Optimal operation of residential fuel cell system with rapidly fluctuating energy demand

Household cogeneration systems using proton exchange membrane fuel cells (PEMFC systems) have attracted attention due to their high energy efficiency. To bring out a PEMFC system's performance, it is crucial to use effectively both the electric power and hot water produced from a PEMFC system. Therefore, the optimal scheduling problem of a PEMFC system is very important. However, there are difficulties due to uncertainty of household energy demand. A difficulty to which little attention has been paid so far lies in the difference between the scheduled electric power output and the actual electric power output of a PEMFC system caused by rapid fluctuations in electric power demand. In this paper, we propose a new method of dealing with this problem. In our method, we treat the energy demand as a random variable and calculate its probability density at each time step. Then a constraint that takes account of the energy demand fluctuations is defined through the probability density and is incorporated into the original optimal scheduling problem of the PEMFC system. Using our method, we can deal with rapid energy demand fluctuations in settings of the scheduling problem with long time intervals. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 8–17, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21064