Fuel Cells: The giant batteries of the future
Fuel cells are an old technology, which, mainly due to material problems, has not, as yet, been commercially introduced. Present material science may make them a reality soon in specialized applications like, co-generation and advanced gas turbine combined cycles. The Solid Oxide Fuel Cell (SOFC), compared to other fuel cell types, is considered to be the most desirable fuel cell for generating electricity from hydrocarbon fuels. This is because it is simple, highly efficient, while being tolerant to impurities and can internally reform hydrocarbon fuels. A big advantage to the SOFC is that both hydrogen and carbon monoxide are used in the cell, meaning that the SOFC can readily and safely use many common hydrocarbons fuels such as natural gas, diesel, gasoline, alcohol and coal gas. SOFC technology results in some of the high temperature waste thermal-energy being recycled back into the fuel. Because the chemical reactions in the SOFC take place at the high operating temperatures, air compression is not required. Especially on smaller systems where this results in a simple design, quiet operation and high efficiencies. In addition, exotic catalysts or cooling systems are not required. The objective of this project was the development of a 50kW SOFC testing plant, based on a concept produced by Siemens, of a multiple cell array with a metal separator plate. The behaviour of the cells and stacks were studied and improved, with considerable effort made in the various materials used in the different components of the system. The critical areas of technological development involved improved glass-ceramic bonds, ceramic cells and metal bipolar plates.
