Life Cycle Based Carbon Footprint Assessment of Indonesian's Geothermal Energy Exploration Project

Abstract

Indonesia is committed to increase the contribution of renewable energy to at least 23 % of the total Indonesian energy mix by 2025. The geothermal energy resource of Indonesia could potentially help achieve this target, but there are environmental challenges associated with geothermal energy exploration. This study is aimed to estimate the carbon footprint of the geothermal exploration project using a life cycle assessment (LCA) approach. Literature published to date did not consider the use of LCA to specifically assess the environmental impacts of geothermal energy exploration. A geothermal energy exploration project in West Java, Indonesia, has been taken as a case study to conduct an LCA considering four main activities, namely land clearing, access road improvement, slim-hole well pad, and standard-hole well pad construction. ReCiPe impact assessment analysis was used to convert inputs and outputs of these activities to carbon footprints of 1 m2 of area of geothermal energy exploration. The result showed that the total carbon footprint of geothermal energy exploration stages was 53.2 kg CO2-eq/m2/y. The two most significant contributors to carbon footprints were the construction of a standard-hole well pad (56 %) and a slim-hole well pad (43 %). Diesel fuel and chemicals were two main carbon footprint sources of geothermal energy exploration project. In terms of inputs, the utilization of caustic soda for neutralization during the drilling activity contributed 64.5 % of the total carbon footprint, followed by diesel fuel consumption (27 %), bentonite (4.04 %) and barium sulphate (4.43 %) for the high carbon footprint for standard-hole well pad construction. The effective utilization of caustic soda and diesel by preparing standard operational procedure (SOP) and implementing ISO quality and environmental management systems (ISO 90001 and 14001) could increase the environmental performance of geothermal energy exploration.