Under the agreement, which will go to the Common Council next Tuesday, Shell oil company would build the facility and fuel pump at the Kensico Avenue garage to supply three Toyota cars and two General Motors trucks at no cost to the city. Shell would donate the fuel, and the city has applied for a $324,000 grant from the state to buy the five vehicles.

The hydrogen fueling station would be one of five that Shell has planned nationwide, including one already operating near Washington, D.C. Shell has proposed another station in Greenburgh, and two others are planned for the Los Angeles area, said Tim O'Leary, a spokesman for Shell Hydrogen in Houston, a division of the Dutch oil giant.

O'Leary said Shell and GM chose White Plains and Greenburgh because they are in a metropolitan area with demographics that suggest residents would be open to the technology and could afford it. A relatively high percentage of residents in both municipalities already drive hybrid cars, which run on batteries and gasoline, such as Toyota's Prius, O'Leary said.

"They're the kind of communities that have the wherewithal and predisposition to purchase new-technology vehicles," O'Leary said. "That's the kind of community we want to be in."

In Greenburgh, town officials have been reviewing the hydrogen fueling station that Shell wants to build on Central Avenue since February.

O'Leary said he hoped things would move more quickly in White Plains, a city that has been using alternative fuels since 1978, when it was the first in the state to begin pumping ethanol into city cars and trucks. Today, White Plains fuels a street sweeper and five cars on compressed natural gas under a program that made it the first city in New York to win a federal "Clean City" award.

White Plains Public Works Commissioner Joseph "Bud" Nicoletti said he enjoyed setting examples for other places that were considering clean-emission alternative fuels, but he added that, in the end, "it always comes down to economics." Over the years, the city's demonstration projects have been funded by companies and other governments interested in developing the technologies, providing city garages with trucks, snowplows, cars and other vehicles at little cost.

Shell would build the five hydrogen plants and fuel pumps in a partnership with General Motors, under the federal Hydrogen Demonstration Validation program. The program has been successful enough that GM recently announced a second generation of hydrogen cars, called Equinox, although they also will be demonstration cars that will be too expensive to sell to consumers. With the technology already proven, O'Leary said the challenge now was to make hydrogen vehicles affordable and to "propagate the infrastructure," or build enough fueling stations around the country to make them convenient.

"Although we're using tried and true technology, we're still learning things about the economics of this," O'Leary said. "But everything we've seen and done so far leads us to believe that once fuel-cell vehicles reach the commercial stage, we'll be there and able to provide hydrogen at an attractive price."