Air Quality Assessment for Development Options at Olkaria Geothermal Field in Kenya

Abstract

Utilisation of geothermal energy for direct and indirect uses is inexorably gaining momentum in many parts of the world endowed with the resource. Kenya has plentiful geothermal resources estimated to be over 10,000 MW that have not been exploited to full potential. The power demand in Kenya exceeds the supply and has been growing at 8% per annum. Consequently, the County has developed ambitious strategy, and intends to develop 5,000MW by the year 2017, which is about 3 times the existing capacity. Out of this, 700 MW is expected to be generated from Olkaria Geothermal Field. Olkaria I & II Geothermal Power Stations are located within a national park, at close proximity to commercial flower farm and ~5 km South of Lake Naivasha which is a Ramsar site. Hence there is need to consider the cumulative effects of hydrogen sulphide gas emitted from the Power Plants. This study therefore assesses the potential air quality impacts associated with the proposed development options at Olkaria Geothermal Field. Calmet and Calpuff dispersion models, which are recognised by US EPA, have been employed to assess the air quality associated with emissions from the proposed geothermal expansion at Olkaria. Three different emission scenarios, which represent the development options of the Power Plants have been considered.