Tuesday, April 25, 2006

Feel free to copy, there is no copyright on an Anoneumouse montage. (click on image to enlarge)

Second law of thermodynamics

David cameron was trying out the latest green cars as part of his campaign to plug green Conservatism, and that meant abandoning anything approximating to dignity to take the wheel of the Noddy car, otherwise known as the G-WIZ, a battery-powered, plastic offering from India. The Daily Telegraph

Obviously he isn't aware of the Second law of thermodynamics

Electric cars use lead-acid batteries for storage. You plug your car into the wall at night and charge up your batteries, and then discharge them again while driving.

Charging batteries is extremely inefficient; electricity is used to create a chemical potential in the battery, but most of the electricity is converted to heat. And when the battery discharges again, a lot of the energy stored in it also heats the battery.

If the original electricity was created by burning gas or coal, then what this means is that a lot more CO2 is released per passenger mile by the battery-based electric car than by a petrol car.

You need to generate the energy actually consumed to move the vehicle, but also all the energy which was wasted in transmission and in charging and discharging the batteries, which means you need to burn more carbon at the power station than a car would have needed.

Lashings of Ginger Beer!


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