First, why fuel cells? Today, there is tremendous interest in distributed generation. This interest is growing as the industry seeks new ways to cost-effectively supply 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 opens the door to new methods of producing power. Scaled for smaller plants, these methods offer more efficient use of natural resources and lower emissions into the atmosphere.

For nearly four decades, Siemens Westinghouse has been refining an energy source that is clean, highly efficient, and ideal for providing high quality power at small distributed sites. And that energy source is the solid oxide fuel cell, or SOFC.

"A fuel cell is a device that converts chemical energy directly into electricity and heat," Casanova told World Cogeneration.

There are several types of fuel cells, but all share the use of hydrogen as fuel. Some, like solid oxide fuel cells, can also handle carbon monoxide, which makes them more versatile when using fuels such as natural gas.

Siemens Westinghouse installed a 100 kilowatt cogeneration system in Westervoort, the Netherlands, in 1998. This system feeds power to the local grid and hot water to the district's heating system.

The electrical efficiency of this system is 46%, which means that nearly half of the fuel consumed generates electricity. The system is also producing zero sulfur dioxide and virtually no nitrous oxide, chemicals that cause acid rain. This performance is phenomenal when compared to the efficiency and emissions of large central power plants fueled by coal or natural gas.

The Westervoort installation is the first full-scale demonstration of SOFC technology. It will be followed by a 250 kilowatt commercial prototype SOFC cogeneration system.

In 2000, the world's first SOFC/Gas Turbine Hybrid System was installed at the National Fuel Cell Research Center in Irvine, California. The system includes a pressurized module integrated with a microturbine/generator for a combined output of 220 kilowatts.

This system is the proof of concept for the hybrid design and is the prototype for commercial hybrid systems.

In coming years, continued refinement of SOFC technologies and high volume manufacture will produce commercial systems that are an economical alternative to current methods of power generation.

SOFC cogeneration systems will provide power and heat to homes, businesses, and even small towns.

While SOFC/gas turbine systems will generate electricity for large commercial sites, industry, and cities, solid oxide fuel cell systems - from a few hundred kilowatts to megawatt class - will be the distributed generation plants of the future.