An article in the January/February 2011 issue of the Massachusetts Institute of Technologys Technology Review explains that the three best hopes for carbon dioxide emission-free cars are electricity, hydrogen and biofuels from nonfood sources. All three face serious technological challenges, but the automotive industry appears to have picked electricity as its winner. There are at least 10 car companies with some form of electric model in the works, and several are scheduled to be ready this fall.
Electric, apparently, is also the pick of the Obama administration. In his 2011 State of the Union message, the president said, The goal is to have everyone driving electric cars by 2030. To skew the market toward that goal, the government offers a $7,500 tax incentive to buy the cars.
At the recent North American International Auto Show, the electric models were described as a propulsion revolution. But as another article in the same issue of Technology Review points out, the revolution is dependent on batteries that still have small storage capacity, short lives and high costs.
The new models are either all electric or a combination of electric and a gas engine. Three examples of different approaches are: the all-electric Nissan Leaf; the GM Volt with a battery and gas engine combination; and a different gas-battery combination from Toyota. The Leaf and the Volt will be available this fall. The new plug-in Toyota Prius will be introduced in 2012.
All the new models use lithium-ion batteries. The largest are in the Nissan Leaf that advertises a range of 73 miles, but weather and other slow driving conditions can lower that range to 40 or 50 miles. Electric-only cars all have similar variability in the distance they can travel, which some believe will lead to range anxiety. Charging time varies from 30 minutes at a 480-volt quick-charge station, to seven hours at 220 volts. The battery pack on the Leaf is projected to cost $18,000. The sales price of the car, around $33,000.
The GM Volt batteries are smaller, with an advertised travel range of 35 miles. To compensate for the short range, the Volt has a gasoline engine that generates electricity so that it can continue to recharge the batteries and power the car after 35 miles. Combining the battery pack with a gas engine and transmission, however, is expensive, and the Volt is expected to sell for around $41,000.
Toyota has made a different set of trade-offs. Its batteries are much smaller, limiting its electric-only range to 13 or 14 miles. Also its electric motor is not designed for traveling faster than 60 mph without help from the gas engine, whereas the Volt can hit 100 mph. The positive side is that the plug-in Prius is expected to have improved fuel efficiency over the present Prius, and is projected to cost less than either the Volt or the Leaf.
The market will tell which of these ways to use batteries, if any, makes the most sense. For the U.S. and Canada markets, some experts give the advantage to the Toyota design. They believe miles per gallon will be more important than being able to go short distances gas-free because the average distance traveled is greater in North America than the gas-free range for many of the cars. If the Leaf and the other all-electric designs are to sell well, it should be in the European and Asian markets where driving distances are shorter.
Batteries are clearly the nemesis of electric cars. While new battery methods are being developed in laboratories around the world, as yet there are no proven breakthroughs in the range-to-size ratio. Furthermore, according to the Technology Review article, even when a successful innovation is found, it will take a decade or more before it can be installed in production cars.
Despite battery limitations, some potential buyers want to own an electric car simply because they believe it will help reduce carbon dioxide emissions. But even if the current models are sold in reasonable numbers, they will have little effect on overall emissions in this country. Thats because electricity production itself contributes 35 percent of current U.S. output, and as yet no national effort has been implemented to produce base load electricity from carbon dioxide-free energy that electric car owners can use.
Even with the $7,500 bribe, probably the best benefit/cost trade-off for potential car buyers, given the high electric car costs, battery replacement costs and the limited environmental improvements the cars offer, is to purchase one of the new small and cheaper vehicles with high gas mileage between 35 and 40 mpg that were in this years auto show. As Joseph White predicts in his story, headlined Detroits Woes Make for Better, Smaller Cars (Wall Street Journal, Jan. 19) ,If you go shopping for a small or mid-sized fuel-efficient car this fall, youre probably going to like what you see.
Garth Buchanan holds a doctorate in applied science and has 35 years of experience in operations research. Reach him at firstname.lastname@example.org.