What are fuel cells and hydrogen?
Fuel cells generate electricity by electrochemically combining hydrogen and oxygen. On a life-cycle basis, they can produce zero or very low emissions, depending on the source of the hydrogen. Fuel cells are energy-conversion devices that utilize hydrogen and other fuels.
Fuel cell applications will likely be used in portable and stationary power devices, possibly followed by transportation applications. Most automobile manufacturers are now working on later prototypes for hydrogen fuel cell vehicles. Due to the variety of fuels available for conversion to hydrogen, fuel cells are a viable energy technology, one that may offer significant environmental, energy efficiency, supply and economic benefits. But there are still many barriers to their use in vehicles, including the lack of a hydrogen distribution infrastructure, high capital costs for fuel cells and hydrogen-production technologies, and challenges related to hydrogen storage.
In principle, fuel cells are similar to batteries. The main difference is that batteries store electrical energy, while fuel cells generate electricity continuously as long as an external fuel source is supplied.
Fuel cells convert chemical energy into electrical energy by combining hydrogen or hydrogen-containing fuels and oxygen from the air.
In the fuel cell the electric current flows from the anode to the cathode. An electrolyte separating the anode and the cathode acts as a “one-way door,” allowing protons to travel across the electrolyte while forcing the electrons to travel through the external circuit, producing electricity. Various types of fuel cells use different electrolytes, with different electrochemical reactions occurring, but the overall reaction is the same: hydrogen and oxygen combine to form water and release energy.
Hydrogen can be extracted from thousands of compounds, including natural gas, water, sugar and many petroleum products. The extraction of hydrogen requires energy, making hydrogen an energy carrier rather than an energy source.
The first hydrogen fuel cell was discovered by Sir William Grove (of the United Kingdom) in 1839. Fuel cells started to become practical in the late 1950s, when British scientist Francis Thomas Bacon demonstrated a working stack of alkaline fuel cells and later licensed the technology to Pratt & Whitney. During the 1960s, the National Aeronautics and Space Administration (NASA) and the U.S. military began to develop fuel cells for spacecraft and remote military establishments. All manned spacecraft still use fuel cells to produce power.
In Canada, the National Research Council Canada , on behalf of Natural Resources Canada (NRCan), initiated the NRC Fuel Cell Program in 1982. The program purchased and installed a 40-kW phosphoric acid fuel cell, which operated from 1982 to 1995. The second project was a contract to Ballard Power Systems Inc. of Burnaby, British Columbia, to develop the polymer electrolyte membrane fuel cell. Also in the 1980s, the Department of National Defence (DND) conducted fuel cell work at its Defence Research Establishment Ottawa, and the University of Toronto was developing the alkaline fuel cell for transportation uses.
In the past two decades, private industry has become more involved in this work and, with continued support from government, has established Canada as a world leader in the development and commercialization of fuel cells and related products.
The world's first demonstration vehicle using only fuel cell technology to power the wheels was a 10-metre transit bus developed in 1993 by Ballard. With financial support from NRCan, DND, Industry Canada and the British Columbia government, Ballard has become one of the recognized world leaders in developing zero-emission proton exchange membrane fuel cells for transportation and other uses.
In 1998, Ballard joined forces with New Flyer Industries Ltd. of Winnipeg, Manitoba, to produce a full-sized, 12-metre electric bus powered by a hydrogen fuel cell. Between 1999 and 2001, transit operators ran six of these buses in Vancouver, British Columbia, and in Chicago, Illinois. The six buses, which stored fuel in compressed hydrogen cylinders (with a range of about 400 kilometres between refuellings), travelled more than 118,000 kilometres and carried more than 200,000 passengers during this successful trial. Information and experience gained during the project has helped Ballard develop the next-generation engine, which weighs 50 percent less than the previous generation.