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Fuel cells provide a range of critical benefits that no other single power technology can match.
A fuel cell converts the chemical energy of hydrogen and oxygen directly to produce water, electricity, and heat. They are therefore inherently clean and efficient and are uniquely able to address the issues of environmental degradation and energy security. They are also safe, quiet and very reliable.
Fuelled with pure hydrogen, they produce zero emissions of carbon dioxide, oxides of nitrogen or any other pollutant. Even if fuelled with fossil fuels as a source of hydrogen, noxious emissions are orders of magnitude below those for conventional equipment.
They offer significant improvements in energy efficiency as they remove the intermediate step of combustion and mechanical devices such as turbines and pistons. Unlike conventional systems, they operate at high efficiency at part load. Also, unlike conventional plants, their high efficiency is not compromised by small sizes. High efficiency saves fuel and reduces CO2 emissions.
Fuel cell power plants have demonstrated unprecedented reliability and durability that is significantly better than conventional equipment. The absence of combustion and moving parts means that fuel cells can run continuously for long periods before servicing and they are far less prone to breakdown. They promote energy security and will assist the transition to renewable energy sources. Fuel cells can use hydrogen derived from a variety of sources, including natural gas and coal, and renewables such as biomass or, through electrolysis, wind and solar energy.
Fuel cells offer utilities the opportunity to provide customers with an added value energy service that is not subject to the same competitive or regulatory pressures as exist for conventional electric supply and will be able to do so at overall lower cost.
Principle of operation of a typical fuel cell:
- When hydrogen is fed into a fuel cell, a catalyst on the anode converts the gas into negatively charged electrons (e-) and positively charged ions (H+).
- The electrons (e-) flow through an external load to the cathode.
- The hydrogen ions (H+) migrate through the electrolyte to the cathode where they combine with oxygen and the electrons (e-) to produce water. Individual cells produce a small voltage. They are arranged in 'stacks' to provide the required level of power.
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