Abstract
By considering change in energy transmission infrastructures, this paper describes a comparative assessment of energy systems with distributed generators such as a co-generation system (CGS). Material use measured by weight is used as an index for characterizing both technical and economical features of energy apparatuses. For various CGS penetration ratio (0%-100%), we evaluate the influence of CGS on overall weight and efficiency of energy systems. Depending on the CGS penetration ratio, we estimate the energy transmission infrastructure, i.e. electricity transmission lines and gas pipelines, by appropriately choosing voltage class or pipe size, and parallel number for minimizing the total weight. While the installation of CGS increases a peak demand of city gas on the whole, it may not reduce a peak demand of electricity because most CGS may not be operated during the summer season with very small hot-water demand, resulting in small contribution to reduction in electricity transmission infrastructures. In addition, because of relatively larger unit weight of CGS than that of large-scale power plants, the total weight of energy system increases with increasing CGS penetration ratio, while energy efficiency of the total system is increased also. The results suggest that individual CGS should be operated to avoid the installation of additional material use for gas transmission infrastructures for developing environmentally friendly energy systems.
