“Want to end dependence on gasoline, forever? We’ll need to replace most cars and light trucks with electric vehicles (EVs). It’s doable, but not with today’s electric power grid.
Here’s the math: The United States burns 138 billion gallons of gasoline annually. The existing fleet of cars and light trucks averages about 25 miles per U.S. gallon, which translates to 3.5 trillion miles of driving.
With today’s technology, small electric cars and delivery vans get about 3.5 miles per kilowatt-hour. To do 3.5 trillion miles, we’d need to use about 1,000 terawatt-hours of electric energy (a terawatt is a trillion watts). Today’s U.S. power grid sells about 4,200 terawatt-hours annually, so to meet the need we’d have to boost electricity production by about 25 percent.
However, driving an electric car 50 miles costs less than 15 kilowatt-hours, and that can be generated daily with a 2.6-kilowatt (kW) photovoltaic array costing, at today’s prices and incentives, about $9,000. (That’s 2.6 kW times $5 per watt, less the 30 percent federal tax credit. It costs less in competitive markets and states with good local incentives.) Think of getting a lifetime supply of gasoline for $9,000. With 15 kilowatt-hours a day, you could drive a car 19,000 miles a year. The system will pay for itself in three or four years in saved gasoline. After that, you drive the car, and every subsequent EV you may own, for the cost of insurance, tires and wiper fluid.
Americans own more than 250 million passenger vehicles, an appalling number for a population of 300 million. We have about 100 million households. Assuming two cars per household, a gasoline-free future is possible, providing each household has access to the equivalent of 5 kW of solar or wind power, either on site or located remotely. Double that distributed power source, and most household electric needs are covered, too.
Under this scheme, does it make sense to package solar modules with new electric vehicle sales? You bet it does.
–Seth Masia, Solar Today, Sept/Oct 2010, page 18