Forget the old quip that hydrogen-powered vehicles are five years in the future—and always will be. They’re almost here.
This June, a test fleet of 10 lightweight vehicles [pictured above] running on hydrogen will start delivering mail for La Poste, the French postal service, to the towns of Audincourt and Lons-le-Saulnier, both in eastern France near the Swiss border.
Electric motors on the two rear wheels will be powered by fuel cells that generate electricity from hydrogen’s reaction with atmospheric oxygen. MobyPost, a public-private consortium with partners (including La Poste) in France, Germany, Italy, and Switzerland, developed the vehicle, with some European Union funding.
“Hydrogen is the clean fuel of the future,” says Abdesslem Djerdir, MobyPosts’s vehicle development supervisor and vice director of the Fuel Cell Lab at the Technological University of Belfort Montbéliard (UTBM), one of MobyPost’s French partners, which coordinates MobyPost’s activities. “Hydrogen-powered vehicles don’t pollute the air or add carbon to the atmosphere; their only emission is water vapor. That’s especially important in towns and cities, where MobyPost’s vehicles will be used.”
IEEE Member Djerdir, an associate professor at the school, is also an IEEE distinguished lecturer. He will be a speaker at the IEEE European Prospects on Transportation Electrification–Infrastructure and Power Train Distinguished Lecturer Series, to be held in October at UTBM.
“The event will focus on a critically important domain of transportation electrification R&D in Europe: infrastructure,” he says. “These include vehicle-to-vehicle, vehicle-to-electric grid, and vehicle-to-infrastructure communications and power trains for electric vehicles, plug-in hybrid EVs, and fuel-cell vehicles (FCV).”
For now, the fueling infrastructure, or lack thereof, is the main obstacle to hydrogen power’s adoption. Hydrogen filling stations are few and far between anywhere in the world, aside from a small cluster in Southern California. MobyPost’s solution is to produce hydrogen right in its vehicles’ garages, extracting hydrogen from water by electrolysis. This works because, unlike passenger cars and other wide-ranging vehicles, urban delivery vehicles cover relatively few kilometers and can refuel each day at their home garages, with no need to search for filling stations. MobyPost is not alone in realizing this, which is why US $6 million of the U.S. Department of Energy’s recent $7.2 million in grants to develop fuel-cell applications went to delivery companies like FedEx and to a developer of delivery trucks for United Parcel Service.
The impetus for MobyPost came from La Poste, whose current delivery vehicles include bicycles and trucks. It wanted a nonpolluting vehicle small enough to handle France’s narrow streets but large enough to carry more mail than the scooters it will replace. It also had to be designed for postal use. For example, the driving position and controls are placed to facilitate a mail carrier’s movements, and there are no doors to get in the drivers' way as they go in and out to make deliveries.
The MobyPost vehicle carries about 100 kilograms of mail, more than twice as much as La Poste’s scooters, according to Djerdir. With four wheels, it’s more stable than a scooter, especially in snow. Its windshield and roof provide some shelter in bad weather. Ducati Energia, in Bologna, Italy—another MobyPost member—will build it.
MAKING THE HYDROGEN
Hydrogen power is only as “green” as the energy source used to pry it loose from the compounds (such as water or methane) it’s locked into, points out Michel Romand, MobyPost’s project coordinator. MobyPost will get that energy from solar panels on the garages’ roofs.
“It’s a sun-to-wheel concept,” he says.
The hydrogen generation process and the fuel cell are each only 50 percent efficient, according to Djerdir. “But starting from a free, renewable source such as the sun, it’s not a problem,” he says.
The amount of hydrogen required is small: 1.5 kg, equivalent in energy to a gallon of gas. The vehicle itself weighs less than 350 kg. And since it will only travel locally, a range of 40 km per fill-up is enough.
Not all FCVs have such limited range. Most go farther on a tank than electrics can on a single battery charge. But as Djerdir points out, “The volumetric energy density of compressed hydrogen fuel-cell systems is higher than for any battery scenario, and hydrogen tanks are far cheaper than batteries.”
For that reason, fuel cells are also being used to extend the range of electric-vehicle designs. In a separate project, La Poste and UTBM are refitting small Renault Kangaroo electric postal trucks with fuel cells. FedEx is refitting 20 electric delivery trucks in the United States with hydrogen fuel-cell range extenders. Range is expected to double in both cases.
Since the fuel cell’s output is fairly constant but the vehicle’s power demands vary, all FCVs have batteries, including the ones for La Poste. The batteries buffer the fuel cell’s energy when the vehicle is stopped—postal vehicles make hundreds of stops a day—and augment the fuel cell’s output during acceleration or when climbing hills. These lithium-iron magnesium phosphate batteries are the same type used for other electric vehicles. The MobyPost vehicle needs only one-tenth the capacity of those in other electrics, which would make it substantially smaller, lighter, and less expensive than those in pure-electric vehicles. Unfortunately, says Djerdir, lithium-iron batteries this size are not yet on the market.
Refueling fuel cells takes far less time than recharging batteries, though the exact time depends on the filling-station pressure. MobyPost uses moderate to low hydrogen pressures for safety and to avoid wasting energy compressing it. Refueling therefore takes about 90 minutes, and is done while the drivers are presorting their routes’ mail for delivery.
Pressure in the vehicle’s tank is only about 2 bars (29 pounds per square inch), less than the pressure in most automobile tires, because the hydrogen is absorbed by a metal hydride, a simple hydrogen-metal compound.
“This technology is safer and more efficient than high-pressure storage,” says Djerdir. “Some other vehicles carry hydrogen at 750 bars, which is dangerous. Governments worry about that.”