Preliminary environmental impact assessment for the development of Tendaho geothermal area, Ethiopia

Abstract

The Tendaho geothermal field is one of two geothermal fields in the Ethiopian Rift Valley that has been explored by deep drilling. Six geothermal wells have been drilled to date, four of which are productive. There is a plan to progress the resource to development in three phases, which includes a small scale power plant, further deep drilling and a medium scale plant. In this report, analysis of the current status of the environment, environmental effects which the proposed developmental activity may entail and mitigating measures to be taken to reduce impacts to the level of insignificance, are discussed. The environmental regulations of Ethiopia are used as a guide line. The characteristics of the existing environment at Tendaho include: a flat topography, scarce wildlife, scarce vegetation, arid climate, limited surface water bodies, clean air, natural thermal features and sparse population. Impacts on the environment from deep drilling are predicted to be minimal and short term. Potential impacts of utilization of the resource on the environment are physical, chemical and socio-economic. The physical impacts on the geology and the landscape relate to construction activities and the abstraction of water from the reservoir. Given the chemical concentration of the geothermal fluids, the risk of contaminating the groundwater by waste water disposal is considered low. Air emissions during operation will cause no significant contamination of the air, since the gas content of the resource is low. The impacts on the socio-economic conditions are mainly positive, including a rise in employment opportunities and an indirect stimulation of rural development. All the impacts can be mitigated with careful management of the resource and implementation of appropriate environmental protection...