|Aug 06, 2010
||Posted By: Mark Bilek
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From the Chevrolet Volt to the Nissan Leaf to the Mitsubishi MiEV, there's been a lot of talk about electric vehicles in the news lately. The reporting ranges from insightful to ridiculous and everything in between. So, I thought I'd take time out to set the story straight on electric vehicles.
First off, mainstream electrics aren't coming to Chicagoland anytime soon. Though the Chevrolet Volt launches this fall, it's not coming to this market for at least another year. Ditto the Nissan Leaf, which will initially be sold only in Washington, Oregon, California, Arizona and Tennessee.
The reason for this is quite simple; batteries and Chicago's climate don't play nice. Most batteries like to be cool, but not cold. Extreme cold and extreme heat greatly reduce the capacity of a battery, and we have lots of cold and heat here in the Windy City. So an electric vehicle that has an ideal range of 100 miles in 60 degree weather might see practical range drop by 50% when the temperature dips below freezing.
Eventually, the electrics will come. The reason is simple--efficiency. Even the most fuel frugal gasoline or diesel engine is only about 30% efficient. In other words, a piston engine transforms 30% of the energy in the fuel into forward motion. The other 70% is lost to heat and friction.
When properly sized, electric motors are substantially more efficient--in some cases twice or three times as efficient as a comparable piston engine.
The drawback to producing an electric car has always been battery capacity. Quite frankly, until battery capacity and temperature compatibility are greatly improved, pure electric vehicles aren't likely to gain much traction in the marketplace. That's why Chevrolet hedged its bets with the Volt. Both the Leaf and Volt use electric motors and battery power to turn the wheels. The Leaf works like a golf cart. Owners charge the batteries and drive until the charge runs out.
Unlike the Nissan Leaf, the Volt adds a range-extending gasoline engine to the equation. When the battery charge is depleated, the gasoline engine turns a generator to create electricity to keep the batteries charged and the electric motor powering the wheels.
You might not think that's not very efficient, but it is. The reason is quite simple. The gasoline engine is tuned to run only at its most efficient speed, regardless of how much electricity is needed by the electric drive motor. The engine simply kicks on and charges the batteries at a constant state and then the batteries store that energy until needed.
Both the Volt and Leaf can be plugged in to recharge the batteries. Nissan says the Leaf can drive up to 100 miles on a single charge. In the case of the Volt, Chevy claims optimum range on purely electric power is 40 miles. The difference is between the two is that in the Leaf you have to stop and charge the batteries when the charge runs out, while in the Volt the gasoline engine kicks in and allows you to drive another 300 miles or so.
Nissan Leaf Web site
Chevrolet Volt Web site