On the Clock with Matt Doude

Bagley College of Engineering experts answer your questions about engineering, technology and life.

Photograph by Megan Bean

High prices at the pump have American drivers opening their minds and wallets to alternative-powered vehicles. But, as new options become available, conflicting reports of their safety and practicality leave many consumers with more questions than answers. Matthew Doude, a research associate at Mississippi State University’s Center for Advanced Vehicular Systems, explains what consumers should understand to get the most vroom for their bucks.

A six-year participant in the General Motors and the Department of Energy series of advanced vehicle design competitions, Doude led a Mississippi State team in the development of a plug-in hybrid SUV that earns 118 mpg and has a 60-mile all electric range. He currently serves as the team’s staff adviser.


Q: What is the difference between hybrid and electric vehicles?

A: A hybrid uses two sources of power for propulsion, such as gasoline and the electricity it generates on board. Advanced systems, like regenerative braking or idle-off, let it use gasoline more efficiently than a standard car. An electric vehicle uses only one power source, electricity. There is an in between category called plug-in hybrids, which can either take gasoline or plug into the wall to receive electricity. These cars operate like an electric car at first and like a hybrid once the electric charge wears down.

Q: Of the different types commercially available, which do you think is most practical?

A: That answer depends on the driver’s situation. For drivers who know they drive a set distance everyday, like 40 or 50 miles, an electric vehicle is probably the best choice because it only uses electricity. But to me, the most practical is the one that gives the most fuel options and that is a plug-in hybrid.

Q: Why do you consider more fuel choices to be more practical?
A: Because it gives the driver flexibility. If you have a standard car, but you can’t get gasoline, you’re stuck. And in an electric, you can only drive as far as the electric charge will take you. With a plug-in hybrid you can drive all-electric for short trips, which is very efficient, or you can use gasoline for longer drives.

Q: How does the performance of these vehicles compare to standard automobiles?

A: These cars are designed to match the performance of most other cars on the road. There is a little bit of a tradeoff in cargo capacity but it’s not as big a difference as most people expect. The biggest tradeoff consumers will see is the price. Plug-in hybrids, for instance, cost $7,500 to $10,000 more than standard vehicles, which is substantial for most people.

Q: Are these vehicles more expensive to maintain than a standard car?

A: If you buy a car with advanced technology, you will be limited to getting it serviced at the dealership because its technicians will be trained for those systems. The cost will probably be a little higher, but all the different hybrid and electric cars have pretty good maintenance warranties.

Q: What about maintaining or replacing the battery?

A: The batteries in hybrid and electric cars are expensive, but they are designed to last the life of the car. They will lose a little bit of their capacity overtime, however hybrids have software that monitors the battery so people don’t have to worry about over-or undercharging it.

Q: Are hybrid and electric car batteries dangerous?

A: If, 100 years ago, the electric car had taken off in popularity instead of the gas-powered car, and today someone designed a car with 15 gallons of gas under the driver’s seat, people would think that was absurdly dangerous. That’s what we are all used to so we don’t think about it. It all depends on what people are accustomed to. Actually, the energy in the battery is more stable than gasoline and the battery itself is safer than a gas tank.

Q: Are there any unique dangers associated with hybrid or electric cars?

A: The cars do have high voltage systems that could be dangerous, but the cars are monitored by onboard safety systems that will shut the power off if there are any problems.

Q: How are plug-in hybrids and electric vehicles charged?

A: Most can be charged from a standard wall outlet, but it will take most of the day. Another option, which will recharge it more quickly, is to use a charging station. You can have one of these stations installed at your home for around $1,500, and in some areas there are grants or initiatives that will help cover the cost.

Q: If people start using electricity to power their cars, won’t that put a strain on the power grid and cause brownouts?

A: That’s a common misconception. Brownouts almost always occur during the day when air conditioners are running on high and businesses have their lights on. But these cars are almost always charged at night when the electric power demand is less, which causes power plants to be less efficient. Ultimately, if there are millions of these vehicles in use, it will make power generation more consistent and efficient.

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ENGINEERING @ MSSTATE
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