Countries seeking ways to transport people while reducing the emissions of climate-changing gasses are looking at trains powered by hydrogen fuel cells. One of the first is Germany's Coradia iLint, but countries all over the world are looking at the promise of hydrogen trains as a means of increasing decarbonization. Earlier this year, Alstom said it performed 10 days of tests on its Coradia iLint hydrogen fuel cell train on 65 kilometers of line between Groningen and Leeuwarden in the north of the Netherlands.

“The tests follow 18 successful months of passenger service on the Buxtehude–Bremervörde–Bremerhaven–Cuxhaven line in Germany, where a total of 41 Coradia iLint have already been ordered," the company noted in a press release. The trains are equipped with fuel cells to convert hydrogen and oxygen from air into electricity, and have a range of approximately 1,000 kilometers, according to Alstom. In addition, the battery on the train can recover energy during braking, which it can then use to boost the train when it's accelerating.

Trains are particularly well-suited as a means of developing carbon-free transportation, although researchers are looking at hydrogen as a means of decarbonizing a number of transportation methods, according to Raphael Isaac, senior transportation data analyst for Energetics, a Columbia, Maryland-based energy consulting firm. Previously, he was a technical researcher on fuel alternatives in rail for Michigan State University, in East Lansing, Michigan. “You have a lot of space on the train," Isaac says. “The constraints you might have otherwise are not as big of an issue."

Urban regions have been electrifying their trains for some time to help decarbonize them, notes Isaac, but that process can be expensive, especially in rural areas. According to the BBC, electrifying a single kilometer of track can cost £750,000 to £1m ($965,000 to $1.3m). Hydrogen doesn't require adding a costly electric infrastructure, but allows trains to run on the existing rail infrastructure. According to the BBC, electrifying a single kilometer of track can cost £750,000 to £1m ($965,000 to $1.3m). Hydrogen doesn't require adding a costly electric infrastructure, but allows trains to run on the existing rail infrastructure. “Hydrogen is clean and quiet like electricity, but it doesn't have the high cost," Isaac says.

Consequently, any location that doesn't already have electric train infrastructure, such as many areas of the U.S. and Europe, are potential use cases for hydrogen trains, Isaac explains. Another advantage of converting to hydrogen to power trains is that rail technology is often centralized within a region, which can simplify the decision-making process more so than for other transportation methods. “With rail, you don't have 300 million decision-makers," as with automobiles, Isaac points out. Coordinating that switch would be easier than with cars, but technologies in the rail industry change slowly, he admits.

Isaac acknowledges that hydrogen-powered trains do have some disadvantages. Most notably, because hydrogen is a gas, it takes up a lot of space relative to the energy it provides, he says. “There's more space in rail than in a car, but hydrogen has a low energy per volume because it's such a light gas," he says. “You get a lot of energy per mass, but not as much as volume." Trains also use more energy than cars because they're bigger, but that also means they potentially have more space to hold the hydrogen, he notes. And while hydrogen gas can be compressed, that requires additional energy. The cost of hydrogen production is another factor. Although it is the most abundant element in the universe, it is typically tied up in other substances, Isaac says. “Hydrogen does not 'exist naturally,'" he explains. “You have to extract it out of water or natural gas." 

Environmental concerns are another factor. First of all, hydrogen can be made from either natural gas —blue hydrogen— or from water —green hydrogen, according to Greentech Media. Making hydrogen from water can be environmentally cleaner than making it from natural gas, as hydrogen electrolysis uses electricity to break down the components, Isaac explains. It also doesn't require the use of carbon-based natural gas, which is largely methane. Mining natural gas also has environmental impacts. However, the cleanliness of the green hydrogen process is predicated on the cleanliness of the electric grid used to produce it —if the electrical power is produced from renewable sources such as hydropower, wind, or solar, for example. “If the grid isn't clean, it won't be as good a method," Isaac points out.

Alstom's efforts in Germany and Netherlands aren't the only ones. Other countries that are testing hydrogen trains or considering testing them in the future include Austria, Scotland and other parts of the United Kingdom, Denmark, Norway, Italy, Canada, France, the U.S. and Spain. For example, the U.K. has also been testing hydrogen-powered trains —which it calls Hydroflex— since 2019 as part of its plan to eliminate diesel trains by 2040, according to the BBC. “The fuel cell is made up of an anode, a cathode and an electrolyte membrane," cites the BBC article, Next stop, hydrogen-powered trains. 

“The stored hydrogen passes through the anode, where it is split into electrons and protons. The electrons are then forced through a circuit that generates an electric charge that can be stored in lithium batteries or sent directly to the train's electric motor." Similarly, Scotland's University of St. Andrews took steps in September 2020 to begin a 12-month project to convert a three-car train to hydrogen as part of its Zero Emission Train Project. The university is working with Scottish Enterprise, Transport Scotland, Brodie Engineering and Arcola Energy and hopes to demonstrate the technology at the United Nations Climate Change Conference (COP 26) in December 2021.

Scotland's train decarbonization goal currently the most ambitious in Britain; the Scottish government hopes to decarbonize their passenger rail transport by 2035. Converting railways to low-carbon hydrogen may not have an immediate effect on world decarbonization efforts as other forms of transportation are more prevalent, Isaac admits. “Rail may be 1-2% of all transmission emission in the U.S." But switching trains to hydrogen may help foster advances in technology and an increase of overall hydrogen production. “It's playing a role in allowing and enabling that technology to thrive."

Is the Managing Editor at Idaho Business Review and former writer at The Economist. Previously she worked with Gartner Inc. as research director and for the U.S. Forest Service in Biological Research.