Optimized gas waste management strategies for geothermal projects for Caribbean Small Island Developing States (SIDS)

Abstract

Geothermal energy is considered internationally as an environmentally friendly and renewable energy resource. Non-condensable gases (NCGs) are a natural component of all geothermal systems and are normally released to the atmosphere during geothermal electricity production. NCGs contain greenhouse gases (GHGs) such as carbon dioxide (CO2) and methane (CH4) along with hydrogen sulphide (H2S), hydrogen (H2), nitrogen (N2) and other gases in trace quantities. This report investigates emissions of three geothermal wells in the Eastern Caribbean islands of the Commonwealth of Dominica, Saint Lucia and Montserrat, all classified as Small Island Developing States (SIDS). The report quantifies the three islands’ GHG emissions in proportion to their proposed plant size for electricity production. These emissions are compared to commitments submitted as part of their Nationally Determined Contributions (NDC) under the 2015 Paris Climate Agreement. The results indicate that the estimated GHG emissions from the three islands vary significantly, although the systems are located within the same Caribbean volcanic arc. The report investigates a suitable assessment method for gas abatement technology based on GHG emissions. Geothermal systems vary between locations but for Caribbean SIDS it is important that the emissions potential is carefully evaluated when considering the reason to use geothermal as an alternative source of energy to conventional systems. Geothermal power plants that are properly designed can minimize emissions and provide additional benefits to the surrounding communities.