"A gallon of gas weighs about 6.3 pounds and produces roughly 35 kilowatt hours of energy. That’s enough to burn a 100-watt light bulb continuously for more than two weeks. A lead-acid battery could do the same thing without needing a recharge—if it were the size of a desk and weighed a ton. Energy density is the point. We just haven’t come up with a fuel or a device that will safely and economically offer the same calorific value in such a small space as an automobile’s gasoline tank. Compressed natural gas (CNG) and liquefied natural gas (LNG) intrigue us, but the problems of storing them (or hydrogen) in a car in sufficient quantity to approach gasoline’s range and performance continues to be a sticking point. We always come back to density.
Oddly, nothing better illustrates the overall efficacy of gasoline than an electric car. In 1900, when electric, gasoline, and steam cars were vying with one another, an article in American Monthly Review of Reviews pointed out that the gas car had “developed more all-round good qualities than any other carriage,” not the least of which was that “it carries gasoline enough for a 70-mile journey and nearly any country store can replenish the supply.” It was true back then and it remains true today. The standard to which electric cars aspire—for speed, flexibility of operation, and range—is the gasoline standard.
We may earnestly speculate about flywheels and compressed air and various gases, natural and unnatural—but we go with gasoline.
Right now the impressive Tesla electric roadster is the darling of the automotive press. Its beguiling style and cutting-edge technology have made it a sensation, albeit an expensive one, at close to $100,000 a copy. Instead of conventional lead-acid batteries, or nickel metal-hydride (NiMh) batteries such as those that are used in the Toyota Prius hybrid, the Tesla draws its energy from an elaborate and sophisticated array of 6,831 interconnected lithium-ion batteries—the kind used to power top-line laptops. These batteries, each a little bigger than a common AA alkaline, are immersed in a liquid cooling system to prevent them from becoming too hot and possibly bursting into flames when under the stress of feeding a total of 375 volts to the Tesla’s electric induction motor.
Enthusiasts see the Tesla as the “I told you so” electric car, with its world-class acceleration (a reputed 0 to 60 mph in 4 seconds), a top speed of over 120 mph, and a claimed range of 220 miles. But that range will bear some scrutiny in real-life conditions as Teslas start getting into the hands of owners. Automotive testers are already sounding some warning bells. John O’Dell, who test-drove the car for Edmunds Inside Line, notes that its range may be “more like 180 miles if you like to goose it every once in a while and down around 150 if you regard speed limits as mere suggestions.” In other words, if you drive it like a sports car (which it is) you will experience a steady deterioration of performance as you drive. Add the weight of a passenger or the challenge of a curving road through hills and the downturn is more pronounced. O’Dell observes: “The quickest your electric sports car will be is in the first few minutes after you leave the garage. It just gets slower after that until you return home again.”
Make no mistake—the Tesla is an impressive performer, praised for its handling, its responsiveness in tight spots, and its rocket-like acceleration. It is often compared to a Porsche 911. Okay. Let the Porsche drag with the Tesla a few times. The Tesla may well reach 60 mph slightly faster than some versions of the 911. But, while the Tesla’s batteries are electronically panting and cooling off and its dash displays are flashing warnings about decreased range and automatically restricting the electric motor’s torque, the Porsche will go merrily on its way and cruise up to 400 miles on the remaining gasoline in its 17.7 gallon tank.
And while the Tesla is recharging its batteries over a period of hours, the Porsche can have its tank refilled in a minute or two and be on its way. The electrically refreshed batteries in the Tesla will then begin another cycle of diminishing performance, while the gasoline in the Porsche’s tank will give it optimum performance to the last drop. For all its technological edginess, the Tesla is really just another example of why gasoline is still king. After all the promises of their yesterdays, electrics remain the cars of tomorrow because no battery or combination of batteries has duplicated the energy density of a gallon of gasoline."
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