Hydrogen Well-to-Wheels Analysis

Business, Hydrogen, Policy  /   /  By Jim Motavalli

As any energy analyst will tell you, hydrogen is not in and of itself a fuel. Instead, it’s best seen as an “energy carrier,” and has to be extracted from something else—notably natural gas (through steam methane reforming) or water (through electrolysis).

The cost of producing hydrogen—which could be compared to the refining process for gasoline—is just one factor in comparing it to more conventional sources of energy. There’s no question that hydrogen could play a role in the energy economy of the future. It’s both the lightest and most available element, and when used in a fuel cell produces zero emission electricity. Fuel-cell development has been impressive, producing ever-larger amounts of power from smaller and smaller stacks.

Today, 95 percent of hydrogen is produced from very affordable natural gas. Advances have been made in electrolyzer technology, but it’s still a significantly more expensive process than methane reforming. According to a National Renewable Energy Lab (NREL) study, on-site natural gas reformation could lead to a cost of $8 to $10 per kilogram (with roughly the energy content of a gallon of gasoline) and $10 to $13 for on-site electrolysis.

More encouraging is this from the NREL study, “Two external independent review panels commissioned by DOE concluded that distributed natural gas reformation could lead to a cost range of $2.75 to $3.50 per kilogram and distributed electrolysis could lead to $4.90 to $5.70 per kilogram.”

But how does hydrogen stack up for vehicle use on a well-to wheels basis? Is it a savior solution for the car of the future, as popular scientist Dr. Michio Kaku has said? Plenty of analysts agree it is.

Jeremy Rifkin, author of The Hydrogen Economy, says, “Hydrogen has the potential to end the world’s reliance on imported oil and help diffuse the dangerous geopolitical game being played out between Muslim militants and Western nations. It will dramatically cut down on carbon dioxide emissions and mitigate the effects of global warming. And because hydrogen is so plentiful and exists everywhere on earth, every human being could be ‘empowered,’ making it the first truly democratic energy regime in history.”

Dr. Michio Kaku extols the virtues of fuel-cell cars with the Toyota Mirai sharing the stage. (Jim Motavalli photo)

Dr. Michio Kaku extols the virtues of fuel-cell cars with the Toyota Mirai sharing the stage. (Jim Motavalli photo)

Kaku says the same thing slightly differently. He told an audience at the 2015 Consumer Electronics Show, “We’re leaving the age of hydrocarbons and entering the age of hydrogen to create a hydrogen non-polluting society.”

That’s the big picture. But there’s good news on the ground, too. According to the California Fuel Cells Partnership (CFCP) in its own “Well to Wheels” report, “Hydrogen made from natural gas and used in a fuel cell vehicle reduces greenhouse gases (GHGs) by 55 percent to 65 percent compared to gasoline used in a conventional vehicle, and by about 40 percent compared to gasoline in a hybrid engine.”

Fuel cells, CFCP says, “are two to three times more efficient than gasoline engines and about twice as efficient as gasoline hybrids.” That’s echoed by the Energy Information Administration, which reports, “On an equivalent basis, electric vehicles with fuel cells powered by hydrogen can double the fuel economy of a similarly sized gasoline vehicle.” That’s why fuel-cell advocates cite efficiency as a reason that $8 a gallon equivalent hydrogen is really like $4 a gallon hydrogen.

mercedes f-cell

The Mercedes F-Cell is helping build a market for fuel cells. (Mercedes photo)

Hyundai cites 2013 studies on well-to-wheel GHGs by the Advanced Power and Energy Program at the University of California, Irvine, to conclude that “hydrogen-powered fuel cell vehicles have the lowest overall emission levels of all alternative fuel entries. Well-to-wheel emissions for hydrogen vehicles sourced from natural gas are lower than battery electric vehicles, and less than half of equivalent gasoline vehicle emissions. Even more impressive, hydrogen emissions sourced from biogas are a tiny fraction of equivalent gasoline vehicle emissions, yielding an extremely high factor of long-range emissions sustainability.”

The UC Irvine report says:

For fuel-cell electric vehicles (FCEVs), hydrogen production does not have to occur at the same time as vehicle fueling due to inherent hydrogen storage capability in the associated production and distribution infrastructure. Therefore, the electric load profile of hydrogen electrolysis can be more easily shaped to capture variable renewable generation at the expense of requiring more input energy….The FCEV pathway [using renewable energy] has lower energy efficiency and require smore infrastructure construction, but may require little to no electric energy storage to realize emissions benefits in the real-world system.

The Not-So-Loyal Opposition

There are dissenters from this rosy view of the hydrogen equation. Ford, which has conducted extensive fuel-cell testing (but is not currently concentrating on the technology), concludes, “Currently, the most state-of-the-art procedure is a distributed [on-site] natural gas steam reforming process. However, when fuel-cell vehicles are run on hydrogen reformed from natural gas using this process, they do not provide significant environmental benefits on a well-to-wheels basis (due to GHG emissions from the natural gas reformation process).”

A major critic is Joseph Romm, author of The Hype About Hydrogen, who proclaims in a Scientific American piece written with plug-in hybrid advocate Andy Frank:

Any effective hydrogen economy would require an infrastructure that could use zero-carbon power to electrolyze water into hydrogen, convey this highly diffuse gas long distances, and pump it at high pressure into the car—all for the purpose of converting the hydrogen back to electricity in a fuel cell to drive electric motor.

The entire process of electrolysis, transportation, pumping and fuel-cell conversion would leave only about 20 to 25 percent of the original zero-carbon electricity to drive the motor. In a plug-in hybrid, the process of electricity transmission, charging an onboard battery and discharging the battery would leave 75 to 80 percent of the original electricity to drive the motor. Thus, a plug-in should be able to travel three to four times farther on a kilowatt-hour of renewable electricity than a hydrogen fuel-cell vehicle could.

Julian Cox of CleanTechnica has also published a lengthy takedown of the hydrogen equation. He writes, after reviewing some of the positive conclusions, “There are no such environmental benefits attributable to hydrogen either now or in any foreseeable future economic reality. On the contrary, hydrogen is a gross threat to efforts to tackle emissions as a result of public policies based on a false environmental premise and by grossly misleading advertising combined with incentives targeting consumers most at risk of deception by messaging citing the alleviation of environmental concerns as a value proposition.”

**

These radically different bottom lines are hard to reconcile. This much we know: The modern fuel-cell car can travel approximately 300 miles on a tank of hydrogen, and fill up in five to eight minutes—two factors that boost its appeal over battery electrics.

If the hydrogen infrastructure is stillborn, the well-to-wheels analysis becomes academic. But automakers and others are investing seriously in expanding it and the “forever fuel” is closer than it’s ever been before.

Comment with Facebook

comments

Leave a Reply