One of the reasons I was very impressed with the Model S is Tesla’s progress on efficiency in just four years. The following table compares the Roadster to the Model S and the Nissan Leaf in terms of MPGe, kwH / 100 Miles, and Miles / kwH.
The federal government calculates a MPGe number which is a way to compare an electric car to a gas powered car. Their electric “mpg” is kwH / 100 miles, which has an inverse relationship to MPG. A more efficient car has a lower kwH / 100 mile rating. A few years ago I wrote a post suggesting Miles / kwH would make more sense as it correlates more to MPG.
Looking through this table you can see how impressive both the Tesla cars are. The Roadster has the highest rating. The Roadster uses significantly less electricity than the Nissan Leaf and the Coda, has a longer range and is a lot more fun to drive.
The Model S is also very impressive. It is a significantly larger and more luxurious car and weighs a lot more but uses close to the same amount of energy per mile than the Nissan Leaf with a much larger range.
I was honestly quite surprised by these numbers. I asked the folks at the Tesla showroom how they managed to achieve such efficiencies in the last few years. Their answer was a lot of aerodynamic improvements but also a lot of development work in the motor and other parts of the car – which are no longer “under the hood”.