Thursday, April 05, 2012

What is more expensive – the gas to drive a mile in a Hummer or the wear and tear on a Tesla Roadster battery?

When I bought my Roadster, reports said that driving a roadster costs just a few cents for the electricity. What about the rest of the costs? If you look at just the battery, the current price of a new Roadster battery is $40,000 plus installation costs! The estimated battery life is about 100,000 miles (less if you drive less than about 12k miles per year since the battery degrades without driving). That’s 40 cents PER MILE in the BEST CASE, or, for $4.00 gas, the equivalent of 10 miles per gallon! And that’s just for the battery wear-and-tear.

To be clear, this is the equivalent of the gas tank, NOT the gas. For an electric car, the actual fuel is both the electricity and the battery wear and tear, and just the battery part costs 40 cents per mile. A Hummer gets about 12 mpg highway and 10 mpg city, so at $4.00 gas, costs a bit under 34 cents per gallon highway and 40 cents per mile city.

I love my Roadster as it occupies a unique point in the price/performance/reliability envelope for a sports car. That said, unless the battery aspects of electric vehicles undergo a major overhaul, the economics of the battery alone will make the technology impractical, particularly for more mass market cars such as the Model S or X. 

Perhaps the EPA will start measuring “MPG” on electric cars to include the wear and tear on the battery so it's easier to see what is going on.

As it turns out, the Hummer is nearly 20% cheaper to drive on the highway than the Roadster for just the gas when compared to the wear and tear on the Roadster battery.

That said, I love my Roadster and I'm a huge fan of Tesla, but worried about the economics required for even a moderate main-stream success.