Installation Plan of a Fuel Cell Cogeneration System

General Introduction

The summary of the 1st section is as follows. If energy-supplying microgrids can be arranged to operate with maximal efficiency, this will have a significant influence on the generation efficiency of the grid and will reduce greenhouse gas production. A means of optimizing the microgrid needs to be developed. Moreover, microgrids that use PEFC may significantly reduce the environmental impact when compared with traditional power plants. The amount of power supplied to the grid divided by the heating value of the fuel is defined as the system generation efficiency. The authors find that when a set of PEFCs and a natural gas reformer are connected to the microgrid in an urban area, the annual generation efficiency of the system slightly exceeds 20%. When a PEFC follows the electricity demand pattern of a house, it operates at a partial load most of the time, resulting in a low efficiency of the microgrid. A method of improving the generation efficiency of a fuel cell microgrid is proposed, where a supply system of power and heat with a high energy efficiency are constructed. In this study, a method of installing two or more microgrids is proposed (known as the partition cooperation system). The grids can be connected in an urban area to maximize generation efficiency. Numerical analysis shows that the system proposed in this study (which has an annual generation efficiency of 24.6 to 27.6%) has a higher generation efficiency than conventional PEFC systems (central generating systems have annual generation efficiencies of 20.6 to 24.8%).

The summary of the 2nd section is as follows. A fuel cell energy network which connects hydrogen and oxygen gas pipes, electric power lines and exhaust heat output lines of the fuel cell cogeneration for individual houses, respectively, is analyzed. As an analysis case, the energy demand patterns of individual houses in Tokyo are used, and the analysis method for minimization of the operational cost using a genetic algorithm is described. The fuel cell network system of an analysis example assumed connecting the fuel cell co-generation of five houses. If energy is supplied to the five houses using the fuel cell energy network proposed in this study, 9% of city gas consumption will be reduced by the maximum from the results of analysis. 2% included to 9% is an effect of introducing water electrolysis operation of the fuel cells, corresponding to partial load operation of fuel cell co-generation.