Planar solid oxide fuel cell single cells, removed from the frame. Source: Research Centre Jülich
In a new world record for stationary applications, a planar solid oxide fuel cell (SOFC) built at the Jülich Institute of Energy and Climate Research in Germany has exceeded an operating lifetime of 40,000 hours. This exceeds the previous limit of commercial use in stationary applications, and the operation corresponds to a period of 5 years. Because of the good efficiency and high operating temperature targets, researchers plan to develop this fuel cell type for particular stationary applications such as distributed systems or to supply households.
The Jülich “stack test” fuel cell is not operated in a laboratory environment. It has all of the components that will comprise a possible commercial product later. It is powered by hydrogen, which is converted with an efficiency of 64% in the cell into electricity. Other fuels such as natural gas can be implemented with higher efficiency, as other studies have shown. While fuel cells in vehicles are typically asked to operate at least 5,000 to 10,000 hours, economical operation in stationary applications require a minimum term of five years or the equivalent of 40,000 hours. This value was surpassed for the first time in a long-term test with Jülich’s solid oxide fuel cell.
With this new level of performance, the fuel cell has reportedly exceeded the expectations of researchers, who started their work two years ago to build a fuel cell with a maximum lifetime of around 30,000 hours.
"The test has pleasantly surprised us. Although the industrial implementation would optimally be 60,000 to 80,000 hours, the level we have achieved shows that the long-term stability of the fuel cell is proved in principle," says Prof. Detlef Stolten, spokesman of the Jülich Research Center fuel cell.
The test system is made from materials which could also be used for producing a commercial product. Before that can happen, however, researchers say the cost will need to be optimized and the system proved not only on the test stand, but also under everyday conditions. The Jülich Institute of Energy and Climate Research together with the Central Institute of Technology (ZAT) aim to optimize the entire value chain and drive market development.
The longevity of the Jülich SOFC is partly a consequence of its relatively mild temperature of 700 C. Customarily solid oxide fuel cells operate at other than 800 to 1,000 C. The low operating temperature makes it possible to use relatively inexpensive materials and to operate the cell with a whole range of different fuels. Because of these properties, this new SOFC could be used in distributed systems, households, and industrial facilities, taking advantage of waste heat to supply electricity. Also being considered by researchers are on-board power supply applications in road vehicles, ships and aircraft.