Questions around the prospects, desirability, technology, and practicality of hydrogen fuel-cell vehicles will likely get a lot of attention in coming months.

At the Los Angeles Auto Show next week, more details on the Toyota Fuel Cell Sedan--which may gain a new model name (rumored to be Mirai)--will be released to the public, including its interior design.

DON'T MISS: 10 Questions On Hydrogen Fuel-Cell Cars To Ask Toyota, Honda & Hyundai

Meanwhile, Honda is working on its own fuel-cell car, a successor to its FCX Clarity, and a handful of Hyundai Tucson Fuel Cell crossovers are now on the roads of Southern California.

Last month, we published our suggestions for 10 questions that carmakers will inevitably be asked as they launch hydrogen fuel-cell vehicles in the coming years.

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

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

Trade group and all 3 makers

That article, along with yesterday's compilation of their responses to three of those questions, has now generated more than 900 individual comments from our readers--so clearly there's interest in the topic.

ALSO SEE: Hydrogen Fuel-Cell Car Questions: Toyota, Honda & Hyundai Respond (Part 1)

All three carmakers, along with the California Fuel Cell Partnership, responded to our list of questions.

As we noted yesterday, Hyundai had the most detailed response: six single-spaced pages with copious reference links. A substantial portion of its answers underscored the shortcomings of battery-electric vehicles.

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

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

We've summarized the four answers, rather than regurgitating them verbatim, and added our take on the collective responses at the end of each question.

Today, this second article covers two questions we grouped under the heading, "Fueling Infrastructure."

QUESTION 1

What sector of private enterprise now sees a profit-making business in building stations and selling hydrogen as a fuel? What sector of industry will those stations come from? Who will risk the capital to build thousands of hydrogen fueling stations at $1 million to $3 million apiece?

Here, the California Fuel Cell Partnership was the most informative.

"Most current stations are developed by industrial gas companies, including Air Products, Air Liquide, and Linde.

"New companies such as Hydrogen Frontier, First Element Fuel, and Stratos Fuel see a future in building hydrogen stations and selling fuel.

MORE: First Element Expects To Make Money Selling Hydrogen Fuel In 5 Years

"The first 100 stations in California are co-funded by the state through a competitive grant process. We're starting to see some lower costs in the grant requests, particularly with 100-percent renewable stations.

"Economies of scale will continue to lower costs, and the private market should be able to stand on its own as more stations are built and more equipment providers enter the supply chain."

Dozens of companies

Honda noted "dozens of companies engaged in the development of hydrogen infrastructure," and echoed several of the names above.

Honda Solar Hydrogen Station prototype with 2010 Honda FCX Clarity hydrogen fuel-cell vehicle

Honda Solar Hydrogen Station prototype with 2010 Honda FCX Clarity hydrogen fuel-cell vehicle

It also noted that "gasoline refueling station network owners" were among the "entrepreneurs ... investing their own capital."

Toyota echoed the same list as well, noting that private companies were building stations in California, Germany, and Japan.

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

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

Those companies, "along with governments, are providing the capital needed to start the industry." it said.

And, Toyota added, "many studies have shown the viability of retail hydrogen as a business and the opportunity to reduce future station costs," although the company didn't identify specific research.

Public-private partnerships

As it did for other questions, Hyundai provided the longest answer, but in this case it took a different tack from the other respondents.

First 2015 Hyundai Tucson Fuel Cell delivered to lessee at Tustin Hyundai, June 2014

First 2015 Hyundai Tucson Fuel Cell delivered to lessee at Tustin Hyundai, June 2014

Rather than identifying companies, it noted that all new alternative fuels require a combined effort between governments and private partnerships.

"It is widely accepted," Hyundai wrote, "that as vehicle supply increases and consumer fueling needs increase, stations will gradually be able to achieve profitability."

Hyundai ended with three paragraphs and a chart that discussed similar challenges for electric-car charging infrastructure, noting that neither charging nor hydrogen fueling "is exempt from requiring assistance to rapidly expand at this juncture."

The company cited a Green Car Reports article from last year that quoted a utility saying it could not find a scenario under which electric-car drivers would pay Level-2 public charging fees high enough to cover the costs of building and maintaining public charging stations.

(Left unnoted was that many businesses now offer electric-car charging for free, as a marketing lure or customer perk. Those same businesses would be highly unlikely to offer free hydrogen fueling given the six- or seven-figure cost of a hydrogen station versus the four- or five-figure cost of a charging station.)

OUR TAKE: There are clearly startup companies eager to get into the hydrogen fueling business, many of which say they expect to turn a profit in later years. Meanwhile, they are supported by funding from the state of California and hydrogen-car makers.

Honda FCEV Concept, 2013 Los Angeles Auto Show

Honda FCEV Concept, 2013 Los Angeles Auto Show

Whether they will survive and prosper, making it to independent profitability after government support ends, remains to be seen. More than half of all startup companies vanish within five years--as a number of electric car-charging networks have recently learned.

QUESTION 2

A kilowatt-hour of energy will propel an electric car 3 to 4 miles. A kilowatt-hour of energy used to make hydrogen produces perhaps one-third that distance. Why is making hydrogen a good use of energy for transportation?

On the surface, this seemed to us a fairly simple and direct question.

Not an obvious assumption?

It included what we thought was an obvious assumption: We assumed the same carbon intensity for each kilowatt-hour.

Geothermal Power Plant in Iceland

Geothermal Power Plant in Iceland

We asked it largely because some comparisons of wells-to-wheels carbon footprint for hydrogen fuel-cell vehicles and battery-electric cars used different assumptions about the grid mix for one versus the other (see our critique of one such study).

The Fuel Cell Partnership didn't see it quite that way. "The question isn't quite apples to apples," the group responded.

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

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

"To calculate the wells-to-wheels energy use, you have to factor in the energy used to make the electricity."

Indeed. Perhaps we ought to have made our assumption (that the energy used to make the electricity would be identical for both vehicles) clearer.

Total petroleum use

"In terms of total petroleum energy use from wells to wheels, fuel-cell and battery-electric vehicles are about the same," the response continued.

The response also linked to a pair of graphs in a May 2013 Department of Energy study that looked at wells-to-wheels petroleum usage projected for 2035 for mid-size cars and mid-size SUVs, as measured in petroleum BTUs per mile.

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

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

Indeed, the four pathways for battery-electric vehicles and two of the four for hydrogen fuel-cell vehicles were within the same range.

Worthy of note, however, is that one of those two is "natural gas with sequestration"--meaning that the carbon dioxide byproduct of reforming natural gas into hydrogen must somehow be captured and stored, rather than released into the atmosphere.

That's a technology that doesn't yet exist, to the best of our knowledge.

Yes, but...

However, our question wasn't actually about "petroleum usage," but wells-to-wheels carbon footprint--which we also addressed more directly in our subsequent question.

The study cited by the Partnership had two graphs on that topic as well, and the results were rather different. (We'll cover that topic in more detail in the next part of this series.)

Toyota Fuel Cell Sedan at Aspen Ideas Festival [photo: Riccardo Savi]

Toyota Fuel Cell Sedan at Aspen Ideas Festival [photo: Riccardo Savi]

Of the carmakers, Hyundai said, "It is generally understood that battery-electric vehicles are a more efficient pathway for electricity utilization in transportation."

Toyota wasn't willing to go that far, writing that both types of cars are "extremely efficient in their use of energy--as measured by both well-to-tank and tank-to-wheel efficiency."

But, Hyundai suggested, "a more accurate comparison would consider total wells-to-wheels energy efficiency, with more precise results"--and Toyota said much the same, offering two more indicators that our implicit assumption wasn't obvious enough.

Electric-car drawbacks

Hyundai added that "reliance on a single technology" exposed consumers to the "critical shortcomings" of a battery-electric vehicle: limited range, lengthy and inconvenient charging times, and vehicle size limitations.

First 2015 Hyundai Tucson Fuel Cell delivered to lessee at Tustin Hyundai, June 2014

First 2015 Hyundai Tucson Fuel Cell delivered to lessee at Tustin Hyundai, June 2014

And the company went on to say, quite realistically in our view, that very few consumers buy solely on energy efficiency considerations if the most efficient vehicle doesn't meet their needs.

Toyota further wrote that while battery-electric vehicles are more efficient in the "tank to wheel" (or battery to wheel) portion of the cycle, hydrogen fuel-cell vehicles have higher "well to tank" efficiency because "less energy is lost in the production and distribution of hydrogen."

That's an interesting claim, one we'd like to dig into more (Toyota didn't provide citations, but we'll ask for them).

As a results, Toyota concluded, the overall wells-to-wheels efficiencies of the two vehicles are quite close--and "depending on the different assumptions that go into the calculation, either one might be slightly more efficient overall."

Light-duty vehicle type scenario, now-2050 (California Air Resources Board)

Light-duty vehicle type scenario, now-2050 (California Air Resources Board)

Honda said, in effect, that California has a fairly clean grid now, which will become much cleaner yet in the future, and the state believes that both hydrogen and electricity are ultra-low carbon solutions for transportation.

"We agree with that assessment," Honda concluded.

OUR TAKE: While the point that the carbon footprint of generating electricity must be accounted for is entirely correct, we're slightly startled that our question wasn't interpreted to assume identical sources for each kilowatt-hour.

The complex question of overall wells-to-wheels efficiency clearly deserves more study. We'll cover answers to a followup question on that topic in more detail in the next part of this series.

(Our next article will cover the questions we listed under the topic of Energy Balance.)

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