COST ESTIMATION OF UNDERGROUND COAL GASIFICATION IN JAPAN

Abstract

Underground Coal Gasification (UCG) is one of the methods of recovering energy from underground coal seams. In 1970’s and 1980’s, many basic studies and field tests on UCG were carried out in the USA. Although the activity on UCG has been interrupted, because of the recent low oil price in the world energy market, the technologies and concepts developed in this period are remarkable. Since the 1960’s almost no studies on UCG have been made in Japan. The authors made a cost estimation on UCG in JAPAN, applying the new technologies developed in the USA and data obtained in the field tests there. This study includes the selection of the best site for UCG in Japan from the viewpoint of geological conditions, the prediction of product gas component and the cost estimation. Two UCG methods, ELW (Extended Linked Well) and CRIP (Controlled Retracting Injection Point), were taken into consideration for cost comparison. Our assumption was gasification of one million tons of coal within a period of 10 years. The production cost of gases per heating value was estimated to be between US$0.029/MJ and US$0.045/MJ. Finally, the authors proposed a boring cost saving UCG method, STRIP (STream Method with Retracting Injection Point) method, for its further technical development.