Hydrogen-fueled cars are taking another step away from being cars of the future, inching towards a present day that might soon arrive. Just last month, three manufacturers exhibited fuel-cell powered cars at both the LA and Tokyo Auto Shows. Toyota, Honda and Hyundai all unveiled new fuel-cell vehicles (FCV).
John Krafcik, chief executive of Hyundai Motor America, called it, “a coming out party for hydrogen.”
And while it may be a while yet before these cars are commonplace on our streets, some of them are clearly on their way. That is largely due to the incremental improvements that have continued to emerge from the laboratories of major car companies.
Honda, Hyundai, GM Lead the Pack
Honda has reportedly reduced the size of its fuel cell stack by a third. That makes it small enough to stuff under the hood of a conventional car body. Hyundai says it has cut manufacturing costs by 50 percent over the past two years. Both unveiled new FCVs in Los Angeles.
Meanwhile, GM has been collaborating with Honda on a FCV, an effort that is also expected to produce a new vehicle soon.
According to MIT Technology Review, Toyota’s new FCV is expected be cost-competitive with Tesla’s all-electric Model S sedan which is classified as a battery electric vehicle (BEV).
Fuel Cell Vehicle vs. Battery Electric Vehicle
This raises the question as to what exactly is the difference between these two technologies. Despite common perceptions, they are really not as different as one might think. After all, both of them use electric powertrains. In fact, the only real difference between the two lies in how the energy is stored.
In the case of all-electrics, the energy is stored in an array of high-capacity batteries. In a FCV, the energy is stored as compressed hydrogen gas, which the fuel cell then converts into electricity as the car needs it. From that point on, the two are essentially the same, though different manufacturers will, of course, implement the drive trains in their own way.
To the end user, the practical difference comes down to how the two vehicles fill up. In the case of a BEV, the driver pulls up to a charging station. In the case of a FCV, the driver pulls up to a hydrogen “gas pump,” which, while more sophisticated than our gasoline pumps of today, essentially performs the same function of delivering fuel into a tank, though both the fuel and the tank are considerably different.
Hydrogen has the advantage of taking the same amount of time to fill up as gas-powered cars. Battery electric cars can take considerably longer to charge.
On the other hand, the electric grid is already in place, making an EV charging infrastructure a straightforward proposition. Putting a hydrogen charging infrastructure in place will be costly and time consuming.
There are now a number of scenarios that integrate electric vehicle charging systems as a key component of a smart city infrastructure, utilizing the thousands of potentially connected batteries as a storage medium for renewables in what is called a vehicle-to grid (V2G) architecture. Filling up a battery electric vehicle today is also less expensive.
Hydrogen can be produced directly from water through a fairly energy intensive process called electrolysis. It can also be reformed from natural gas or coal, though carbon dioxide is produced when it is created this way.
Both vehicle types can be considered pollution-free. FCVs release clean water vapor while BEVs emit nothing at all, but the question of which has a lower impact on greenhouse gas emissions must be passed through a life cycle analysis. The Argonne National Laboratory performed such a study, also known as a wells-to-wheels analysis.
The key for both types of vehicles depends upon how the electricity or hydrogen is produced. Because all public charging infrastructure in place today uses the electric grid, which is fed by a variety of sources including coal, natural gas and renewables, the only completely carbon-free BEV scenario is to charge your car at home where it’s connected directly to a solar PV installation. Certainly carbon-free EV charging can and will become available. Renewably-fed hydrogen systems that use electrolysis are available today.
Research on alternative methods of producing hydrogen is also making progress. Several efforts are looking at biological processes that emulate photosynthesis, either by using algae, through a synthetic process based on nano-particles called quantum dots and artificial light, or through the processing of simple plant sugars. These attempts could dramatically reduce the prices of hydrogen, making FCVs that much more competitive.
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