Energy return on investment, energy payback time, and greenhouse gas emissions of coal seam gas (CSG) production in China: a case of the Fanzhuang CSG project

Abstract

The studies and development of coal seam gas (CSG) have been conducted for more than 30 years in China, but few of China’s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question: Should the government continue to vigorously support the development of the CSG industry? To provide a reference for policy makers and investors, this paper calculates the EROIstnd [a standardized energy return on investment (EROI) method], EROIide (the maximum theoretical EROI), EROI3,i (EROI considering the energy investment in transport), and EROI3,1+e (EROI with environmental inputs) of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time (EPT) and the greenhouse gas (GHG) emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROIstnd, EROIide, EROI3,1, and EROI3,1+e are expected to deliver EROIs of approximately 11:1, 20:1, 7:1, and 6:1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.