Solid Oxide Fuel Cells Introduction
Today there is tremendous interest in distributed power generation because it promises to be environmentally friendly and offers new ways to supply cost-effective power in a competitive, deregulated marketplace. Distributed energy sources also hold great promise in meeting increased demand for higher quality, more reliable power.
And by its design, distributed generation can provide companies with greater control over their power supply and opens the door to new methods of producing power. Scaled for smaller plants, these methods can offer more efficient use of natural resources and lower emissions.
For more than 40 years Siemens and Siemens Power Generation has been performing basic research and product development of an energy conversion technology that is clean, highly efficient and ideal for providing high quality power at small distributed sites. That technology is the solid oxide fuel cell, or SOFC.
Siemens Power Generation is developing tubular SOFC technology with the support of the US Department of Energy's (DOE) advanced fuel cell research program and by the German Ministry of Economics and Labor (BMWA).
Siemens Power Generation has formed a new business division, the Stationary Fuel Cells (SFC) division, dedicated to completing the commercialization of solid oxide fuel cells. SFC is currently in the pre-commercial phase of its business plan and expects to have its first commercial product available in 2012.
Siemens Power Generation tubular SOFC technology
The Siemens Power Generation solid oxide fuel cell (SOFC) is made up of an electrolyte and two electrode layers in a unique tubular design. This design eliminates the need for seals required by other types of fuel cells, and also allows for thermal expansion. In a tubular SOFC design, air flows through the interior of the cell, and fuel flows on the outside of the cell. At elevated temperatures, the oxygen in the air ionizes and the resulting ions flow through the electrolyte and combine with the fuel on the cell's exterior. This is an electrochemical reaction, so electrons are released. With proper connections, they can flow through an external circuit as electricity.
Siemens Power Generation is the world leader in SOFC. This is due largely to the unique tubular cell and the simple design of the stack. The stack is cooled using process air, and during normal operation consumes no external water. It also has integrated thermally and hydraulically within its structure a natural gas reformer that produces the hydrogen and carbon monoxide utilized by the cell. Also, except during start up, no external heat source is needed.