The nation's largest contributor of greenhouse gases, transportation, is on a path to reduce its carbon emissions, and electric vehicles (EVs) are leading the way. But EV technology does not have a monopoly on change.
Enter hydrogen. As the most abundant element in the universe, and the third most common element on Earth, it holds tremendous potential as a clean-burning alternative to fossil fuels.
The idea of hydrogen cars is not new. The concept has been discussed and tested for decades. While still mostly on the sidelines, the technology may now be ready to join the great race against global warming and help vehicle travel further reduce its emissions.
Hydrogen Fuel Cells
Hydrogen can be used to power vehicles in more than one way. The most common is with a device known as a hydrogen fuel cell.
Fuel cell electric vehicles (FCEVs) generate power through a process that is not unlike the way a battery works in an electric car. Electrical energy is discharged, harnessed, and transmitted via an electrical motor to produce wheel rotation, which propels the vehicle.
Unlike a battery, however, a fuel cell converts the chemical energy of hydrogen to generate electrical energy. As long as the fuel (hydrogen) is present, the fuel cell can continue to function.
In a fuel cell vehicle, compressed hydrogen gas is stored in a tank, similar to gasoline in a conventional vehicle. But instead of running through a combustion engine, the hydrogen is fed into a fuel cell stack, which is an aggregate of cells where the electro-chemical conversion takes place (see Figure 1).
Each cell contains a positive and negative electrode, which are wrapped around an electrolyte. The hydrogen gas is channeled through the negative electrode, the anode. Meanwhile, oxygen is fed to the positive electrode, also known as the cathode.
A catalyst at the anode splits the hydrogen molecules into electrons and protons. The electrons then travel through a separate circuit, which creates a flow of electricity that is harnessed to power the vehicle’s electric motor (see Figure 2).
At the same time, the protons travel separately through the electrolyte to reach the cathode where they reunite with the oxygen and the same electrons they were separated from.
Fuel cells are efficient, quiet, and clean; there is no combustion, there are no toxic emissions.
Fuel cells are efficient, quiet, and clean; there is no combustion, there are no toxic emissions. The only thing that comes out of the tailpipe of a fuel cell-powered vehicle is water, one of the most innocuous substances on the planet.
The benign impact of a fuel cell is one of its greatest selling points. If society is able to effectively harness the gas, it will have a virtually limitless supply of clean fuel.
Hydrogen Combustion Engines
Not surprisingly, hydrogen fuel cells aren't the only type of vehicle engine powered by hydrogen.
The gas can also be burned in an internal combustion engine (ICE), just like petroleum gasoline, diesel, and ethanol. Like fuel cells, the hydrogen ICE is gaining traction, and more companies are looking closely at the idea. If a hydrogen-powered internal combustion engine could be commercialized, it could solve the problem of emissions generated by the burning of fossil fuels without losing the power and efficiency of an ICE.
Attention has focused on the use of hydrogen ICEs for medium- and heavy-duty vehicles—including vans, buses, and trucks—because ICEs are more efficient than fuel cell engines for vehicles that carry heavy loads over long distances.
The concept is still very much in the development phase, but industry stakeholders are taking it seriously. Attention has focused on the use of hydrogen ICEs for medium- and heavy-duty vehicles—including vans, buses, and trucks—because ICEs are more efficient than fuel cell engines for vehicles that carry heavy loads over long distances. Hydrogen would provide these types of vehicles with the fuel density they need but without the pollutants.
Earlier this year, the US Department of Energy (DOE) announced $10.5 million in funding awards for three projects focused on research, development, and demonstration in this area. PACCAR Inc., an American truck designer and manufacturer, Cummins Inc., an American engine manufacturer, and MAHLE Powertrain, an American company that provides engineering and consulting on hybridized ICEs, were awarded funding. Together, these three ICE projects will support the use of hydrogen in the medium- and heavy-duty transportation sector.
Navigating California's Hydrogen Highway
Developing the proper engine technology is only part of the challenge to a future with hydrogen vehicles. A robust and reliable infrastructure for making hydrogen fuel available is also essential.
Given how the nation's charging network for electric cars is lagging behind, hydrogen fueling stations face a similar problem. The marketplace is not always efficient enough in the early stages to encourage growth of new technologies. Therefore, government plays an important role.
Much like it has been with EVs and solar power, the state of California has been a national leader in advancing hydrogen power.
Much like it has been with EVs and solar power, the state of California has been a national leader in advancing hydrogen power, and, in that respect, also forward-thinking. It took steps to create a refueling infrastructure to support hydrogen cars more than 20 years ago.
Then-Governor Arnold Schwarzenegger waved the checkered flag on the race for hydrogen in April 2004 when he signed Executive Order S-07-04. It initiated the so-called “California Hydrogen Highway Network (CaH2Net),” whose mission was to assure that hydrogen fueling stations were in place to meet future demand created by hydrogen fuel cell electric vehicles entering California roads.
The CaH2Net marked the beginning of a process to coordinate between the California government, academia, and private industry stakeholders to establish a shared vision and create a blueprint of actions needed to create a hydrogen highway in the Golden State.
Nearly 10 years later, California passed Assembly Bill 8 (AB 8; Perea, Chapter 401, Statutes of 2013), which among other things, dedicated up to $20 million per year for 10 years to support continued construction of at least 100 hydrogen fuel stations.
According to the latest annual report on the progress toward meeting the goals set by AB 8, “California’s hydrogen fueling network has grown to 65 stations, with 59 Open-Retail stations available for customer fueling as of August 10, 2023.” Most of those stations are in the highly populated areas of San Francisco and Los Angeles.
[There is] a correlation between the delay in fueling station buildout and a similar delay in market projections for the sale of hydrogen fuel cell vehicles.
A number of factors are cited for the delay in reaching the state's goal of 100 stations. The report does note a correlation between the delay in fueling station buildout and a similar delay in market projections for the sale of hydrogen fuel cell vehicles.
Although the state has not reached its goal, it is still on the way and not far off. The report projects the state could still have 100 fueling stations by as early as 2025.
Hydrogen Vehicles Around the World
California is not the only benchmark. According to market research firm, Interact Analysis, in the first half of this year, 41 countries and regions around the world had operating hydrogen refueling stations (HRSs). Another seven countries were planning or constructing their very first stations.
The distribution of hydrogen stations around the globe is highly concentrated. “China, South Korea, Japan, and Germany have more than 100 operating stations, together accounting for 72% of the global total,” the report said. According to the same data, California accounts for more than 75% of the total in the United States.
A closer look at the world's leader, China, suggests what it might take for hydrogen to catch on elsewhere. Interact Analysis reports that the expansion of HFEVs and HRSs in China is the result of government promotion that has triggered a cycle of expansion.
The promotion of hydrogen and hydrogen vehicles became an official Chinese government policy starting in 2019. It was reiterated in subsequent years leading to growth in the industry and demand for refueling stations.
This increase in demand encouraged 30 provinces and municipal cities across China to issue policies covering the development of HRSs, totaling more than 1,200 sites.
While the United States is not a one-party state, government can still play a role, and the US has taken steps to encourage the development of the hydrogen industry. Last year, the Biden Administration announced an award of $7 billion from the Bipartisan Infrastructure Law to seven “regional clean hydrogen hubs.”
[S]even projects, scattered across the country, will produce, deliver, and provide end-use of clean hydrogen, derived from diverse domestic resources like solar energy, wind, nuclear energy, biomass, and natural gas with carbon capture.
The seven projects, scattered across the country, will produce, deliver, and provide end-use of clean hydrogen, derived from diverse domestic resources like solar energy, wind, nuclear energy, biomass, and natural gas with carbon capture. The administration expects the hubs to “catalyze multistate hydrogen ecosystems,” which will expand and connect to form “a national hydrogen economy.”
HFCEVs on the Road
Many manufacturers have entered the race to build hydrogen fuel cell EVs. According to the national Hydrogen Fuel Cell Partnership, a non-profit collaboration of manufacturers, organizations, government agencies, and other stakeholders, over 18,000 FCEVs have been sold or leased in the U.S. as of September 2024.
Models include the Toyota Mirai, Hyundai Nexo, Honda Clarity, Audi H-Tron Quattro, Chevrolet Colorado ZH2, Mercedes-Benz GLC F-Cell, and Nissan X-Trail. AC Transit and Sunline Transit also each manufacture their own line of hydrogen fuel cell transit buses.
Currently, in the United States, only two models are available to the public. The Toyota Mirai is a sedan that starts at about $50,000. The Hyundai Nexo is an SUV that starts at around $60,000. To ease the pain of refueling, both manufacturers offer a $6,000 credit for the purchase of hydrogen that lasts up to six years on a purchase and three years on a lease.
One final consideration is safety. Hydrogen is an extremely flammable gas. This poses a danger for vehicles that have been involved in an accident. It's important to note that traditional petroleum gasoline is also flammable. But manufacturers have developed designs and rigorous testing methods to make vehicles safe by guarding against the possibility of an explosion after a collision.
HFCEV manufacturers have taken similar measures. Toyota has addressed safety in the Mirai through the design of the fuel cell tank and the refueling nozzle, and rigorous testing of both. Hydrogen is as safe as any other fuel used in a car, proponents say.
Hydrogen may even have an advantage over petroleum gas because it is so light. In the event of a tank leak after a collision, the gas is likely to quickly dissipate into the atmosphere, unlike petroleum gas, which will dissipate much more slowly, increasing the time and likelihood that it could ignite from a spark.
The Future of FCEVs
While still a long way from competing with traditional vehicles, and not even close to its chief rival, EVs, hydrogen vehicles have a promising future.
Multiple studies project strong growth in the years ahead, with total market value growing from around $1 billion to about $40 billion by the end of this decade.
Like so many other new technologies, the prospect for growth presents a quandary. Consumers are not likely to invest in a new vehicle until the refueling infrastructure is available, but the same infrastructure is not likely to be built out until there is enough demand from vehicle owners.
The solution is investment. Judging from the actions of private and public stakeholders, the intent is there. It should only be a matter of time before their actions will pay off.
*Rick Laezman is a freelance writer in Los Angeles, California. He has a passion for energy efficiency and innovation. He has been covering renewable power and other related subjects for more than ten years.
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