You Can't Drive the Volt from LA to Houston?
By Bill Moore
General Motors not only has a serious financial challenge, it has an educational one as well. Consider the following statement of one Steven Laib on the Intellectual Conservative web site.
"Electric powered vehicles have been a goal ever since the dawn of the automobile. The trouble is that so far they do not live up to the American standard of being able to take you anywhere you want, any time you want with a five-minute recharge after a 300 or 400-mile trip segment. Driving from Houston to California in a Chevy Volt would be impossible."
Mr. Laib isn't the only person laboring under the assumption that the plug-in hybrid or 'extended range electric vehicle' (EREV) -- I personally prefer REEV -- is limited to the driving range of its battery pack. Presumably, he thinks the gasoline engine on the vehicle is there to recharge the battery AFTER it runs out of energy. He seems to be laboring under the assumption that you'd have to sit there running the engine-generator for hours until the battery was sufficiently recharged to drive another 40 miles. Yes, at that rate, you'd never get to Houston.
So, for all the Steven Laib's of the world, here's how the Volt works.
You wake up each morning to a fully charged battery that holds 16 kilowatt hours (kWh) of electrical energy. Just so you understand what a kilowatt hour is, think of a 1000 watt electric hair dryer running for one hour or ten 100 watt light bulbs burning for 60 minutes. That's one kilowatt hour worth of energy.
If you used all 16 kWh of electricity stored in the Volt's battery pack you could drive somewhere around 80 miles as an electric car. General Motors, however, only wants you to use half the energy in that battery or 8 kWh. By doing so, they can help extend the life of the battery to meet it's expected 10 year or a 150,000 miles life.
So, when you unplug the car each morning, you have up to 40 miles of electric-first driving range at freeway speeds and in all climates. If you live less than 40 miles from your workplace, your four cylinder 1.4 l gasoline-fired engine never turns on; you don't burn a drop of fuel.
But let's say your commute is 28 miles one way or a total of 56 miles round trip. You can't recharge the car at work since your employer hasn't yet installed a place to plug-in the car. Your total trip is 16 miles beyond the range of the battery. What do you do, or more accurately, what does the car do?
You don't run the engine-generator while the car is parked at work. Using gasoline to recharge the battery is inefficient,environmentally irrresponsible and expensive compared to power from the grid, so Volt engineers designed the car to return home with the battery pack depleted.
Around mile 40 on the drive home from work, the EcoTec engine starts automatically and begins to spin its integrated electrical generator -- while you're still driving. You may notice a slight increase in cabin noise and vehicle vibration. You'll also see on your instrument panel a gauge that shows you're now in charge sustaining mode consuming around 50 mpg of gasoline. You haven't had to stop and let the batteries recharge.
The car keeps right on rolling with the engine-generator producing just enough electrical power to continue to propel the vehicle down the road, while also putting any additional charge from the generator or regenerative braking back into the battery pack.
Because the Volt is, technically speaking, a series or serial hybrid, the gasoline engine is not directly connected to the drive train. It only spins the electrical generator, which is sized large enough to provide sufficient current to the car's electric traction motor to keep the Volt moving down the road at highway speeds.
You complete the last 16 miles of your commute burning one-third of a gallon of gasoline, or just over a liter. For the five day work week, you'll use a total of 1.6 gallons of fuel to drive a total of 290 miles, effectively giving you the equivalent of 181 miles per gallon fuel economy. Of course, you will also be consuming 40 kWh of electric power at a national average rate of 10 cents per kilowatt hour or $4. Your total work day commute costs you under $10 ($4 for electricity -- at peak rates, its likely to be less at night-time rates -- and $4.80 of gasoline -- assuming gas does to $3 a gallon again.)
But on the weekend, you're planning to drive from Houston, where Mr Laib lives the comfortable life of a semi-retired attorney to Malibu, California, a distance of 1,500 miles. You'll head west on Interstate 10 towards San Antonio. Somewhere between Brookshire and Sealy, you'll notice your charge-sustaining gauge turns on, indicating that the Volt's engine-generator is now powering the car.
You continue motoring along I-10, looping around the top of San Antonio and head north-by-northwest towards the Texas hill country and its vast stretches of scrub oak forest. At Kerrville, you've travelled some 260 miles and your fuel gauge shows you have a quarter of a tank remaining. It's time to refuel so you pull off the Interstate and put in a few gallons of gasoline. A quick calculation shows you're getting nearly 50 miles per gallon. And so your trip to California continues, stopping every 300 or so miles to refuel while still getting surprisingly good fuel economy.
After a long, hard day, you spend the night in Las Cruces, New Mexico at a Holiday Inn Express that has just installed charging points to attract upscale clients like Mr. Laib. They tack on a modest $2 charging fee -- the electricity cost them $0.80 -- to your bill. Much of the power comes from a nearby gas-fired power plant operated by El Paso Electric, the cleanest and most efficient of the fossil fuels. The next morning, the battery is full and with a cup of coffee and a bagel in hand, you resume your trip west.
You spend your second night in Palm Springs, staying at yet another motel with charging services. This time, the power comes from hundreds of wind-turbines that crowd the desert floor west of town.
The next morning, bright and early, you set off on the last leg of your trip to Malibu. The first 40 miles of the remaining 120 are again electric-first, with the remaining 80 using well under two gallons of fuel. The entire 1,500 trip out to California consumed under 30 gallons of fuel and 24 kWh of electric power. The same trip in a Lexus hybrid would consumed twice as much gasoline.
So, Mr. Laib's erroneous assertion to the contrary, the Volt will be able drive from Houston to Los Angeles and back, just like the car parked in his driveway. But it really shines on the day-to-day, urban commute where it does what it does best, run for up to 40 miles on electrons instead of imported oil. But for an attorney who probably made his money working for oil and gas companies, that's a problem, isn't it?
Good thing he's retired.
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