Fuel cell innovation
The 250-kilowatt fuel cell located in the Bewag Fuel Cell Innovation Park in Berlin has been running since June 2000 to show the public what a future hydrogen economy could look like. It is complemented by a 10-kilowatt photovoltaics plant.
Fuel cell technology was first developed in 1839 by Welsh justice and physician Sr. William Robert Grove. His contemporaries largely underestimated the importance of his discovery, and fuel cells were forgotten. The technology was resurrected in the 1950s, however, against the backdrop of the Cold War. Space travel and military technology required compact and powerful energy sources and fuel cells fit the description.
Because batteries are too heavy for spacecrafts, NASA decided to use electric power from fuel cells beginning with its Apollo program. Today, energy and space efficient fuel cells are being used for vehicle engines, residential heating, systems as big as power stations and as small as mobile phones and computers.
The Bewag project is a joint venture of five power utilities at a cost of about $350 million – about 40 percent funded by the European Commission since the project is expected to help the regional European economy. The fuel cell is only several feet long – about the size of a bathroom or utility room. The photovoltaic demonstration project is a pyramid-shaped room of glass windows that is no larger than an annex of a large office building and it looks much like a greenhouse.
While there are many types of fuel cells, this one is a PEM (proton exchange membrane) fuel cell, which is a small space-saving system that operates at about 90° C (194° F). The cell can be used to heat water for residences to 75° C (167° F).
In principle, all fuel cells consist of two electrodes, which are separated by a medium, called an electrolyte, that produces and conducts electricity. Hydrogen (or other fuels such as ethanol, methanol and gasoline that can be converted into hydrogen) is fed to one of the electrodes and oxygen to the other. Without the electrolyte, the two gases would mix and rapidly combust or detonate in a reaction.
The electrolyte (which can be liquid or solid with a membrane structure) , causes a controlled electrochemical reaction. Instead of burning violently, hydrogen ions with a positive charge accumulate at one of the electrodes (anode), and negatively charged oxygen ions at the other electrode (cathode). This creates an electrical voltage between the two electrodes, similar to the poles of a battery. This voltage can be put to use by connecting the electrodes to an exterior circuit. The PEM used at Bewag is coated with a thin platinum catalyzer and a gas-permeable electrode made of graphite paper.
The fuel cell process basically reverses the process of electrolysis, which many may remember from school experiments. In electrolysis, electric power decomposes water into oxygen and hydrogen. The fuel cell, however, generates electrical power and heat from hydrogen and air.
The fuel cell demonstration we saw was surrounded by an educational park, about the size of an average school playground project. Bright posters explain how fuel cells work. Today, fuel cells have many applications from powering spacecrafts and submarines to running vehicle engines, residential heating systems, mobile phones and computers. Some day large power plants could be replaced by millions of residential fuel cells. A good source of information on fuel cell projects worldwide including the Bewag project in Berlin is
http://www.fuelcellpark.com.
The Munich airport houses a hydrogen fuel cell project that started in 1997 at a cost of $40 million – half funded by the state and half by industries. The project features buses that are powered by fuel cells.
SOURCE:
WI Department of Natural Resources
http://dnr.wi.gov/
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