Everybody knows; fishermen never lie about their catch. Sometimes they can embellish their stories just a little bit.
The auto industry has found that customers can be lured by high mileage figures. The media has joined the enthusiasm for energy efficient cars. Suddenly we read mileage claims starting at 60 MPG all the way up to mind-boggling claims of 200 MPG to 300 MPG. Miles per gallon, or MPG, is supposed to be a number car buyers can confidently use to estimate future fuel and energy costs before buying a car.
GM recently announced that its new VOLT electric car will get 230 MPG. WOW!! How do we know how much is embellishment and how much is real?
We must first realize that the VOLT is a hybrid! When looking at driving costs, users should realize that they have to pay for energy in the form of electricity or gasoline. For the following comparisons it is assumed that electricity costs are $0.11 per kWh when connected to a receptacle at home and that gasoline costs $2.50 per gallon at the pump.
GM has not yet stated how much gas and how much electricity the car consumes when driving 230 miles. We have to guess. A mileage figure of 230 MPG can only be achieved when the car uses just one gallon to drive 230 miles. GM tells us that the VOLT has a range of forty miles when using just its batteries. Media reports indicate that the VOLT will also have a 1.4 liter gasoline electric generator. Giving GM the benefit of the doubt, we can assume the VOLT will achieve 50 MPG when driving on gas on the highway at 55 miles per hour.
Now we can calculate the mileage that VOLT can optimally achieve. The VOLT must drive 180 miles on its batteries and 50 miles on the highway on gas to reach the advertised mileage. Only in the best of cases is it possible for the VOLT to use just one gallon of gas to drive 230 miles! In addition, the VOLT must be charged at least once at home and four times at roadside charging stations when traveling within 230 miles of home.
GM says costs to drive the VOLT will be $2.75 per 100 miles at an electricity cost of 11 cents per kWh. The comparable cost of gasoline power at 50 MPG would be $5.00 per 100 miles, provided that gasoline is $2.50 at the pump.
Recharging the VOLT’s batteries on the road will cost much more than 11 cents per kWh. (kWh is an abbreviated unit of electrical energy for kilowatt hours). No gas station owner can afford to buy expensive refueling equipment and provide multiple parking spaces for the slow refueling process without a fair surcharge. Let’s hope that the price of electricity at the motorway recharging point does not exceed 17 cents per kWh.
Recharging the VOLT’s batteries with a storage capacity of 16 kWh will cost $2.72 down the road. According to GM, the VOLT can travel 40 miles on a fully charged battery. Therefore, the cost of driving 100 miles will be $6.80. When driving with gasoline, the cost will be $10.00. The difference in driving costs per 100 miles will be $3.20.
After driving 100,000 miles, the VOLT can save $3,200 in energy costs when driving on highways. The VOLT can save much more energy costs when it is only recharged at home. Energy costs when driving exclusively on home-delivered electricity will be $4.40 per 100 miles when using a 16 kWh battery and getting 40 miles per charge.
The estimated driving cost of $4.40 per 100 miles is considerably higher than the $2.75 per 100 miles quoted by GM. It seems that GM needs to explain the VOLT’s performance more precisely.
More importantly, the advertised mileage of 230 MPG is a fairy tale and requires a very long, exhaustive and complex explanation. It’s a trick to sell hybrids. Consumers should insist on more understandable information to forecast driving costs. The 230 MPG figure is misleading!