electrical distribution system, and we find that the electrically powered automobile has a thermal efficiency less than that of a gasoline-powered car. So which one is the greater polluter?

The difference, of course, is that the pollution from a gasoline-powered car is released in the city where we drive it, where we can see and smell the exhaust; whereas pollution from an electric power plant is released in the countryside through a tall smoke stack where it is out of sight and out of mind. But, if it is the overall pollution of the atmosphere that concerns us (global warming); the electric car can be a greater offender than the gasoline powered car.

Further, if our transportation system were to convert heavily to electrically powered vehicles, the electrical infrastructure across the nation would have to be greatly expanded, and that ain’t cheap.

Finally, if it is the reputed high performance of the Tesla automobile that may inspire you to buy one (for $70,000), fine. But if you are motivated to buy one because you believe you are doing good for the environment — forget it. Look for the source of the power that moves anything. If it originates from burning coal, then you are doing the worst that you can do.

Peter Vogelgesang is a Little Falls resident and  former staff scientist, retired from the research laboratories of 3M in Maplewood.

 

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