Chevy volt mileage takes people for a ride

Flying carpets – also known as magic carpets – have appeared in literature since nearly biblical times. It’s human nature to wish for a mechanism that can transport oneself almost magically without the use of any energy except that of the imagination.

The Chevy Volt is the latest example of wishing for a mechanism to transport oneself nearly magically. At the advertised 230 mpg, it certainly must be magic. Because, like a flying carpet, it defies the laws of physics.

After reading several articles about the Volt, I really was dismayed about the almost intentional lack of specifications. Something as simple as the weight of the vehicle would have been really useful, and I still don’t know what it is. (Reporters are typically not energy geeks).

When I look deeper, after visiting the Chevrolet Web site, I learned even less. But overall, I extracted the following:

This vehicle is an electric car with an onboard gasoline generator that charges batteries to increase driving range beyond the 40-mile, fully charged battery range. It is similar to the diesel electric locomotive, which for all intents and purposes is a giant rolling generator burning diesel oil to make electricity to energize the electric motors that propel the locomotive. How does the Environmental Protection Agency calculate the miles per gallon of an electric vehicle? It’s not very clear; in fact I don’t even think that they know yet.

But using some simple algebraic equations and the limited information gleaned from several articles, and the Chevy Web site, we get this: 8 kWh overnight charge moves the vehicle 40 miles, (Chevy’s Web site claims the electrical efficiency of the electric drive motor as 25 kWh per 100 miles).

The onboard generator produces electric at about 50 miles per gallon of gasoline. How does General Motors arrive at the 230 mpg?

Apparently, the Chevy Volt will actually achieve the stated 230 MPG if the car is driven on fully charged batteries for 40 miles and then using the gasoline powered electric generator for 11.1 miles. A total of 51.1 miles consuming a mere .22 gallons.

We can check our math by a simple fuel consumption calculation, like in the old days when we just drove gasoline-powered cars: .22 gallons of gasoline per 51.1 miles driven equals 232 miles per gallon.

The GM advertising numbers are deceptive and only serve as a marketing tool.

If we lived in a world of higher integrity, GM and the EPA could rate the energy consumption something like this: 5 miles per kWh in electric mode, and 50 mpg in gasoline mode, which is kind of straight forward and honest – but it’s not sensational.

For those readers who are thinking, “Well, at least it’s a clean car,” Where does the electric come from? Fifty percent of the electrical energy produced in our country is from a coal power plants. If we start to drive electric cars, then expect to start building many more power plants. Later, we can explore all the inherent electric grid inefficiencies.

Knowing that, don’t you just wish we could go for that carpet ride?

Rob Hothan is a property manager, certified Energy Star contractor and developer who lives part-time in Rocky Mount. He has made many mistakes and therefore has much to share. He has a master’s degree in Energy Management and an advanced certificate in environmental technology.