It would seem pretty obvious that a site called Green Car Reports would cover zero-emission vehicles that will soon go on sale from major global automakers.

But cars powered by hydrogen fuel cells turn out to be as controversial as plug-in electric cars, albeit for different reasons--and among different constituencies.

So it's appropriate to explain why we cover this particular set of vehicles, just as we did last year in laying out why we cover large pickup trucks.

ALSO SEE: Why Green Car Reports Writes About Full-Size Pickup Trucks

First, pretty much everyone agrees that zero-emission vehicles are a good idea.

One way to build a car without a tailpipe is to power it only with a battery that's recharged from grid electricity. Indeed, there are now roughly half a million plug-in vehicles on the world's roads.

2015 Hyundai Tucson Fuel Cell at hydrogen fueling station, Fountain Valley, CA

2015 Hyundai Tucson Fuel Cell at hydrogen fueling station, Fountain Valley, CA

But battery-electric cars are perceived to have drawbacks--including recharging time--and it's unclear whether the largest, heaviest vehicles can practically be powered by batteries alone.

For a few decades now, most global automakers have had research and development projects to test the practicality of electrically-driven vehicles with only small battery packs.

Instead, their electricity is generated by fuel cells that turn oxygen from the atmosphere and compressed hydrogen into electricity and water vapor. (Technically an emission, but so what?)

The first Hyundai Tucson Fuel Cell crossover utility was leased this spring in southern California.

Both Toyota and Honda are expected to follow suit, offering small numbers of hydrogen fuel cell vehicles for lease in limited regions of the country between now and 2020.

But unlike electricity, which reaches every household and building in some form, hydrogen will require the construction of expensive dedicated fueling sites.

The hydrogen has to be produced by using quite a lot of energy to break down a feedstock (water, natural gas, or other hydrogen-carrying compounds) to get pure hydrogen (H2), which then has to be compressed and transported to the fueling locations.

DON'T MISS: Toyota, Honda, Hyundai Fuel-Cell Cars: How Many Will Be Sold?

The general consensus is that using the same amount of electricity with the same carbon footprint to produce hydrogen, or to recharge a battery, gets you more miles in the electric car than in the hydrogen powered car.

Finally, there's the compliance-car issue. In the short term, hydrogen vehicles are being put on the road largely to comply with California's zero-emission vehicle rules, not because there appears to be noticeable market demand for them.

Honda FCEV Concept, 2013 Los Angeles Auto Show

Honda FCEV Concept, 2013 Los Angeles Auto Show

These are all rich issues that deserve greater exploration. From our point of view, what better place to do so than on Green Car Reports?

Yet a small portion of our readers have objected to such articles, seemingly on the grounds that fuel-cell vehicles are a sham, a delaying tactic, and built by makers determined to continue selling gasoline vehicles as long as possible.

All of which may be true.

But we feel such issues are best debated in the open, robustly (but politely and respectfully).

MORE: Can Hydrogen Fuel-Cell Vehicles Compete With Electric Cars?

We're not going to suppress coverage of any type of vehicle because (some) readers don't happen to like it.

Perhaps the most comprehensive summary of the issues comes from Joan Ogden, a professor of environmental science and policy in the Institute of Transportation Studies at the University of California--Davis.

2016 Toyota Fuel Cell Sedan

2016 Toyota Fuel Cell Sedan

Ogden was the lead author of a report looking at exactly what it would take to make hydrogen competitive with gasoline as a vehicle fuel.

“Hydrogen faces a range of challenges, from economic to societal," Ogden wrote, "before it can be implemented as a large-scale transportation fuel."

“The question isn’t whether fuel cell vehicles are technically ready: They are."

"But how do you build confidence in hydrogen’s future for investors, fuel suppliers, automakers, and, of course, for consumers?”

Those questions are why Green Car Reports writes about hydrogen fuel-cell vehicles.


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