Analysis of Environmental Load and Marginal Cost for Cogeneration System

Abstract

Cogeneration system (CGS) is one of the promising options to improve CO₂ emission of electric power generation systems in Japan. The study aims at clarifying energy performance and CO₂ emission factor of various CGS technologies such as diesel engine, gas engine, gas turbine and fuel cell.
In the study we propose a new method to convert net heat supply of CGS including the absorption typed heat pump into equivalent electricity comparing with energy performance of the electric typed heat pump.From the method it is deduced that CO₂ emission factor of CGS is stood for by kg-CO₂/kWh. The method enables to calculate the CO₂ emission factors of various CGS technologies and compare their factors of CGS with those of electric power generation technologies.
The study also analyzes marginal costs of CO₂ improvement if CGS is installed into the system of the existing electric power generation mix. The marginal costs are calculated for two different CGS installations; the supply option for the increased electricity demand and the substitute option for the existing power plant with the same fuel as CGS. It is clear that GE and PAFC are the promising CGS options whose marginal costs are lower among various CGS technologies.