Friday, January 15, 2010

The Volt's Electric Appetite.

Electric cars are being offered as die Wunderlösung to solve our transportation system's dependence on petroleum. But what would the wide-scale adoption of electric vehicles require in terms of increased electricity production?

We will take as a representative electric vehicle the Chevy Volt. The Volt is expected to operate such that it will consume 8 kW-hr to provide 40 miles of driving (which is a reasonable assumption for a day's mileage of a passenger car). The total distance driven in passenger cars and light trucks in the United States in 2008 was about 2.4T miles. If half of that distance were to be driven in Chevy Volts, the total required electricity to support this yearly travel budget would be about 240M MW-hr.

Note that the total electricity generated in the US in 2008 was about 4.2B MW-hr, so we would need to increase our generation capacity by about 6% to support the widespread use of electric vehicles. In terms of electric-power generation plants, this would mean we would need to build either 20 new nuclear-fueled plants, or 60 more coal-fired plants. This is a substantial investment in infrastructure; a typical coal-fired power plant runs about $1B to build. By the way, using the effective yearly output from a 2MW wind turbine, the number of turbines one would need to provide this electricity would be about 40,000 at a cost of about $120B just to install the turbines. Good luck with that.

One could argue that the energy needs for electric vehicles could be met with the present inventory of generating plants combined with an diligent electricity conservation program. Maybe, but it will take some fancy footwork when combined with the needs for increased electrical power to support robust economic growth.

Then there's the matter of the onerous cost of electric vehicles, but that's another detail the Ultragreen crowd likes to sweep under rug.

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