"You consume more energy gunning it uphill," says Christy Pineda, Tesla’s sales and marketing manager in the northeastern U.S., while noting that the Environmental Protection Agency estimates a Tesla driven normally has a 393 kilometer range. "You can drive more efficiently or less efficiently. It’s up to you."
Such efficiency is a key selling point for electric cars with lithium ion batteries like the Tesla—one buyer in Tesla’s New York City showroom was there to upgrade from a Prius. But electric cars face an extremely difficult simple physics problem: a lithium-ion battery can hold 0.72 megajoules per kilogram, which is why the Roadster packs nearly 7,000 lithium ion cells into its battery pack. A kilogram of gasoline holds 35 megajoules. And plenty of expensive oil remains around the globe to feed our internal combustion machines for years to come.
Pair that with the vast distances often traversed by the average American motorist—a tank of gas will take you from St. Louis to Chicago, for example, while a cost-effective battery that’s also small enough and light enough to perform a similar trip does not yet exist—and it becomes more clear why electric cars have been killed, again and again, starting in the late 1800s.
The Roadster also demonstrates another major hurdle facing electric cars—price. At more than $100,000, the Roadster is a car only for those who can otherwise afford a Ferrari or some other high-end sports car. Hence the fact that roughly 1,700 of them are in private hands in 44 states and 30 countries around the world. Tesla is currently developing its Model S, which will join the Nissan LEAF and Chevy Volt as the family friendly electric cars on the road next year. Yet, all of them cost more than $30,000 per car without any incentives.
Strong government support helps somewhat, including as much as $7,500 tax rebate from the purchase price per electric car and a commitment by President Obama’s administration to put 1 million electric vehicles on the road by 2015. Stimulus money has already paid for the installation of more than 1,800 public charging stations nationwide. Of course, one doesn’t necessarily need a dedicated charging facility; a simple 110-volt outlet in a garage will do the trick for a Roadster, for example.
You can "fill up" a battery for $8 to $10 at current electricity prices in New York—compared to more than $40 for 10 gallons of gasoline—though it won’t take you nearly as far. Such immediate fuel cost savings are one of the primary reasons would-be electric car buyers are interested, balanced against the importance of driving range and speedy charging times, according to a recent University of Delaware survey. The same survey noted that it all comes back to cheaper, stronger batteries—without which electric cars will join hydrogen fuel cells in the litany of government favorites that floundered.
The Chevy Volt—and cars like it—offers a different alternative. The Volt employs gasoline combustion to generate electricity to recharge its battery during driving—turning fossil-fuel burning into a battery range extender. And that means the Volt is secretly a hybrid, like the Toyota Prius, albeit of a different flavor. The Prius, and hybrids like it, switches between its electric and internal combustion engines depending on driving circumstances.
All the hybrids deliver fuel efficiency, but so too do more efficient internal combustion engines. The Obama administration has mandated that cars and trucks get more than 35 miles per gallon by 2016, up from an average of just 25 mpg today. And if the goal is to reduce dependence on oil and reduce greenhouse gas emissions and other pollution, then simply improving the efficiency of internal combustion engines still offers plenty of room to grow, along with hybridizing efforts.
There is a symbiotic relationship between electric cars and those that burn fossil fuels. The original electric cars were already hiding in the average gas guzzler in the form of its battery and electric starter. Reversing that relationship—so burning the fossil fuel helps recharge the battery to drive the efficient and powerful electric motor—might prove the ultimate triumph in this field if the Volt proves successful.
Regardless, both electric vehicles and fossil fuel-burning cars are becoming more and more computer-driven (in some cases, literally). Tesla’s power electronics module, which keeps its Panasonic battery cells at the perfect temperature of 23 degrees Celsius no matter the external conditions with the help of liquid coolant, can easily be adapted to maintaining the health of other auto systems. Or the lessons learned from Tesla’s use of carbon fiber rather than steel or aluminum for its body can be applied to both making that advanced material cheaper and applying it to making other cars stronger and lighter.
In the meantime, in a place such as New York City, chock full of stop-and-go driving, one can return an electric green Tesla Roadster to the garage with nearly the same amount of range left as when one set out thanks to regenerative braking—capturing some of the energy used to slow the car—and that’s an advance that works well for hybrids too. It’s electric, it’s green and it’s here to stay, in one form or another.
David Biello, www.scientificamerican.com/