The basic principle behind hydrogen fuel cells is fairly simple: Hydrogen atoms are stripped of their electrons to generate electricity and then combined with oxygen to form water as a by-product. Mainstream deployment of fuel-cell vehicles, though, has proved to be complex. Compared with liquid fuels, hydrogen is tough to transport and store. And without a meaningful number of vehicles on the road, there's been no incentive to build hydrogen fuel infrastructure. Now new initiatives in California and across the U.S. are pushing for a long-awaited expansion of the refueling network. And with the debut of three promising hydrogen-fuel-cell vehicles from Honda, Hyundai, and Toyota, consumers will have new options beginning in 2014. Are we finally seeing the dawn of the hydrogen age? Not so fast.

Why Now?

The current hydrogen push has less to do with consumer demand than with government incentives that treat fuel-cell vehicles (FCV) as equal to or better than electric vehicles. In California the combination of 300-mile range and fast refueling gives fuel cells the maximum available zero-emission vehicle (ZEV) credits. That makes it easy for a manufacturer to meet the state's ZEV mandate with fewer cars. On the federal level, both FCVs and EVs get an EPA credit multiplier of 2.0 beginning in 2017, which means that sales of either type of car confer a disproportionate benefit on the ledger for an automaker's entire fleet. In response, manufacturers have formed several high-profile partnerships, including Ford/Daimler/Renault-Nissan, BMW/Toyota, and GM/Honda to develop the vehicles. On the fueling side, a recent infusion of $20 million of funding per year has expanded the California Fuel Cell Partnership's plan to 100 statewide refueling stations. The Department of Energy's H2USA organization wants to use California's efforts as a blueprint for the rest of the nation.

Can I Buy a Fuel-Cell Car?

In the past, fuel-cell vehicles have only been available in the hundreds. The three new FCVs slated for production this year and next will increase the volume to thousands, but they will be available primarily in California, where most of the country's hydrogen stations exist. According to Alan Baum, an automotive analyst at Baum and Associates, even if the stations proliferate, fuel-cell vehicles, like EVs, won't dominate the market. "It's not going to be a widespread technology, and for that matter it doesn't need to be," he says. "We're doing an all-hands-on-deck strategy."

Are They Practical?

Not according to Tesla and SpaceX founder Elon Musk, who says fuel cells are more of a marketing ploy than a realistic solution. Nissan CEO Carlos Ghosn agrees: "Knowing all the problems we have with charging [EVs], where is the hydrogen infrastructure?" Both men have a bias toward electric vehicles, but the infrastructure issue is a big one. With the current cost of a hydrogen filling station at more than $1 million, neither the government nor the corporate world has any plans for a rapid expansion of the filling network. "We've got electricity everywhere," Baum says. "Putting in 240-volt charging units requires some effort and expense, but it's not game changing. Putting in hydrogen is."

Where Does the Power Come From?

Kyle Bean and Mitch Payne

Here's the abridged version: Compressed hydrogen from the storage tank (A) is stripped of its electrons in the fuel-cell stack (B), creating electricity. A power-control unit (C) orchestrates the flow of energy from the stack to the battery (D), which powers the electric motor that moves the car. The battery ensures full power during acceleration until the fuel cell reaches peak voltage. Got all that?

Are They Safe?

Yes. Stringent requirements established by the Department of Transportation (DOT) and Society of Automotive Engineers (SAE) ensure that the technology is safe. Automakers are required to build robust hydrogen storage tanks that not only hold the fuel at up to 10,000 psi but also withstand arcane-sounding trials such as "bonfire" and "gunshot" tests by the DOT. Tanks are usually made of several layers of carbon fiber wrapped around aluminum or polyethylene liners, and many are also protected by external layers of steel. Regulations covering PRDs (pressure-relief devices) govern both temperatures and pressures at which gas is released, typically well below what is standard for safe operating conditions.

How Green are Fuel Cells?

It depends on where you look. The only tailpipe emission from an FCV is water, but the process of creating hydrogen fuel—just like that of formulating gasoline or generating current for an electric vehicle—has an environmental impact. More than 90 percent of hydrogen today is created using a natural-gas-reforming process involving steam and methane, which reduces CO 2 emissions from "well to wheel" by approximately 60 percent, compared with the process of creating gasoline. So, carbon dioxide is still released into the atmosphere—it just happens before the liquid hydrogen gets to your tank. Incentives and mandates encourage a cleaner hydrogen-creation process: The state of California requires that 30 percent of H 2 supplied for transportation come from renewable sources, which can include wind, solar, and biomass material.

What About Refueling?

One advantage of FCVs is that they can travel farther and restore range faster than most current EVs. Refueling is simple: Once a nozzle with a snap collar is securely mated and locked to your car, the transfer of hydrogen begins with a brief hissing sound, followed by a 3- to 5- minute fill-up. However, it takes considerably longer for a filling station to restore the pressure required to service the next vehicle, so current setups can only refuel six or so cars per hour.

So, is Hydrogen Happening?

"When you have several major carmakers saying we're going to invest in this, that's significant," Baum says. But vehicles are just one piece of the puzzle. Every other player in the hydrogen supply chain, such as the service station industry, needs to invest heavily. Until then, refueling options and vehicle choices will remain extremely limited, with no guarantee of expansion. Which is to say that hydrogen-fuel-cell cars will be a minor footnote in terms of overall vehicle sales for the foreseeable future. For all but the earliest of adopters, hydrogen as a prominent fuel alternative remains somewhere on the horizon.

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