After decades of R&D, some false starts, and a smattering of low-volume production vehicles, hydrogen has emerged as a vital enabler for carbon reduction across the transportation sector. In gaseous form, our lightest and most abundant chemical element is an efficient energy carrier and battery-like storage medium. When produced from decarbonized sources and used in fuel-cell systems, hydrogen can be a genuinely low- or zero-emission source of electricity.
Energy-grid experts increasingly see hydrogen as a valuable “knob to turn,” broadening renewables’ effectiveness by serving as a load-balancer for wind and solar. For vehicle engineers and customers, hydrogen fuel cells — with an energy-to-weight ratio 10X greater than lithium batteries — offer some key practical advantages over battery-electric propulsion. Time required to fill the 350- or 700-bar (5,000- or 10,000 psi) high-pressure storage tanks is as quick as topping up with gasoline or diesel. And compared with the ponderous mass of large-EV battery packs—3,000 lb. (1360 kg) in GM’s Hummer EV and an estimated 10,000 lb (4536 kg) in Tesla’s Class-8 Semi — a fuel-cell propulsion system with similar performance is a veritable lightweight.
Fuel cells’ performance and efficiency are indeed a logical fit in commercial vehicles, according to a dozen industry experts interviewed for this article. The aim is to replace the reliable and durable heavy-duty diesel — admittedly a tough bogey. Daimler, Hyundai, Kenworth (using a Toyota fuel cell stack), Nikola and Volvo have pilot fleets of hydrogen fuel cell Class-8 semitractors in haulage operations. Fuel cell power is beginning to appear in medium-duty truck chassis, buses (where China leads) and on up the GVW scale to huge mining machines, railway locomotives and ships. In the light-duty pickup segment, battery-electric has thus far been the clean-propulsion choice. However, engineers working on those programs at Ford, GM, and Rivian have told SAE Media that their trucks’ all-season range as a function of payload and towing has fallen frustratingly short of IC-engine expectations.
Ford Motor Co. CEO Jim Farley spoke pragmatically about EV limitations — and hydrogen’s benefits — during last fall’s media intro of the 2023 F-250 Super Duty trucks. “If you’re pulling 10,000 pounds, an electric truck is not the right solution,” he asserted. “And 95 percent of our customers tow more than 10,000 pounds. This is a really important segment for our country and it will probably go hydrogen fuel cell before it goes pure electric,” Farley said.
Perhaps not coincidentally, at CES 2023 Patrick Koller, CEO of hydrogen storage tank supplier Forvia, told Reuters that he expects a fuel-cell pickup to be launched in the U.S. by 2025. It’s worth noting that a 10,000-lb. max towing rating is also available in the light-duty F-150 Lightning equipped with the 131-kWh extended-range battery — a $20,000 option.
Highlighting the challenge of electrifying the largest vehicles, propulsion systems and power generators, Dr. Gill Pratt, CEO of the Toyota Research Institute, noted that a typical battery-electric Class-8 truck will need an average of 1 megawatt of power to charge the 1-megawatt-hour battery that powers the truck. “It’s also going to take an hour to charge,” Pratt explained. “At a typical truck stop, for example, for every existing diesel fuel pump that can fill up a truck’s tanks in six minutes, you would need 10 chargers operating at the same time. So, that’s 10 megawatts of power you need to replace one diesel pump. It's just not going to happen. That’s why hydrogen is such a big focus of our attention.”
Last year Toyota and partner Kenworth, using a fleet of Kenworth T680 semitractors powered by Toyota hydrogen fuel cells, demonstrated vehicle range, payload, and fueling times that equaled those of comparable diesel-engined rigs in normal haulage operations. The project was supported by Toyota, PACCAR and Shell, and funded with a $41 million grant awarded by the California Air Resources Board.
Demand, development, investment
Google any combination of “hydrogen, fuel cells, vehicles, automakers, suppliers, and markets” and it yields screens full of news on investments, partnerships and joint ventures, mergers and acquisitions, vehicles, technologies, hydrogen generation, facility expansions and research. “Momentum in terms of investment and development is super strong, and it’s increasing,” observed Dr. Byron McCormick, former executive director of GM’s global fuel-cell program. McCormick is revered at Los Alamos National Laboratory, where as a scientist in the early 1970s he launched the lab’s fuel-cell R&D for vehicles. His work at LANL and GM led to breakthroughs in cathode performance, specific power, cold-weather operability, and overall stack durability that benefit industry engineers today.
A recent report by Boston-based BCC Research forecasts the global market for hydrogen fuel cells for all applications to grow from $7.5 billion in 2022 to $19.5 billion by 2027, at a compound annual growth rate (CAGR) of 21.0% during the period. While development activities are at a higher pace among commercial-vehicle OEMs, a growing number of passenger-vehicle makers (and some who manufacture both) have launched or ramped up their hydrogen work in parallel with their electric-vehicle developments. Some analysts view these strategies as a hedge if EV sales, battery-chemistry advancements, and strategic materials sourcing fall short of 2035 electrification goals.
Honda, for example, is collaborating with GM (which has built prodigious intellectual property in the field over 50 years) on fuel-cell development. Honda will launch U.S. production of hydrogen fuel cell vehicles in 2024; the first model is a plug-in hybrid based on the new CR-V. BMW, which like Honda is following a multi-modal propulsion strategy, is building a pilot fleet of 100 iX5 Hydrogen SUVs. Fuel-cell technology and vehicle development continues with aggressive programs at Toyota and Hyundai, both among the industry leaders. GM itself has created a separate business unit, Hydrotec, that is moving to productionize a range of modular PEM-type fuel cells designed for use across multiple industry sectors including the largest transportation and power-generation uses.
“Electrification and hydrogen fuel cells are very complementary to each other,” observed Charlie Freese, executive director of GM’s Global Fuel Cell organization. “The physics and technologies that go into making a very good battery are actually made better by what I hybridize in a fuel cell application. A good fuel cell makes a battery stronger and vice versa. We can optimize each one around the way they work best. What goes behind making them good for a very big truck also makes them good for the other applications.”
While batteries also serve as energy-recovery tools, Freese asserted that “for working vehicles, there is a very real issue: bigger batteries take longer to charge or demand much higher-powered fast chargers.” And battery mass frequently must be offset by payload reductions. “This is where hydrogen comes in,” he said.
The OEMs’ rekindled interest in hydrogen fuel cells has spurred significant investments (and profound business-model pivots) by suppliers including Bosch, Schaeffler Group, Faurecia/Forvia, Mahle, and Magna, and supplier collaborations (recently ZF with Freudenberg, Forvia with Symbio).
Industry stakeholders aim to leverage federal incentives in Europe and North America. In the U.S., the Inflation Reduction Act of 2022 gives hydrogen production, storage, and utilization multiple tax benefits. The law introduces a 10-year production tax credit (PTC) for “clean hydrogen defined by the lifecycle greenhouse-gas emissions rate achieved at a qualifying hydrogen production facility on which construction starts before 2033.” It extends and creates Investment Tax Credits (ITCs) for clean-energy generation. Producers can opt for either credit type. The IRA defines “clean energy” by a maximum emissions rate of 4 kg of CO2e (carbon dioxide equivalent) per kilogram of hydrogen. It provides a substantial credit for clean commercial vehicles and expands the alternative fuel station credit to help grow the number of hydrogen fueling stations. Under the IRA, the hydrogen must be produced in the U.S.
“Government can help kick-start this, but then investors must see a viable return,” McCormick observed. “Clearly that is occurring.”
H2 in IC engines
While enormous progress in developing fuel cells, vehicle systems, and hydrogen storage and generation solutions has been made and continues, challenges remain – but engineers are confident they can be addressed this decade. Hydrogen as IC engine fuel, substituting (with modifications) for diesel fuel in commercial-vehicle, stationary and marine diesels, is controversial. The concept appeals both to diesel-engine manufacturers and some fleet/equipment operators as an near-term step while electrification issues are sorted out. Hydrogen ICEs have been a focus of various OEMs, notably Daimler (which offered a limited run of H2-fueled passenger cars), Toyota, and Cummins Engine, which is developing its own fuel cells but also sees great promise for hydrogen with its diesel engine platforms.
Fuel-cell pioneer McCormick quickly disregards burning hydrogen in a combustion engine — “they tend to make less specific power and are thus less efficient than diesel,” he told SAE Media. “One reason fuel cells match so well with H2 is that they’re at least 2X more efficient than combustion engines. So they make up in efficiency what they lose in more challenging [fuel] storage.”
Veteran combustion-engineering researcher Dr. David Foster at the University of Wisconsin-Madison, notes “aspects of hydrogen as a fuel that are really great. No carbon. Flame speeds are high. You can go very, very lean with hydrogen, which is good. NOx is reduced, and you may be able to meet NOx emissions without aftertreatment. Going very lean, with lots of boost, you can start to recover some, but not all, of your max load limit.
“Viewing it as a system, there are challenges,” Foster admitted. “The really high energy density that comes with each injection of liquid fuel into a cylinder is very difficult to replicate with hydrogen because you’re injecting a gas.” He noted ongoing work by Mahle, with their jet igniter, that’s trying to overcome the limitations. Hydrogen also causes metal embrittlement “so there are some materials issues to deal with. Not trying to belittle the hurdles, but I classify these as engineering challenges. In the end, there is nothing that’s a stopper for using hydrogen in an IC engine.”
Cost reduction crusade
Engineers working in fuel-cell development who spoke with SAE Media believe most of the technological hurdles of the stack and its chemistries and ancillaries have been overcome. Continuing to prove durability and cost reduction are near-term focuses, as is robust and durable sealing solutions from source to end use: the tiny hydrogen molecules are notorious escapees. The major cost reductions that everyone is working on are a function of industrialization of internal components and hardware. “For a long time a big concern was the cost of platinum [catalyst for the hydrogen and oxygen reactions, determined by the U.S. Dept. of Energy to represent 40% of overall cost at 500,000-unit/year volumes],” noted Pratt at Toyota. “We’ve managed to lower that amount in our latest version and we will keep on doing that with future versions."
In working toward platinum-free catalysts, innovators are looking to reduce the platinum loading per fuel cell. One of them is Pajarito Powder, a manufacturer of fuel cell catalysts and electrolyzers. During a visit to the company’s Albuquerque, New Mexico, facility, company CEO and co-founder Tom Stephenson explained to SAE Media that Pajarito’s quest is to make the diminishing quantities of platinum in each fuel cell more efficient. The black catalyst powder Pajarito developed in a collaboration with LANL and the University of New Mexico (who license the technology to Pajarito Powder) is under evaluation within the fuel-cell industry. Stephenson believes his company’s patented technology will reduce fuel-cell catalyst costs by half. One Pajarito investor, Hyundai, is helping to fund a catalyst manufacturing facility that will use the company’s VariPore process.
Costs also can be mitigated by design-engineering the system for its specific application. “Every electrochemical cell has some resistance to it, so the higher the power draw or current, the greater the resistive losses that occur within the cell,” Pratt explained. “The stack’s efficiency peaks under light power draw and decreases as the power draw further increases. You can use a stack that is bigger, to give higher efficiency. Or you can use a smaller stack, which is lower cost, lower mass, and fits better in the vehicle, but its efficiency will be lower unless the platinum loading is increased. Finally, we can vary durability with different aspects of the design, which affects cost.
Fuel cells offer many “dials to turn” to optimize the system, the experts state. It comes down to the amount you want to spend on initial system purchase, versus its operating cost. To optimize total cost of ownership, “you weigh them against each other,” Pratt said.
Hydrogen is primarily produced by the reforming of conventional hydrocarbons, typically natural gas (the so-called ‘grey’ hydrogen in the accompanying graphic). Electrolysis, a process in which an electric current is run through water to produce streams of hydrogen and oxygen gases, is gaining share in the hydrogen-production market due to its ability to generate the gas carbon-free with renewable energy. McCormick calls the electrolyzers “the way forward” in making fuel cells a truly zero-emission source of electricity, when the hydrogen is produced from decarbonized sources.
“Electrolyzers are inevitable,” said Freese at GM, a 30-year veteran of propulsion-systems technology development. “All the ‘green’ energy like wind and solar on the grid introduces cyclical behavior and irregularities in supply-and-demand that end up causing complexity to the grid that makes it difficult to manage. The only way to manage it may be to overcapacitize the grid for everything, then underutilize the assets you put on the grid. But that’s not economical. You can do that on a transition, but it can’t be sustained long-term to operate an efficient grid.”
What’s needed to balance the grid and run it at optimum levels, Freese asserted, is the ability to store energy for long periods of time — take it off the grid when there isn’t natural demand for it. “Hydrogen is an excellent way to provide that energy storage, if you have electrolyzers to take the energy off the grid on demand.”
Freese noted that the optimum type of electrolyzer for this uses the same PEM-based technology that GM and most others use in their fuel cells, but with the chemical process running in reverse. In 2022 GM and Nel Hydrogen U.S., a subsidiary of Norwegian company Nel ASA, began collaborating on more efficient, lower cost, and scalable electrolyzers that can then be used as a way to do distributed off-take power agreements with the grid. “It will also enable hydrogen to be produced closer to the point of use for fleet refueling and dispensing to retail outlets,” Freese said, noting that transportation is a significant chunk of hydrogen’s cost. Lowering the cost of electrolyzers “is lowering the cost of making the fuel from renewable electrical sources,” emphasized Pratt.
In order for hydrogen and the myriad of fuel-cell applications to be successful, a robust infrastructure for hydrogen generation and distribution is necessary. It’s the same scenario with EVs (including billions in government support), except they are entering the market with a basic electrical grid already in place. Hydrogen by comparison is starting from scratch.
The infrastructure build-out “cannot be done only by the government,” McCormick said. “It must be able to produce an acceptable and timely return on investment.”
Freese and Pratt agree that the key to a ubiquitous and accessible hydrogen-supply network are the synergies being developed from adjacent markets — intermodal rail, marine terminals, truck terminals, airports.
“There is already an economic model for forklift fleets that favors fuel cells, as GM now uses in some of our three-shift plants,” Freese explained, “with the same types of behaviors related to a big commercial vehicle: fast refueling, uptime requirements, low maintenance and the ability to generate power to do work. Once you have the hydrogen in place, what else comes into a plant or warehouse? Trucks. It’s an intramodal-freight node that can share infrastructure. Then the trucks go to the railyard, whose infrastructure can refuel both the trucks and the locomotives. They also go to ports and airports, where the same intramodal fuel sharing can be done. It creates a tailwind for fuel cell adoption once you get to the critical mass out there.”
The nodal strategy to building out the hydrogen infrastructure creates high-volume usage which in turn leads to investment worthiness,” McCormick maintains. He points to investors already creating funds and structuring a hydrogen-supply roll out on major freight corridors. Personal fuel-cell-powered vehicles would come last in this evolution because until sufficient numbers of vehicles are on the road, “the investment doesn’t pay out in a timely manner.”
But the boom in hydrogen investment is also driving other concepts for hydrogen distribution. A new California-based company, Universal Hydrogen, has built a business model around shipping hydrogen like dry freight, using dedicated road trailers, as company CEO and co-founder Paul Eremenko detailed during a recent presentation. “Unless you have a need for it there is no reason to build pipelines,” said Toyota’s Pratt.
Going forward toward 2030, hydrogen and fuel-cell technologies will be an increasingly critical piece of global de-carbonization solutions. “We always worried about whether hydrogen could be coming down to where it’s actually competitive with offsetting the petroleum-based fuels,” commented GM’s Freese. “There are pathways to do that now.”Continue reading »