A decade and a half ago, low gasoline prices and rebounding car sales did nothing to stop Toyota from introducing its fuel-saving Prius hybrid-electric vehicle. During those years the Prius, whose name means “to go before,” pioneered an entirely new green-car category while it burnished the company’s environmental credentials. Hybrid-electric propulsion has now gone fully mainstream, with total U.S. sales of hybrids topping 3 million in late 2013.
Today, with fuel prices sagging and auto sales rising, the Japanese carmaker is again attempting to open up a whole new green-car segment with its first hydrogen fuel-cell production vehicle, the Mirai. Whether the Mirai, which means “future” in Japanese, presages Prius-like success is hotly debated.
'Like any other car'
“The Mirai is like any other car,” Takeshi Uchiyamada, Toyota’s Chairman of the Board and “father of the Prius,” told the press who had assembled Nov. 16 in Newport Beach, CA, at a lead-in event for the Los Angeles Auto Show. “It has a 300-mile range, fills up in 5 minutes and accelerates from 0 to 60 mph in about 9 seconds,” he said. “The big difference is that this car uses no gasoline and emits only water vapor from the tailpipe.”
In the U.S., the four-door Mirai sedan will have a sticker price of $57,500. But with about $13,000 in federal and California state incentives and subsidies, that figure drops to $45,500. Toyota expects the majority of customers to lease the car for $499 per month for 36 months, however.
The initial production goals for the Mirai will be 700 units, according to the company. The car will be introduced into the Japanese market before year’s end and will go on sale in Europe early next year. California dealerships will get the new car by summer 2015 and those in five northeastern U.S. states will receive the first shipments in 2016.
The Mirai, which is the production version of the FCV Concept that was unveiled at last year’s Tokyo Motor Show, is built around a 114-kW fuel-cell stack that converts compressed hydrogen gas into electricity. That electricity is stored in a nickel-metal-hydride battery pack that powers electric motors, which drive the front wheels.
The car’s proton-exchange-membrane fuel-cell stack, which is encased in a protective carbon-fiber composite housing, has a power density of 3.1 kW/L. Unlike many previous units, it requires no humidifier to keep the polymer membranes damp to promote proton transport. Instead, the system circulates the water that the stack itself produces. The compressor and blower whirs and whines that have accompanied most earlier fuel-cell systems have been mostly eliminated to help keep the passenger cabin quiet.
The Mirai contains a pair of 10,000-psi hydrogen storage tanks, one under the rear seats and another just behind them. The tanks, which have 62.4-L (16.5 gal) and 60-L (15.9 gal) capacities, respectively, feature outer protective shells composed of filament-wound fiber/resin composites that are lined with impermeable membranes.
“Why hydrogen?” Uchiyamada asked the crowd rhetorically. The rate of cost reduction for fuel-cell systems is falling faster than that of electrochemical batteries, he answered, noting that “a 300-mile battery would be much larger and heavier than a fuel-cell stack and fuel tanks. Our fuel-cell system is really just a better battery.”
Uchiyamada added that the fuel-cell tanks contain enough hydrogen to power an average American home for a week in emergencies, should buyers choose to add an optional power take-off port.
At 1850 kg (4100 lb), the car is still 100 to 150 kg (220 to 330 lb) lighter than a Camry hybrid, said Satoshi Ogiso, Managing Officer at Toyota and lead on the product planning group for the Mirai. Engineers placed all the fuel-cell system components low in the frame to create a low center of gravity for good handling performance. The underbody of the car is completely covered to cut road noise and aerodynamic drag because the fuel cell’s heat output is less than that of a traditional car engine.
The Mirai’s powertrain is 95% cheaper to build than the fuel-cell system in the 2008 Highlander fuel-cell SUV, he said. Some of cost savings derive from the decision to adopt much of its drive system—controls, energy management system, and batteries—from the company’s hybrid models. Beyond the use of common parts, a brand-new converter triples the system voltage, which saves space, weight, and cost. Other savings stem from minimizing the use of high-priced platinum-family catalysts in the stack, said Ogiso, who added that R&D work is continuing to develop less costly catalyst alternatives.
He explained that the Toyota fuel-cell system is fully scalable and that company planners are contemplating hydrogen-fuel vehicles ranging in size from forklifts to sports cars to trucks and buses.
Ogiso stated that the car’s exterior was styled to be both “distinctive” and “futuristic,” with a feeling of flowing water. Whether Toyota’s design effort was successful depends upon one’s taste, but it must said that the car has something of the look of a Cylon Centurion from “Battlestar Galactica” from the front. The huge air intake grilles are there not only help cool the fuel-cell system’s three radiators, but feed the vehicle’s air-management system. The rear end reminds many of the back of 1970s-vintage BMWs. Whatever the styling, the new Mirai has a slippery aerodynamic drag coefficient of 0.293.
Building a fueling infrastructure
Although the company president and CEO Akio Toyoda in a video touted the Mirai as “a turning point in automotive history” that would cut dependence on oil and environmental degradation, fuel-cell vehicles face an impediment that hybrids do not: a dearth of hydrogen fueling stations and the costly supply infrastructure to support them. This classic 'chicken-and-egg" dilemma accounts for much of the skepticism now aimed at the technology.
Opposition to the adoption of hydrogen as a fuel has arisen in the U.S. because much of today’s hydrogen is made by steam reforming natural gas, which undermines its positive environmental impact. Tesla chief Elon Musk has, for example, called fuel cells “a load of rubbish.”
To help address the fundamental fueling issue, Toyota is partnering with Air Liquide, a global producer of hydrogen and other industrial gases, to develop new regional markets, said Chris Hostetter, Group Vice President for Strategic Planning. Part of the initial plan is to install a dozen hydrogen stations across Connecticut, Massachusetts, New Jersey, New York, and Rhode Island by 2016. Using the Street, a computer model developed at the University of California - Irvine that estimates the number of hydrogen stations needed to supply a fuel-cell fleet, planners have selected strategic locations to create a “hydrogen highway” between the New York and Boston metropolitan areas, said Ole Hofelmann, CEO of Air Liquide.
Hofelmann said that the hydrogen should sell for around $10/kg—energy-wise, a kilogram of hydrogen is roughly equivalent to a gallon of gasoline. Because fuel-cell powerplants offer double the energy efficiency of conventional car engines, $10/kg translates into an effective price of about $5/kg, which would be more competitive with conventional fuels.
Toyota already has invested in hydrogen fueling infrastructure in California, which hopes to set up a hydrogen highway along the West Coast all the way up to British Columbia. UC Irvine’s Street model, which keeps potential customers at all locations within 6 min of a station, indicates that only 65 stations can support some 10,000 fuel-cell vehicles in California. In May, Toyota announced a $7.3 million loan to FirstElement Fuels to support the operation and maintenance of 19 hydrogen fueling stations across the Golden State, which hopes to have 20 stations in operation by 2015, and 40 stations by 2016.
The tide is also rising for hydrogen fueling infrastructure elsewhere in the world: Germany now has 15 stations and has plans for 50 by the start of 2015 and 1000 by 2020. Japan currently has 17 stations, but hopes to have 100 by 2016. Korea plans to have 160 stations by 2020; the U.K. expects to have 15 stations by 2015 and 65 by 2020; and Denmark wants to install 15 stations by 2020.
Meanwhile, other automakers are launching hydrogen fuel-cell initiatives as well. Hyundai began selling a hydrogen-powered version of its Tucson SUV in certain California markets this summer. And at the LA Auto Show, Honda is displaying its latest, the FCEV Concept, which is to hit the market in 2016. The FCEV Concept builds on the company’s six-year-old FCX Clarity leasing program. It has a newly designed 100-kW fuel-cell stack that, like Toyota’s, features a power density of 3.1 kW/L. The fuel-cell system is one-third smaller than that in the FCX Clarity and therefore can fit entirely under the hood, Honda said. A single 10,000-psi hydrogen storage tank gives the FCEV Concept a range of 435 mi (700 km).
What perhaps distinguishes the Mirai from the others is that Toyota plans to add the car to its core product lineup rather than simply lease it to individuals. Toyota seems deadly serious about developing a hydrogen-powered “people’s car,” but Uchiyamada stressed that consumer education will be key to any eventual success. Whether fuel-cell vehicles are finally ready for the mass market “rests less on the car, and more on the ownership experience,” he said. After all, it took a decade or so for the Toyota’s global sales of hybrids to reach a million units, and today the Mirai faces a similarly long journey.
(To view a YouTube posting of the audio and Powerpoint slides from a recent U.S. Department of Energy Webcast reviewing SAE International standards on hydrogen refueling, go to http://energy.gov/eere/fuelcells/webinar-introduction-sae-hydrogen-fueling-standardization.)