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Are hydrogen fuel cells competitive with battery electric technology?
Posted on August 05, 2018 by Charles Morris
Tesla founders Martin Eberhard and Marc Tarpenning considered many different alternatives to gasoline and diesel before deciding that batteries were the best choice. JB Straubel explained the technical superiority of batteries during a 2016 panel discussion. And as you’d expect, Elon Musk has been quite vocal about the issue, repeatedly describing the shortcomings of what he calls “fool cells.”
Above: Comparing the simplicity of electric cars with the complexity of hydrogen cars (Image: InsideEVs)
We previously published a lengthy discussion of the hydrogen vs batteries debate, with links to arguments on both sides, so we’ll resist the temptation to repeat the list of objections to fuel cells here. Whatever the technical merits of fuel cell vehicles (FCVs) may be, three Asian automakers - Toyota, Honda and Hyundai - have brought them into production. The first and most successful of these is Toyota’s Mirai, which has sold around 6,000 units globally since its 2014 launch.
“We’re going to shift from limited production to mass production, reduce the amount of expensive materials like platinum used in FCV components, and make the system more compact and powerful,” Yoshikazu Tanaka, Chief Engineer of the Mirai, told Reuters.
Now Reuters reports (via InsideEVs) that Toyota is planning a new generation of the Mirai (expected in the early 2020s), and also plans to expand its fuel cell offerings to additional models, including SUVs, pick-ups, commercial trucks and buses and trucks, and to increase production to build economies of scale.
The Mirai’s fuel cell and hydrogen storage systems currently use substantial amounts of expensive materials such as platinum, titanium and carbon fiber. Engineers have been successful in reducing the use of platinum, which serves as a catalyst in the 370 layered cells in the fuel cell stack. “We’ve been able to decrease the platinum loading by 10 percent to 20 percent and deliver the same performance,” said Eri Ichikawa, a fuel cell engineer at Toyota subsidiary Cataler.
The automaker has already developed FCV prototypes of small delivery vehicles and large transport trucks, based on existing vehicles. It’s currently testing fuel cells in Kenworth freight trucks in California, and Sora FC buses in Japan. A delivery truck pilot in Japan is to begin next year.
“We’re going to use as many parts from existing passenger cars and other models as possible in fuel cell trucks,” said Toyota’s Ikuo Ota. “Otherwise, we won’t see the benefits of mass production.”
Most industry observers seem to foresee an uphill battle (to be fair, the same was true when Toyota introduced the Prius in 1997). LMC Automotive predicts that FCVs will make up only 0.2 percent of global passenger car sales in 2027, compared with 11.7 percent for battery EVs. The International Energy Agency also predicts lower numbers of FCVs than plug-in vehicles through 2040.
However, according to Reuters’ sources, Toyota believes demand will grow as more countries, including China, become familiar with fuel cell technology. The company also sees FCVs as an insurance policy against a possible shortage of scarce battery materials such as cobalt.
“It will be difficult for Toyota to lower FCV production costs if it only produces the Mirai,” said Reuters’ unnamed source. “By using the FCV system in larger models, it is looking to lower costs by mass-producing and using common parts across vehicle classes.”
At the moment, Toyota is assembling Mirais by hand, a process that allows only 6.5 cars per day to be produced. The consulting firm Strategic Analysis estimates that it costs Toyota about $11,000 to produce each fuel cell stack (like the battery in a BEV, this is by far the vehicle’s most expensive part). If annual sales grow from today’s 3,000 units to 30,000 units by 2020, as Toyota predicts, that should allow the company to reduce costs to about $8,000 per stack.
Above: An inside look at hydrogen fuel cells (Youtube: Real Engineering)
Meanwhile, a temporary shortage in California has highlighted the challenges of building a hydrogen infrastructure. There are now some 33 hydrogen fueling stations around Los Angeles and San Francisco. Green Car Reports tells us that the hydrogen pumps around LA recently ran out. At one station in mid-July, drivers found a sign reading, “Be advised: Hydrogen delivery issues everywhere. Don’t take chances, top off frequently. Toyota hotline says dealers know, will comp you for rental car.”
Toyota told Green Car Reports that it has traced the problem to hydrogen provider Air Products, which “hopes to have restored regular hydrogen supply in the early days of August.”
“While the station operator works to resolve this short-term issue, we are working with our Mirai customers to help identify alternative fueling options, including as a temporary measure, opening our commercial hydrogen fueling station at the Port of Long Beach,” Toyota told GCR.
A new video from Real Engineering explains the process of producing and delivering hydrogen in a technical but easy-to-understand format.
In the US, most hydrogen is produced from methane using a technology called steam reforming. The process is extremely inefficient, and produces air pollution. Considering that it also uses fossil fuel as a feedstock, producing hydrogen in this way more than negates the environmental benefits of FCVs.
A much greener (though even less efficient) method is electrolysis, which uses an electric current to separate hydrogen from water. Traditional electrolysis has an efficiency of around 70%, whereas a newer technology called proton exchange membrane electrolysis can reach 80%. By contrast, batteries have a charging efficiency of around 99%.
The transport and storage of hydrogen costs about 13% of the energy in the best-case scenario. By contrast, BEVs only have to contend with grid losses, which average around 5% in the US.
Once it’s in the vehicle, hydrogen has an efficiency of around 60% - much better than the dismal 20% efficiency of a gas or diesel engine, but lower than the 75% for a BEV.
So FCVs are less efficient than BEVs at every stage of the process: generating hydrogen; transportation and storage; and converting it back to energy in the vehicle. Considering all these steps together, in the best-case scenario, hydrogen is about half as efficient as battery technology. However, comparing the real-world costs of fuel, Real Engineering found that driving a Tesla Model 3 costs between 2 and 2.4 cents per kilometer, whereas the hydrogen to power a Toyota Mirai costs 17.7 cents per kilometer.
The relative inefficiency of hydrogen as an energy storage medium was enough to dismiss it as a viable solution for Tesla’s founders (and for most other EV-makers). However, in the real world of business and government, decisions are seldom made on scientific grounds. Automakers have convinced government policy-makers to support hydrogen vehicles by touting their advantages to the consumer - longer range and faster refueling times. However, these advantages will eventually disappear as battery technology improves, and with a variety of new 200-mile EVs, and 350 kW DC fast charging, in the pipeline, they’re already dwindling.
Above: Range and charging speeds are all improving — especially at companies like Tesla (Image: InsideEVs)
The advantages of hydrogen to Big Auto and Big Oil are the real reasons why the technology is likely to be with us for some time. Simply replacing gasoline with hydrogen would keep motorists tethered to a corporate-controlled network of fuel stations, and keep the existing top-down, centrally controlled energy system in place. And, while electrolysis powered by renewable energy is the greenest way to store energy in hydrogen, the easiest and cheapest way to do so is to make it from natural gas - and that’s music to the ears of the fossil fuel industry.
Written by: Charles Morris