SOFC Performance Contributed for Greenhouse Gas (CO2) Reduction of 25% below 1990 Levels by 2020

Abstract

We investigated the conceptual design policy for CO 2 gas reduction of 25% below 1990 levels by 2020. The electric power supply of Japan in 2020 was estimated 956.5 TWh. The LNG generation plant and the generation plant using renewable energy are the proper generation method from the point of view of 1) safety, 2) CO 2 gas reduction, 3) economy, 4) resources, and 5) load following operation. We proposed an electric power supply system that the 80% of electric power supply of Japan in 2020 was supplied by SOFC-GT-ST hybrid system using LNG and the rest was supplied by generation plant using renewable energy. For the conceptual design policy for CO 2 gas reduction of 25% released from generating station in 1990, we showed that SOFC-GT-ST hybrid system with generating efficiency of 70% (HHV, AC) was useful in reducing CO 2 gas. In this system the generating efficiency of SOFC was required above 60% (HHV, DC). To improve the generating efficiency and the volumetric power density of SOFC, new bifacial flat tubular cell structure based on numerical analysis was proposed. Main feature of new cell structure is shown below. 1) 2 mm thin cell to shorten the current path and reduce the cell volume. 2) Interconnector divided into nine to shorten the current path. 3) Covering the cathode surface with the auxiliary electrode to reduce the cell resistance. 4) Porous flow path of anode to avoid partial flow. Prototype of proposed cell was analyzed and achieved 60% (HHV, DC) of generating efficiency and 2 W/cm 3 of volumetric power density when the cell voltage was 0.77 V.© The Electrochemical Society of Japan, All rights reserved.Keywords : SOFC, SOFC-GT-ST Hybrid System, CO 2 Gas Reduction, Bifacial Flat Tubular Cell