Comparative analysis of geothermal power plant designs suitable for Malawi’s Chiweta geothermal field

Abstract

Energy is the engine that drives the economy of a country. Unfortunately, Malawi experiences insufficient electricity generation capacity to support its economic activities. Located within the East African Rift System (EARS), which is one of the hottest geothermal zones in the world, Malawi is deemed to have significant potential geothermal energy resources that could be utilized. However, despite its favourable location, Malawi has been slow in developing production from its geothermal resource. Geological studies indicate that a geothermal system is located in Malawi with a subsurface reservoir temperature range of 169-249°C, which has been manifested through hot springs. Studies of hot springs like Chiweta indicated that the resource could be developed for electricity generation as well as direct utilization. Based on Lindal’s diagram of geothermal utilization (Ragnarsson, 2006), the Chiweta geothermal field temperature falls in the category suitable for electricity generation. This report analysed the various geothermal power plant designs suitable for development in Malawi. The analysis covered both technical and economic factors. The report proposes the power plant designs best suited for Chiweta field in Malawi: the basic binary power plant at reservoir temperatures below 210°C; and the basic hybrid power plant at a reservoir temperature of 240°C. Further studies are proposed to confirm the resource and its subsequent development as well as other potential utilization methods for the resource.