Electric Chevy Spark dash

To mark yesterday's unveiling of the electric 2013 Chevrolet Spark, GM released a new graphic showing the dashboard and an outline of the car. The computer-generated image of the Spark's dash displays the electric city car achieving a shocking 18 miles per kilowatt-hour. That's mighty impressive considering that most plug-ins return around four miles per kWh.

While we didn't immediately notice this 18 mi/kWh readout, electric vehicle enthusiast Neil Riley did. Riley quickly posted this comment over on Green Car Reports:
If the battery is really a 20-kilowatt-hour capacity pack and the car gets 18 miles per kWh as depicted in the dashboard picture, the range computes to 360 miles per charge. Now that would be really great. Am I wrong in my findings?
GCR immediately shot an email to General Motors, asking whether or not the electric Spark was truly capable of returning such remarkable numbers. GM spokesman Rob Peterson replied:

While everyone else was asleep, we have managed to disprove the First Law of Thermodynamics, allowing us to move from approximately four [miles per] kWh to 18. The perpetual motion machine is squarely in our sites, and in our product portfolio.

It's nice to see this sense of humor, but the truth isn't as fun. Peterson continued:
The actual answer is, no. Our graphic is incorrect.
Maybe someday 18 miles per kWh for a passenger car will be nothing noteworthy, but today it remains pure fantasy.