A fuel cell vehicle (FCV) is an electric vehicle that uses a fuel cell rather than a battery to provide electricity for movement. While a standard electric vehicle battery must be recharged after all its fuel has reacted, a fuel cell is a "refillable battery." Fuel cells have also gained worldwide attention as a clean power source for hybrid electric vehicles (HEVs).
Fuel cell vehicles are equipped with other technologies to increase efficiency, such as regenerative braking systems that capture the energy lost during braking. Therefore, current hybrid technologies reduce petroleum consumption and provide lessons about batteries, energy storage, and complex electronic controls that may apply directly to future transportation technologies. With a well developed hybrid electric infrastructure, the transition to fuel cell hybrids will be smoother and less costly.
How do we produce hydrogen?
Hydrogen has the most potential as an energy carrier to be used in fuel cell vehicle systems. Although it is the simplest and most abundant element in the universe, hydrogen is never found alone on earth -- it is always combined with other elements such as oxygen and carbon. Hydrogen can be extracted from virtually any hydrogen compound and is the ultimate clean energy carrier. It is safe to manufacture, and hydrogen's chemical energy can be harnessed in pollution-free ways. Nonetheless, the energy required to extract the hydrogen component consumes more energy than the energy output emitted as it burns (in the fuel cell).
There are several ways to create hydrogen. The two most established methods are:
- Steam methane reforming (SMR): Steam reforming converts methane (and other hydrocarbons in natural gas) into hydrogen and carbon monoxide by reaction with steam over a nickel catalyst. This reaction produces carbon emissions. Moreover, production via SMR means that the price of hydrogen is acutely dependant on the price of natural gas. However, this is the most "efficient" method to produce hydrogen.
- Electrolysis: Using electricity, it is relatively easy to split water molecules to create hydrogen and oxygen. Hydrogen production via water electrolysis is the most forward looking method, as it means that hydrogen can be produced from renewable energy sources. Solar photovoltaic, wind, concentrating solar power, geothermal, hydro and other renewable sources can create a clean source of electricity that could be used for hydrogen production; if implemented and designed properly, this hydrogen production could create a renewable supply for our transportation fuel needs.
This diagram depicts the process of hydrogen production via electrolysis
What are the disadvantages of using hydrogen as a transportation fuel?
Hydrogen use in transportation does have disadvantages. Storing hydrogen onboard the vehicle has been a challenge because of hydrogen's lower energy density. Conventional gasoline has four times the energy density of liquid hydrogen (i.e. can supply 4 times the energy output per gallon). Therefore, storing enough hydrogen to attain the comparable range of conventional vehicles requires large pressurized cylinders, which adds weight to the vehicle and can impact cargo space.
Moreover, hydrogen production continues to be expensive because of its lack of availability. However, these costs will continue to fall if policies are implemented and money is directed toward developing this important sector of the energy industry.
Where and how will I get hydrogen to fuel up my fuel cell car?
Because it is a relatively new and underdeveloped technology, there are a limited number of fuel cell vehicles and hydrogen fueling stations in the world. Click here (PDF) for a list of worldwide hydrogen fueling stations. There are 16 hydrogen fueling stations in the state with 10 more scheduled to come online by next year. Current and planned hydrogen fueling stations for Southern California can be found at Hydrogen Fueling Stations and Vehicle Demonstration Programs.
California has ambitious plans for a well developed hydrogen infrastructure within the next several decades. Governor Schwarzenegger has pushed forward a “Hydrogen Highway Blueprint Plan” to expedite the development of hydrogen fueling stations and promote their broad availability by 2010. These policy developments can be found at the California Hydrogen Highway Network webpage. For a candid discussion on the prospect of a hydrogen based market, see this Popular Science article.
Fuel cell vehicles and the hydrogen fueling infrastructure are currently in the development stages and are still very expensive. However, it is important to be familiar with the technology and the policies. Hydrogen and fuel cells will become increasingly important for various sectors of the economy, especially the transportation sector.
Local Hydrogen Fueling Stations
In 2003 Chula Vista constructed one of the first hydrogen fueling stations in the state with grants by the Department of Energy. The hydrogen is produced by electrolysis from a photovoltaic array and supplies up to 60 kg of compressed hydrogen per day. The City of Chula Vista also began leasing the Honda FCX fuel cell vehicle (shown on right) in November 2004 for a period of two years. The FCX has a range of up to 160 miles and seating for four people, making it practical for a wide range of real-world applications.
Fuel Cell Links:
Dept. of Energy EREN Fuel Cell page
California Stationary Fuel Cell Collaborative
Dept. of Defense Fuel Cell Demonstration Program - good operational data on the ONSI PC25 Phosphoric Acid Fuel Cell
Fuel Cell Vehicle Links:
California Fuel Cell Partnership: Driving For the Future
Fuel Cell Car and Experiment Kit
EPA Fuel Cells and Vehicles page
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