Are Hydrogen Vehicles Part of the Solution?

A Mercedes-Benz hydrogen fuel-cell vehicle. (Green Car Reports)

A Mercedes-Benz hydrogen fuel-cell vehicle. (Green Car Reports)

While hydrogen vehicles are one of several ‘green’ vehicles being promoted, there’s debate about whether they are environmentally friendly

By TIM FAULKNER/ecoRI News staff

Hydrogen-powered cars recently arrived in the United States, but it's unclear if the vehicles are good for the environment or if drivers will embrace them.

The first hydrogen-fueled cars, made by Hyundai, arrived in California on May 20. Honda and other car manufacturers expect their hydrogen vehicles to arrive in the Northeast next year.

Hydrogen vehicles are one of several "green" vehicles promoted by the eight-state, zero-emission vehicle challenge, known as the Zero Emission Vehicle (ZEV) mandate. The eight-state coalition includes Rhode Island, Massachusetts, Connecticut, Vermont, New York, Maryland, California and Oregon. The non-binding program seeks 3.3 million battery-electric, plug-in hybrid or hydrogen-fueled vehicles on U.S. roads by 2025.

To get there, the states plan to install charging and alternative-fuel fillings stations, increase ZEVs in government fleets and offer financial incentives to increase use by businesses and everyday drivers. Rhode Island promoted hydrogen vehicles and its involvement in the ZEV program during a forum last month in Providence.

Because of engineering constraints, hydrogen vehicles can't run on pure hydrogen. Hydrogen ZEVs are instead hybrids that use hydrogen fuel cells to power an electric engine.

Of course, hydrogen fuel-cell vehicles need hydrogen fueling stations. Currently, there are two publicly accessible stations in New England, located in Billerica, Mass. and Wallingford, Conn. A third is expected this year in Braintree, Mass. A 2012 study for Rhode Island suggests 30 potential hydrogen fueling stations across the state. Each station costs about $1 million.

Although hydrogen is the most abundant element in the universe, it's scarce in its pure state. Creating hydrogen as fuel requires energy. A process using steam, called reformation, is the most commom method. Other methods extract hydrogen from water by using natural gas and through a process called electrolysis. Natural gas, obviously, is a fossil fuel, while electrolysis and reformation typically require other fossil fuels or electricity from the power grid. Prototypes systems, however, use renewable energy to make hydrogen. 

According to the federal Alternative Fuels Data Center, hydrogen created from natural gas releases fewer greenhouse gas emissions than the average gas-powered car, while hydrogen derived from electrolysis produces more.

However, a study by the California Energy Commission says hydrogen obtained from electrolysis generates 33 percent fewer greenhouse gases relative to gasoline. The discrepancy may be from assumptions that use California's relatively green electricity supply and expected advancements in making electrolysis more energy efficient.

A study by the U.S. Department of Energy says the New England electric generation mix also has enough renewable energy to make electrolysis the greener choice for hydrogen production. A report by the National Renewable Energy Laboratory says hydrogen produced by natural gas or electrolysis releases fewer greenhouse gases than natural gas-powered vehicles.

“Based on this information, hydrogen fuel produced by natural gas or by electrolysis is a greener, cleaner fuel source than that produced from petroleum,” said Marion Gold, commissioner of Rhode Island’s Office of Energy Resources.

ENE, an environmental advocacy group, applauded the ZEV mandate. But ENE staff attorney Mark LeBel said it’s too early to know which, if any, hydrogen-production technology will be adopted.

“The hydrogen for fuel-cell vehicles can be made in many different ways, some of which are environmentally friendly but some of them are not," he said. "At this point, it's really hard to say how the market for hydrogen will develop, so it's difficult to figure out greenhouse gas impacts with any rigor.”

Plug-in electric vehicles, LeBel noted, curb greenhouse gas emissions by 60 percent compared to a gas-powered vehicle. “By contrast, with EVs, we already have an electric system so we can get a pretty good handle on the impacts," he said.

According to the federal government, the intent is to offer several zero-emission vehicles and see which ones are accepted. This may include passenger vehicles, buses, delivery vans and/or tractor-trailers, since each has unique energy needs. Hydrogen fuel cells appear to offer environmental benefits for vehicles that currently burn diesel fuel to generate electricity to cool buses and refrigerated trucks.

“We’re not really betting the farm on one certain technology,” said Greg Moreland, a consultant with the U.S. Department of Energy. “I'm hopeful this will be a solution."  

Other ideas tested by the National Renewable Energy Laboratory power electrolysis with solar PVs and wind power during off-peak hours. Both concepts, however, are still in their infancy.

“The bottom line is people aren’t going to buy these vehicles unless they make sense,” said Joel Rinebold of the Connecticut Center for Advanced Technologies.

The May 28 conference was sponsored by Ocean State Clean Cities, a state and federally sponsored advocacy program that promotes alternative and renewable-energy fuels.