"I get the thumbs up all the time from people who realize it might not be the vehicle for them but that somebody has to buy it."

Church is one of only a few thousand clean-car owners around the world, but eventually he could be part of a crowd. After years of fits and starts, auto engineers are making serious strides toward bringing ecofriendly vehicles to showrooms. The EV1, introduced in California and Arizona late last year, is but a ripple in the wave of emerging automotive technologies seeking cleaner options beyond the internal combustion of gasoline. Still slowing the wave, however, are issues of cost and convenience. All-electric: Boasting zero emissions and featherweight frames, the EV1 and similar models developed by other major carmakers are regarded as the environmentally sound future of motoring. But while they are relatively quiet and spew no pollution out the tail pipe, so far they suffer from high cost and limited range. Church pays $399 a month for his EV1. If he wanted to buy it outright, the price tag would be $34,000. Toyota's RAV4 EV, based on one of the company's popular sport-utility vehicles, leases for $1,680 a month in Japan and sells for $42,000. Nissan, which keeps 30 electric vehicles on hand in Japan for lease to company fleets at $2,800 a month, has not even tried to sell the model to individual customers.

Electric cars accelerate swiftly and can drive at highway speeds, but they don't go all that far before they need recharging. Toyota's RAV4 EV, for example, uses 24 nickel-metal hydride batteries, which limits the range of the cars to 200 km on a single charge. That can be inconvenient, since Japan has only 46 recharging points for electric cars, including just two in Tokyo that are available for public use. Worse, fully recharging the battery takes eight hours--easy enough to do overnight but not while on a long, continuous trip. As battery technology improves, though, all-electric cars could someday fulfill their immense promise. Hybrid: More practical in the short run may be so-called hybrid cars that have both a battery-driven motor and a gasoline engine--with the ability to switch back and forth between the two power systems. Such vehicles, soon to be introduced by Toyota and later by Nissan, try to balance environmental interests with practicality. (Audi is close to selling a diesel/electric version.)

When the hybrid drives at medium and high speeds, the gasoline engine powers the wheels, as in a regular car. But in stop-start city driving, when the engine would be running at a low efficiency, it is shut off, and the hybrid becomes an electric car, getting power from the battery. For swift acceleration, the engine and electric motor combine to deliver maximum power. When the battery runs low, the gasoline engine generates electricity for recharging. And during braking or deceleration, the energy of the wheels turns the electric motor, so power that would be dissipated as heat is funneled back into the battery. The power flow is controlled by an inverter--a central unit managed by an electronic motherboard crammed with microchips. By alternating automatically between the two motors according to need, the cars can, for example, go into electric mode in the city, thereby not adding to urban smog, and then switch to gasoline mode for longer stretches on the highway. The net result is a spectacular increase in fuel efficiency and far less pollution than from regular cars. There's no hassle either: recharging goes on while the car is in operation, and fuel is as close as the nearest gas station.Toyota is expected to deliver its hybrid later this year for no more than $20,000 a model--only $4,000 higher than a Corolla.

Fuel cell: A third approach is to power cars with fuel cells, which combine hydrogen with oxygen to form water vapor and electricity. Mercedes-Benz has incorporated a fuel cell developed by Canada's Ballard Power Systems into its experimental NeCar II (short for New Electric Car II; NeCar I was a truck prototype).

At the cell's center is a membrane coated with a platinum catalyst and an electrode made from gas-permeable graphite paper.

Positioned on both sides of the catalyst are graphite plates with fine gas channels milled into them. The channels on one side of the membrane are fed with hydrogen, while those on the other side receive compressed oxygen. The catalyst sets in motion a reaction that causes the hydrogen side of the cell to become negatively charged, and the oxygen side positively charged, thus generating an electric current. Because hydrogen fuel is not yet widely available, the first fuel-cell cars will probably carry another fuel, possibly methanol, to help produce hydrogen.

None of these autos is totally nonpolluting because of the fossil fuels generally used to generate the electricity and hydrogen needed to run the engines. But if the original power source becomes the sun or the wind, then the cars of the future will be much friendlier to the atmosphere than what's on the road today.

--With reporting by Sebastian Moffett/Tokyo and Katherine Schmidt/Bonn