Quiet, pollution-free and run on the most plentiful element in the universe, the million-dollar prototype vehicle could be laying the groundwork for transportation in a time when fossil fuels are depleted.

The city of Ann Arbor, which already holds the keys to 150 alternative-fuel vehicles, is one of six cities - including nearby Taylor - that will be road testing the Focus by using it in its fleet for the next three years.

"I'm an enthusiast for autos and new technologies, and I am delighted to be a part of this,'' said Ann Arbor City Administrator Roger Fraser.

Driving it isn't much different from driving a normal Ford Focus. Even so, only five city workers, including Fraser, have been trained to use the car, which was delivered Wednesday at an event in Taylor.

The Focus will be part of the normal city fleet and will be used for travel to meetings, inspections and other events in the course of city business. The car will be maintained and insured by the city as part of its regular group insurance for up to $200,000. Ford Motor Co. would make any necessary repairs.

It will be hydro'd up at a pump at the U.S. Environmental Protection Agency's National Vehicle and Fuel Emissions Lab on Plymouth Road in Ann Arbor.

Ford has offered the cars to the cities to gather real-world testing data. (Other cities in the program are Sacramento, Calif.; Orlando, Fla.; Vancouver, B.C.; and Berlin, Germany.) Each car is loaded with sensors that will report information back to the Dearborn-based automaker.

David Wagner, field service manager for Ford's Sustainable Mobility Technologies division, said each car has a "flight recorder'' that allows Ford to monitor everything each car did the day before.

Dave Konkle, the Ann Arbor energy coordinator, said the city would love to put the car in general circulation, but because of its value, Ford is limiting the number of drivers.

The company has trained city mechanics to work on the hydrogen-powered car, which contrary to myth is powered by a fuel less likely to explode than gasoline.

As for potential hydrogen car thieves, the city will take steps to keep the car safe, but Konkle points out that a thief would look conspicuous driving the rare machine with "Fuel Cell'' written on its side, especially when he tried to refuel it.

Ford has developed two different hydrogen fuel-cell vehicles, as well as two other fuel-cell vehicles that run on methanol - a liquid made of carbon, hydrogen and oxygen.

The company even has cars that use hydrogen in a standard internal combustion engine.

The vehicles are among the first in a tiny but growing fleet of fuel-cell cars on American streets.

Wagner said the company intends to make the cars commercially viable in 10 years, but many bugs must first be worked out.

The cars run entirely on electric motors, getting energy from compressed hydrogen that's sent through a fuel cell. Using a catalyst, hydrogen and oxygen interact in the cell and generate electricity, creating water as a byproduct.

Proponents say the technology has great promise to provide a nearly limitless and clean energy source, but it's not without problems.

Water freezes. The car will have to be stored in a heated garage. Hydrogen is hard to squeeze into a gas tank, so the range is about 200 miles per fill-up.

Right now, most BP gas stations don't have a hydrogen island. And it costs about $5 per gallon-equivalent.

Note that "most'' BP stations don't have hydrogen islands. The global oil giant, which also is the leading solar panel producer in the world, has been a front-runner in developing alternative energy.

The company is partnering in a U.S. Department of Energy program that is pairing the cars with municipalities. As part of that program, BP has installed a hydrogen-fueling station at a station in Sacramento and is building fueling sites in Taylor and at the NextEnergy facility in Detroit.

Construction of a hydrogen production and delivery system is one of the primary roadblocks to mass production. Hydrogen is readily available, but producing it and getting it to service stations might require a massive investment in new infrastructure.

According to the industry magazine Fuel Cell Today, there will be 500 fuel-cell vehicles on the road by the end of 2005.

Not surprisingly, California leads the way with 90 fuel-cell passenger vehicles and buses on the road and 16 hydrogen-refueling stations, according the April 2005 Fuel Cell Catalyst newsletter.

California plans to have 300 such vehicles on the road in the next two years.

The promise of hydrogen as a future fuel has captured the imaginations of hundreds of university researchers and dozens of companies around the world.

University of Michigan researchers have been focusing on fuel cells, looking at the production of hydrogen and how to make fuel cells cheaper to produce, said Levi Thompson, director of U-M's hydrogen technology laboratory.

This fall, U-M President Mary Sue Coleman announced an expansion of U-M's examination of alternative energy sources. Faculty from several disciplines will study the risks and challenges of moving the country from using petroleum-based fuel to hydrogen power.

And in Ann Arbor, T/J Technologies Inc. - a spinoff co-founded by Thompson, who serves as chief technology officer - Adaptive Materials Inc. and others have received federal grants to develop fuel-cell technology.

But it may be some time, if ever, that fuel-cell cars dominate the roadways.

In the near term, other alternative fuels - including biodiesel, a clean-burning fuel made from soybean oil, and ethanol, a corn-based alcohol fuel - are cheaper and easier to use with existing automotive technology and infrastructure.