Electric Vehicles: Pros and ConsQuiet, smooth, emissions free-but expensive, limited range, slow to charge
In the early days of automotive history, electric cars were more popular than the other alternatives, gasoline and steam-powered vehicles. Gasoline was volatile, highly flammable, scary to store and tote around in a tank. (Ever wonder why early garages were on the other side of the lots from car-owners' homes?) Scalding-hot steam was nearly as frightening, and not much fun to use, or fast to make.
Transfer of Power
Electric volts, by contrast, were easy to store and use and cheap to replace. EVs didn't go very far or fast, but who needed to at the time? Just turn the switch and step on the pedal. Folks didn't hear or smell you coming or going. Once there, switch it off and plug it in.
While the nearly 4,200 motorcars built in 1900 were roughly one third each electric, steam and gasoline, enthusiasm for steam cars soon waned, while gas and electric cars grew. The former offered higher speeds, longer range and much quicker refueling; mostly women enjoyed the latter for local use. But electrics faded fast after electric starters eliminated engine cranking, enabling anyone to operate a gas-powered car, and internal combustion engines (ICEs) have dominated ever since.
Now, growing concern for national security and the environment and unpredictable, sometimes sky-high, fuel prices have revived strong interest in volt-powered vehicles.
There's no question that EVs enjoy a number of important advantages over fuel-powered cars. For starters, electric motors emit nothing and don't care where their volts are generated. In the future, they can come increasingly from squeaky-clean sources such as solar, wind and hydro. And they produce just 5-10 percent of an ICE's potentially harmful emissions per mile traveled even when the electricity source is an oil- or coal-fired plant.
They are also quiet, mechanically simple and three times as energy efficient-in terms of the amount of stored energy that gets to the wheels-vs. gasoline ICEs, and an electric motor needs no transmission because it generates maximum torque from zero rpm. Another key advantage is regenerative braking, which turns the propulsion motor into a recharging generator during coasting and braking. "Regen" can recapture 20-25 percent of the energy that conventional brakes waste as heat, and the car's lightly used friction brakes last much longer.
On the other hand, there are many good reasons why gasoline engines blew boilers and batteries out of business in the industry's early years. Batteries were bulky, heavy and expensive, they could store only a fraction of the energy of a much smaller, lighter and cheaper tank of gas, they took hours to recharge, and they needed frequent replacement.
EV interest revived briefly in the 1960s and early `70s amid growing ICE emissions and (following the `70s fuel shortages) gasoline cost and availability concerns. General Motors, among others, built some concept EVs and the first fuel-cell EV, and a few companies sold very small numbers of battery electrics. But as petro-fuel worries waned, those efforts faded.
In January 1990, GM ignited EV passion again with its bullet-shaped, ultra-efficient Impact electric concept car, co-developed with California high-tech firm Aerovironment, which flaunted impressive performance and range numbers. So enthusiastic were the press and public responses to it, in fact, the company decided to explore volume production. That April, it established a small, elite engineering group to do exactly that.
California then tried to force an EV market by mandating the top seven automakers to make two percent of their sales in that state "zero emissions" by 1998, with the requirement ramping up to 10 percent by 2003. That forced GM and its six strongest competitors into simultaneous EV development and competition, whether or not the technology would be ready.
Intending to lead EV technology and sell it to other automakers as well as consumers, GM invested over a billion dollars to bring its Impact-like EV1 to market for 1997. Except for a few hundred aficionados, however, consumers shunned it as an expensive two-seater with very limited range. Toyota, Honda and Ford also tested the market with small numbers of conversion EVs. But when no battery materialized that enabled EV range to compete with a tank of gas, the ill-considered California sales mandate was delayed then finally abandoned.
While the advantages of EVs over ICEs are indeed impressive, a fair assessment of their disadvantages-virtually all relating to on-board energy storage-reveals that the challenge for volume sales remains daunting. The latest lithium ion chemistry can hold roughly twice the energy per size and weight as today's commonly used nickel metal hydride (NiMH), and nearly four times that of lead-acid (PbA), but a pack large enough to power a decently efficient and practical EV for 100 miles on a charge will remain large, heavy and expensive. Figure 800-1,000 lb. for 30-40 kWh, roughly double the Chevy Volt's 400-lb. 16-kWh pack. And that 100 miles-about a third the range of a typical tank of gas-will be difficult to achieve in cold and/or wet weather due to reduced vehicle efficiency, in hilly areas and in less-efficient conversions of conventional cars and trucks. EV drivers will have to carefully plan their days around their vehicles' range and know where they can catch a partial charge at a public station while lunching or shopping. And always keep in mind that if they don't make it to a plug, they're stuck. They won't be able to go fetch a can of volts and carry it back.
A full charge of a pack that size will take 12-16 hours on 110/120-volt house current and-though a lucky few may have charge stations at work-will best be done at home overnight on a 220/240-volt charger, which will take 5-6 hours. Then there's the question of battery life and replacement cost, though that should be covered by new-car warranties for 8-10 years.
For these reasons, pure battery EVs will likely remain low-volume niche vehicles for the committed few until a safe, reliable and affordable battery (or other) system is developed that can compete with a tank of gas in driving range and charge time. Until then, gas/electric parallel and range-extender hybrids will continue to offer the best marriage of EV and ICE advantages.
About the Author
Former automotive engineer Gary Witzenburg has been writing about the auto industry, its people and its products for major magazines, newspapers and web sites for more than 20 years.
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