In the Yale School of Forestry and Environmental Studies’ Prius-filled parking lot, there is a lone Toyota Highlander SUV.

Marian Chertow SOM ’81 FES ’00, an associate professor of industrial environmental management at the environment school, drives the vehicle, which has been retrofitted as a fuel cell car as part of a nationwide pilot program run by Toyota to test its hybrid vehicles. In Connecticut, the automobile company is working with Wallingford-based fueling station chain SunHydro to raise awareness of hydrogen’s viability as a fuel source, said Larry Moulthrop, vice president of Proton OnSite, Sun Hydro’s equipment provider.

The program, which began in March, aims to raise public awareness of hydrogen fuel cars by loaning the cars to certain drivers who can use the vehicles and share their experiences with others. SunHydro supplies the 10 Connecticut-based participants with the hyrdogen fuel for their vehicles, and the cars are outfitted with stickers boasting that the vehicle is “powered by sun and water.”

“SunHydro is gaining real-world operating experience with our fueling equipment, and Toyota is gaining real-world operating experience on their vehicles, so the value to both companies is quite significant,” Moulthrop said.

Chertow, who has driven the car since March, fills up her vehicle at SunHydro’s hydrogen fueling station in Wallingford, the only one of its kind in the state. She said the filling station is also environmentally friendly: it gets 20 percent of its power from solar energy. The filling process is similar to that of a normal gas station, but is hands-free, Moulthrop said. The dispenser in the station will test the car’s pressure and fill it up to its maximum level, he added. Although driving 16 miles to fill up the tank is a “slight hassle,” Chertow said she can travel 360 miles on a full six-kilogram tank of hydrogen, making her vehicle more efficient than many cars.

The cost of fueling a hydrogen car currently works out to be 16 cents per mile, the same as that of an average gasoline-powered car, Moulthrop said, adding that he expects the price to go down over time.

As they become commercially available in limited production by 2015, SunHydro and other hydrogen visionaries advocate for construction of clusters of filling stations in major metropolitan areas to service fuel cell vehicles, Moulthrop said. Chertow’s Toyota model is a preproduction model, and most major auto manufacturers have announced plans to bring production fuel cell vehicles to auto showrooms by 2015, he said. He added that, once on the market, these cars will be sold in areas where there is a larger infrastructure, and that he expects limited sales in the northeast and a larger number of vehicles in the Los Angeles basin, where there are already several fueling stations.

Chertow, who usually drives a Prius, said the Toyota runs much like other hybrid cars in that both are quiet because the energy used is created by a fuel cell, not a mechanical engine.

Fuel cell cars, Chertow said, run on a continuous chemical reaction that uses the hydrogen source to power the vehicle. This “very clean technology” reduces pollution because the car emits water vapor rather than pollutants, she added.

“If you wanted to, you could drink that water, although I don’t think anyone’s thirsty enough to want to,” Moulthrop said.

Chertow said driving the hydrogen-powered vehicle has elicited curiosity from strangers and colleagues, adding that several of her neighbors have since spoken with her about purchasing hybrid cars.

“Everyone in the School of Forestry has a real penchant for hybrids,” said Reid Lifset SOM ’89, an FES associate research scholar and resident fellow in industrial ecology. “There’s been a lot of hybrids here for a while, so it wasn’t quite as striking to see a fuel cell car here than it would in other places.”

Lifset, who has driven a Toyota Prius for the past decade, said factors such as cost and quality would factor into his decision to purchase a hydrogen-powered car in the future. However, he added, “the fact that it would be a fuel cell [and therefore less-polluting] car would be very attractive to me.”

Chertow stressed the importance of participating in pilot programs such as this one to help shape development.

“You learn what’s coming and where the future lies, and you make it less scary for others because you’re doing it,” she said. “I think the whole experience has been very positive for me.”

The idea of mass-produced hydrogen fuel was first popularized by a 1970 University of Michigan report.