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Plug 'n play: Could plug-in hybrid cars help the energy crisis?

POSTED 29 NOVEMBER 2007


Plug me in! Futuristic hybrid car offers radical energy savings
Between the near-record price of crude oil and the warnings about the end of the petroleum age, it's a great time to be hawking hybrid cars.

Hybrid cars get their power from a regular gasoline engine and a battery-powered electric motor. By balancing the load on the engine and recovering energy otherwise lost in braking, hybrids can get sky-high mileage. Toyota's Prius, for example, gets 48 miles per gallon in the city, and 45 mpg on the highway, much better than the similar-sized Corolla (28/37 mpg).

Man bent over bumper of car, drilling large hole below left rear lightFrom the standpoint of energy conservation or global warming, we do hope that cars with an electric boost may edge out three-ton, four-door, eight-cylinder pickups with gas mileage in the low teens....

Today, if you want to make a plug-in hybrid, you'll need to apply a beefy drill to a conventional hybrid. After this garage surgery, the big, new battery in this Prius can be charged from a standard wall outlet. Photo: Wisconsin Public Power, Inc.

Hybrids combine the reduced air pollution and higher efficiency of battery power with the longer range of a gasoline engine, producing a car that travels further on each unit of energy while reducing the use of fuel and the release of carbon dioxide, the primary greenhouse gas.

More than half a million hybrids are selling annually in the United States, and manufacturers are scrambling to join the hybrid herd. Whether their motivation is a desire to brag about high mileage or to bask in the glow of "hybrid chic," hybrids offer a quick route to reducing gasoline consumption, oil imports, and greenhouse-gas pollution.

The best is yet to come
But it turns out that today's hybrids are only a start: The next generation of "plug-in hybrids" promises much greater reductions in fuel consumption and pollution. These cars use a super-size battery to achieve much greater all-electric driving range.

While today's hybrids resemble conventional cars with a battery assist, the plug-in version is more like a battery car with gasoline assist. Like the battery car, the plug-in hybrid offers radical pollution reductions, but adds the critical advantage of unlimited range.

When the battery is charged from a regular electric outlet at night, it stores enough energy to drive 20, 30, even 40 miles. Even though batteries are heavy and expensive, a 30-mile battery could liberate most American commuters from gasoline, especially if the car is charged at work before the drive home.

Plug-in hybrids could make visits to the gas station a special occasion rather than a weekly misery.

At today's prices, energy will cost about one-third as much when electricity rather than gasoline is moving the car, so plug-in hybrids could reduce the cost of driving.

But the ultimate payoff of plug-in hybrids is this: By placing a big battery in millions of garages, they may open the door to a vast expansion in solar and wind electricity.

Graph with three columns, a car at the top of each column, demonstrates the benefits of driving a plug-in hybrid.
A plug-in hybrid can save more than the green on our Earth-it can save green in your wallet, too. A Google project called RechargeIT calculates the savings this way: The average American car gets 19.8 miles per gallon and drives about 12,000 miles per year. At $3 a gallon for gasoline, that adds up to $1,818 per year on fuel. If, as RechargeIT found, a plug-in hybrid gets 73.6 mpg, the total cost for electricity plus gas comes to $616 per year, a saving of $1,202. (This calculation does not account for the cost of the conversion kit -- roughly $10,000. Prices should fall with increasing volume.). Details on the calculations: Google

Plug in, turn on, drive off
No manufacturer yet makes a plug-in hybrid, although several firms do sell kits with a big battery and control unit that will convert an existing hybrid into a plug-in. A number of auto-bigs, including Toyota and GM, say they intend to release plug-in hybrids within a few years.

That announcement marks a fascinating about-face for Toyota, which has long emphasized that its Prius was not a battery car. "They worked a long time to explain that you don't have to plug these in," says Don Hillebrand, director of the Center for Transportation Research at Argonne National Laboratory. "I think that one thing that spooked Toyota [about introducing a plug-in hybrid], is that they had just got done with explaining that the Prius does not have a cord coming out of the tail."

Two cars, one silver and one dark red, have extension cords trailing from their bumpers.
A pair of plug-in hybrid electric cars get set for testing. Doesn't your car have a tail? Original graphic from: Argonne National Laboratory

The Why Files could not afford a plug-in hybrid, so we phoned Tom Paque, a vice-president of Wisconsin Public Power Inc., which converted two Priuses as corporate cars. "We get a lot of thumbs up," Paque told us. "I think in general people don't know much about plug-in hybrids, but I do believe they understand [the idea of] using electricity in cars, and are excited about it."

Aside from all the technical hurdles involved in producing long-lasting, powerful but affordable batteries, Paque says, "It's going to be a challenge, from the consumer perspective, to explain these. People have the assumption that battery-powered cars are slow, and have limited mileage.... This approach, adding an 'electric gas tank' to a hybrid, is a really cool incremental step."

How do plug-ins work , and can they help?

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Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive

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