Tesla Motors recently launched its long-awaited electric roadster, offering drivers a tantalising combination of planet-loving fuel parsimony and supercar-style power.

The car accelerates from 0 to 60 miles per hour in 3.9 seconds, but gets the equivalent of 135 miles per gallon, making it zippier than a Porsche 911 Carrera, but more than twice as efficient as a Toyota Prius hybrid.