As automakers compete for market share, they are also striving to become "greener."
A host of more-environmentally friendly vehicles are either showing up in showrooms or are in development. Some of the technologies are catching on, while others remain years from reaching mass production, if ever.
Drivers can already buy hybrids, which run on a combination of electric power and gasoline. Edmunds. com lists 15 hybrid models on the market, and more of them are coming. Demand for hybrids has fluctuated with gasoline prices, and they account for a small share of new-vehicle sales.
Meanwhile, millions of so-called "flex fuel" vehicles are on the road, capable of running on gasoline or a fuel blend of up to 85 percent ethanol, which is also known as E85. Some drivers might not even know they own such versatile vehicles.
E85's advocates say the fuel helps reduce dependence on foreign oil, but its detractors note that E85 gets weaker mileage results than gasoline. Nationally, more E85 outlets are opening, but they remain a tiny percentage of the overall total, and the fuel is virtually impossible for motorists to find at fueling stations in New York state.
Biodiesel, which refers to renewable fuels that can be burned in a typical diesel engine, is another promising option, said Philip Reed, consumer advice editor for Edmunds.com.
Still in development by the automakers are "plugin hybrids" and hydrogen-powered cars.
GM is working on a "plug-in hybrid" version of its Saturn VUE hybrid. It would use an improved battery that plugs into a conventional power outlet for recharging, and produce better mileage results than an existing hybrid.
GM's chief executive officer, Rick Wagoner, has called a plug-in hybrid a "top priority program" for GM. "The technological hurdles are real, but we believe they're surmountable," he said in a speech at the Los Angeles Auto Show.
Reed said a plug-in hybrid would appeal to customers who want an electric car, but still want backup from gasoline power in case the car's electric power supply runs out. He predicted the first such plug-in hybrids would hit the marketplace in about three years.
For GM, he said, a plug-in hybrid would help blunt negative publicity it received from the film "Who Killed the Electric Car?", about the demise of the EV1 electric vehicle, and would give GM an opportunity to burnish its green credentials.
"They would love to one-up Toyota, which has taken the lead on hybrids," Reed said.
Experts agree that hydrogen-powered cars are still years away from commercial production.
"[Hydrogen] is really promising and really intriguing and everyone is doing a lot of work on it, but it is not going to happen tomorrow," said John McElroy, an auto industry expert who is editorial director of Blue Sky Productions.
An obstacle to the emergence of hydrogen-powered vehicles is that the nation's hydrogen infrastructure is developing as a "cottage industry," he said. A national effort would help create the infrastructure in a more cohesive way, McElroy said.
Meanwhile, some automakers are rolling out demonstration models of hydrogen-powered cars that are stoking interest in the vehicles' long-range potential.
GM is deploying a "test fleet" of 100 fuel-cell powered Chevy Equinoxes. Honda says it is moving closer to limited production of a vehicle based on its FCX concept. BMW is making a limited number of Hydrogen 7 sedans, and Ford has shown off a fuel-cell powered Explorer, among others that are taking steps.
Reed said he didn't expect hydrogenpowered cars to reach the mass-production phase for at least seven or eight years, if they ever get to that point.
Compressed natural gas is another alternative fuel option, as demonstrated by Honda's Civic GX. But other automakers have shown little enthusiasm for natural gas technology, and refueling options for the public remain limited.
So which kinds of alternative-fuel vehicles might achieve widespread acceptance? McElroy said he believes ethanol is poised for big things.
"Ethanol is out in front and could grow a lot," McElroy said. Locally, investors are planning to open an ethanol plant in South Buffalo, while another is under construction in Orleans County.
Reed said he sees great potential for biodiesel, since a diesel-powered vehicle wouldn't need modifications to run on it.
As the automakers develop new technologies, they still need to find ways to make them more affordable and practical for mass production. In some cases, a lack of widely available fueling stations could be an obstacle to mainstream use. And prospective buyers will no doubt want to see how well an alternative-fuel vehicle's performance stacks up against its gasolinepowered cousin.
Reed said he believes consumers would be more willing than some people think to go a little out of their way to fuel up and drive something that benefits the environment and helps reduce dependence on imported oil.