Engines of Change The Holy Grail(圣杯) for Automakers I am driving through downtown Washington, D.C., in a white GM minivan with friendly blue-bubble paper decorating the sides. It's emitting no toxic chemicals and the engine seems to purr(发出隆隆声) rather than growl. I am driving a hydrogen-powered automobile—so clean, you can drink from the exhaust pipe—and it's a smooth, energetic ride. It's also the Holy Grail for automakers, environmentalists, political leaders—and, most important, drivers everywhere, whether or not we realize it yet. What's not to like about a vehicle that combats global warming, offers hope of weaning(使戒掉) the world off Mideast oil, and could save on fuel costs? More than anything, though, the development of the hydrogen car, along with other alternatives, is a response to one unsettling fact: The world will one day run out of oil. And that day may arrive sooner than most of us would think. Industry experts at the Association for the Study of Peak Oil and Gas (ASPO) predict that by 2008, we may have extracted half the available global supply of oil. While it took us the better part of the last century to reach this halfway point, it will take significantly less time to consume the rest. With more industrialized countries, more cars, trucks and buses, and more demand than ever for home heating and appliances—just think China—oil could reach depletion more quickly than we once assumed. So the race is underway to find affordable fuel alternatives, as well as new ways to conserve our remaining oil. For car manufacturers and a growing number of consumers, the future is now-in the form. of the latest generation of hybrid vehicles. Toyota, Honda and Ford have led the charge with technology that pairs a small gasoline engine with an electric motor that actually powers the car without high levels of pollution. The electric motor and gasoline engine is more efficient than a combustion(燃烧) engine. According to the Alliance to Save Energy, in 2004, SUV drivers spent about $1,225 on fuel, while passenger cars cost $976 to run. Hybrid drivers only spent between $350 and $450. Also, hybrids have solved a big drawback of energy-efficient electric cars, which need to be recharged regularly literally plugged into a power source. Hybrids like Honda's Insight, Civic and Accord, and Toyota's Prius, charge the battery as you drive. Plus, some can travel more than 600 miles on a tank of gas. To lure people to buy these cleaner, more efficient cars—hybrids, the federal government is offering owners a one-time tax deduction. Local governments are offering incentives too. Hybrid owners in Los Angeles receive parking exemptions in Connecticut, residents whose energy-efficient cars get at least 40 miles per gallon are exempt from the sales tax on the car Pennsylvania owners are eligible for a $500 discount at purchase and in Virginia, hybrid drivers can take advantage of the HOV (high-occupancy vehicle) lane—no matter how many passengers are on board. According to Bradley Berman, editor of HybridCars.com, 88,000 of these automobiles were sold in the United States last year—that's nearly double the previous year and about ten times as many sold in 2000. This year alone, the chic(时尚的) Prius is on track to sell some 45,000, despite six-month waiting lists. Reducing U.S. Oil Consumption Even as more hybrid cars hit the road, the technology is a key element in an exciting new project, one that could hasten our transition to a hydrogen-fuel economy. The Rocky Mountain Institute (RMI), a nonprofit organization dedicated to energy policy, has launched a research center with the sole purpose of creating the 'Hypercar.' This vehicle's design is what sets it apart. Hypercars are formulated to make the most of an ultra-light construction, low-drag aero-dynamics and hybrid-electric drive trains to achieve much greate