Geothermal Energy Development of Sri Lanka

Abstract

Although Sri Lanka is not located in tectonically active margins and active fault zones with thermal signatures, there are many occurrences of hot springs in the country. There are two major hypotheses explaining the origin of geothermal fields in Sri Lanka, the Highland- Vijayan (H/V) boundary which is an inactive plate boundary passing through the country as a source of hot springs being the oldest. Although some of the hot springs are apparently arranged along the H/V boundary, it could be observed that most of them have been deviated from it. The dolerite dykes as a source of hot springs is the other hypothesis which has been substantiated by the surface evidence and geophysical exploration results. Among the eight recorded hot spring sites in the country, the highest temperature is observed at Kapurulla hot spring in Tampitiya area. The other sites of hot springs are Mahapelessa in Hambanthota, Kanniya in Trincomalee, Rangiriulpotha in Gomarankadawala, Nelumwewa in Polonnaruwa, Wahawa in Padiyatalawa, Maduruoya and Mahaoya. All these sites have acceptable surface temperatures for low enthalpy geothermal utilization. The scope of the paper to be presented is to provide an insight into thegeothermal energy exploration in Sri Lanka, with a focus on the developments over the history. In the first phase, the surface studies of manifestations, geological and surface geochemical explorations have already been completed and found that the surface activities have a direct implication with the geological structures.The geophysical studies which are of paramount importance for the modelling of the geological structures are currently being conducted. We also wish to discuss the apparent barriers and the challenges expected in the process of geothermal energy exploration in the country.