Fuel cells have been generating energy cleanly and efficiently for about 75 years, but not so efficiently that they've been appropriate for use in a home.
Now that's about to change. Two German companies, the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) in Dresden and the Vaillant Group in Remscheid, have joined forces to develop a fuel cell system that uses gas to generate household heating and electricity.
The Fraunhaufer-Vaillant system uses solid oxide fuel cell (SOFC) technology to generate electricity in a combination of oxygen and hydrogen. The system operates at higher temperatures than alternative fuel cell technology – 850 degrees Celsius (1,562 degrees Fahrenheit), compared with 80 degrees Celsius (176 degrees Fahrenheit) – making it inappropriate for use in cars, for example, but it's suitable for heating air and water in a home.
What's more, these new cells avoid the use of platinum, which is a common ingredient in previous fuel cells, and that greatly brings down the cost of a system for home use.
The thing to remember is that, for the Fraunhaufer technology, there is no such thing as single solar cell. "One always speaks of a fuel cell system," says Fraunhaufer's Dr. Matthias Jahn. A single cell, about the size of a CD, produces just one volt, not nearly enough to generate a useable amount of electrical power. Cells must work as a group, and "we call the groups stacks," Jahn says.
The Fraunhaufer-Vaillant systems are fed gas through a normal utility connection, where the gas is converted into a mix rich in hydrogen. This gas then reacts with the with the fuel cell stack, in what's called "cold combustion," and generates heat and electricity. An afterburner is included to keep the process efficient and clean.
The system is about the size of a residential gas heater and can, in fact, replace the old heater to upgrade a home. But the upgraded device would produce not only heat, but also a kilowatt of electricity, about enough for a household of four.
Already, 150 of the units are in homes in Europe to troubleshoot the technology. Meanwhile, Fraunhaufer and Vaillant are working to reduce the cost and increase the longevity of the devices.