We propose electric double-layer capacitor storage, which has quick response in the output or input of electricity but has a smaller capacity than normal secondary batteries, by application to a residential fuel cell cogeneration system to reduce spike-shaped electric power consumption. The method is expected to enhance the system utilization rate and to moderate the burdens on a power grid connected to fuel cells or other distributed generators. A low-pass filter method was introduced for balancing the power supply and demand, and leveling the power input from the grid. According to simulations performed using practically measured load patterns, the appropriate storage capacity is about 500 Wh for a household, and the fuel cell utilization rate or the grid burden improvement is increased by around 40% in comparison with the case of a system without storage capacity. It has been shown that, in an energy network method of five or more households, the storage capacity can be reduced to approximately 40% with extreme burden improvement of less than 90% of the stand-alone condition. We have also verified the practical operation and the performance of the method by using an experimental system. (C) 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 16-27, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20913
