Is hydrogen power the hero we need to transition to a more sustainable future? Could we replace gasoline-, diesel- and natural gas-powered vehicles with hydrogen? This compressed gas could be an excellent fuel to power long-haul transportation machines, making it a good fit for rural transportation where a string of electric vehicle charging stations may be harder to find.
For hydrogen to be considered more sustainable than other gas fuels, it depends on the “color” we choose.
What are the upsides of hydrogen power? Many years ago, I saw a news story about a compact car powered by hydrogen. The cinematic peak of the news footage was a single drip of water falling to the ground from the tailpipe. A quick Google search reveals many photos of people holding cups under the tailpipe of hydrogen cars.
In 2015, a few Honda dealerships in Australia took this marketing technique a step further. “Honda H2O” looked like a simple, single-use bottle of water. You may be ahead of me here, but the catch was that the water was from the Honda FCX car! Amazing! Here is a video where they stocked a movie theater with Honda H2O.
What are the downsides of hydrogen power? A hydronic heating system in a home may be pressurized to about 15 pounds/square inch (psi). A hydrogen tank in a car may be stored at 5,000 to 10,000 psi. While tank manufacturers can build vessels to handle these pressures, I imagine they wouldn’t want to ride in the first automobile crash test with a hydrogen tank.
The storage pressure alone isn’t a disqualifying factor for consumer-grade automobiles and fuel stations. However, one would be justified in having a bit of concern to sit on top of a 5,000 psi tube while traveling on the highway. To be fair, unless your mode of transportation is a sailboat, the energy required to move a vehicle could be dangerous in rare circumstances.
How do we source hydrogen energy? The National Renewable Energy Laboratory explains the energy procurement process: “Because hydrogen typically does not exist freely in nature and is produced from other sources of energy, it is known as an energy carrier. It is a clean-burning fuel, and when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a byproduct.”
Hydrogen isn’t something we can gather in a mine or out of thin air. “Hydrogen can be made directly from fossil fuels or biomass, or it can be produced by passing electricity through water, breaking the water into its constituent components of hydrogen and oxygen,” NREL notes.
CNBC describes the differences between green and blue hydrogen, two nicknames for the underlying processes to harvest hydrogen through electrolysis: “Green hydrogen is when the energy used to power electrolysis comes from renewable sources [such as] wind, water or solar.”
Similar to charging a lithium-ion battery with solar photovoltaics, green hydrogen has the least carbon emission baggage of the hydrogen processes. However, it isn’t the most cost-effective way to bottle hydrogen.
CNBC continues: “Blue hydrogen is hydrogen produced from natural gas with a process of steam methane reforming, where natural gas is mixed with very hot steam and a catalyst. A chemical reaction occurs, creating hydrogen and carbon monoxide. Water is added to that mixture, turning the carbon monoxide into carbon dioxide and more hydrogen.”
If the carbon dioxide emissions are captured and sequestered forever, resulting in no net emissions, this is considered blue hydrogen.
Is blue hydrogen a concept or a reality? “Hydrogen made from natural gas leads to more fugitive emissions — [methane leaked] into the environment during the extraction and processing of natural gas — compared [to burning] natural gas directly,” notes Fiona Beck in The Washington Post. She co-authored the peer-reviewed paper on clean hydrogen from the Australian National University published in the journal Applied Energy.
She adds: “Including [carbon capture and storage] in the process actually increases fugitive emissions further, as more natural gas is needed to fuel the process.” Similar to “clean coal,” it is only clean if the emissions are captured on an industrial scale.
The next set of hydrogen production colors might be the most cost-competitive, but they are the most like traditional stock-based power production. Grey hydrogen is the product of a natural gas process that doesn’t attempt to capture emissions, so it is a different way to package energy from natural gas. The same goes for brown hydrogen, which is produced with coal power.
Pink hydrogen uses nuclear power. Yellow hydrogen uses electricity from an electrical grid, which could contain a mix of sources to power that grid. Turquoise hydrogen is gathered with pyrolysis, a chemical reaction producing hydrogen and solid carbon.
The average hue of hydrogen is important in the big picture of considering its use as a fuel source. “Most hydrogen production today is by steam reforming natural gas,” NREL explains. “[However,] natural gas is already a good fuel and one that is rapidly becoming scarcer and more expensive. It is also a fossil fuel, so the carbon dioxide released in the reformation process adds to the greenhouse effect.”
While only drinkable droplets of water are coming out of the tailpipe of a hydrogen car, the actual hydrogen fuel production can still burn large quantities of fossil fuels.
Low Market Share
Have any of these hydrogen harvesting methods led to more automobile market share? In 2022, Toyota sold 2,604 Mirai hydrogen cars — the most popular hydrogen car in the United States. For reference, Ford sold that many F-Series trucks in less than 48 hours, averaging its 2022 sales for 365 days.
While the Mirai and F-Series trucks are functionally very different, why haven’t small hydrogen cars become more popular in large urban markets that buy a lot of electric vehicles?
A 2022 Car and Driver article found that California hydrogen prices would be like paying $5 to $8.50 per gallon of gasoline. It also noted that hydrogen fueling stations are not as convenient as gas stations or even electric charging stations. “Today’s stations can often only fuel two to five vehicles before they go offline for up to half an hour to repressurize,” the magazine reports.
Green hydrogen is a potential game changer in the transportation world, but can it become the most cost-competitive color of hydrogen? “In 2020, [green hydrogen] only constitutes 0.1% of global hydrogen production,” data and analytics provider Wood Mackenzie wrote in its Hydrogen Guide. The Intercept found that renewable energy, transported as electricity, was 75 percent less expensive than green hydrogen.
For hydrogen to become viable and sustainable, a moonshot of technology is still required. l
Max Rohr is the education and industry engagement manager with Caleffi North America. After graduating from the University of Utah, he began his manufacturing career at the Caleffi headquarters in Italy. Since then, he worked for several HVAC/P industry companies in the manufacturers’ rep and wholesale distribution channels before returning to Caleffi in 2020. He can be reached at email@example.com and on Instagram @caleffi_na_max.