Wednesday, January 17, 2007

The Electric Car Arrives—Again?

In 1990, General Motors Chairman Roger Smith announced that his firm was developing an all-electric car for the consumer market, partly in response to a California law mandating the sale of zero-emission vehicles in the future. Six years later, the EV1 made its debut in California and Arizona. Only about a thousand were made, and technically you could never own one—GM allowed only leases. In 2002, concluding that the program failed, GM demanded the return of the vehicles, much to the dismay of some loyal EV1 drivers who saw the move as a back-door way to show that electric vehicles were still impractical. Just last week, GM announced at the Detroit International Auto Show that it plans to get back into the electric-car business with the Chevrolet Volt, a home-chargeable battery-operated model that carries a small gasoline engine. Should we believe them this time?

In fairness to GM, whose well-known financial woes have more to do with pensions and a glut in the world auto market than missing advances in technology, selling electric cars to everybody will be hard. Technologically, it is oversimplifying to think of cars as either "electric" or "gasoline." A better way is to ask what percentage of the total stored energy on board is in the battery or the gas tank. Any car that doesn't have to be cranked by hand is slightly "electric" in this sense: what's that battery for, if not to supply stored energy to start the engine? The hybrids that Toyota and Honda have marketed with great success up the battery-energy percentage to the 20%-30% range. If you run out of gas in a Prius, you won't get very far, but you'll get farther than you will in an Edsel. The new Volt that GM announced moves most of the way toward all-electric. Its large battery will store perhaps as much as 50% of the total energy on board. GM expects that normal commuter usage will draw only on the energy stored in the battery, with the gasoline engine kicking on only for long trips. This will allow people to charge the car overnight at home from the electric grid, which has great systemic advantages over conventional hybrids. Eventually, we may see cars with onboard fuel cells that circumvent the thermodynamic limitation on efficiency that internal combustion engines suffer. These could use hydrogen or possibly biofuels, and would go most of the way toward eliminating harmful tailpipe emissions.

If electric cars are so great, why aren't we all driving them? Historically, as long as the electric car idea has been around, the glass ceiling stopping progress has been the battery. Pound for pound, gasoline contains nearly five hundred times as much energy as a fully charged lead-acid battery. And even the most advanced (and expensive) nickel-hydride batteries are only four times better than lead-acid, leaving gasoline way ahead.

That's the technology in a nutshell. Now, what should engineers be doing with it? Recent advances in materials science and engineering have improved batteries to the point that they are practical—but still expensive—in hybrid vehicles like the Prius. We will have to wait and see if GM, or anyone else, can make and use batteries that are good, reliable, and cheap enough to provide the main source of energy for a commuter-type vehicle that is charged overnight. But growing in importance to overshadow these technical factors is the human appeal factor.

The human appeal factor has to do, not with the technology itself, but how people perceive it. For example, you can show through chemical analysis that some organically-grown food products are scientifically indistinguishable from their non-organic counterparts. Knowing this, some people will still buy organic products. You can view their purchases as a kind of vote in the marketplace for a certain way of living. The human-appeal factor is in play when people bypass clothing made under sweatshop conditions for essentially the same quality of clothes (at higher prices) made under better labor conditions.

With all the problems in the Mideast and other oil-producing regions, more people are making the connection between the kind of car they drive and the international political situation. Engineers who ignore this objective, testable fact (if poll results can be said to be objective and testable!) and concentrate only on some engineering-friendly factor such as efficiency or cost, will find themselves missing a few boats on down the line, if not right away.

Should all engineers be political wonks instead? By no means! Generally speaking, the kind of personality who finds delight in making and dealing with things is not all that well suited to a life in politics, although there are exceptions. But a technologist who ignores the desires and perceptions of the marketplace, and the political and social effects of a technology, is missing an important part of the picture, a part no less important than the technical aspects.

Good people can differ over the questions of whether electric cars should be in our future, whether the marketplace or the legislatures should decide this question, and whether GM is serious this time or just has another trick up its collective sleeve. But to ignore all but the technical aspects of the questions is to lose a little of your humanity, and to become a little more like the machines you are designing.

Sources: An article on the introduction of the Volt and related electric-car news was written by John O'Dell of the Los Angeles Times, and appeared in the Boston Globe online edition on Jan. 14, 2007 at An advocacy group for electric vehicles maintains a website at The data on the comparable energy content of batteries and gasoline was obtained from a table at You can see a picture of the Smithsonian's EV1 at

1 comment:

  1. i notticed taht you have no comments even though this is a well thought out article with many good points. also im using it in a paper so i thought id give u some recognition (other than my bibliography) so thanks for the point of view!