Kenya is ranked 5th globally in geothermal development. Geothermal exploration started around 1950's in Olkaria and Bogoria. In power plant development, the main parameters applied are power generated and exergy, among others. Well head installation in Olkaria was adopted in 2012 has a total installed capacity of 81 MWe. The well head units in Olkaria are all single flash type. Single flash are the main power plants globally. In this study exergy analysis and parametric comparison of conventional single flash generating 142 MWe and well head of 7 MWe is presented. The plants are optimized based on maximum power generated, highest efficiencies and lower parasitic loads with the focus on the non-condensable gas removal. The obtained results show that well head and single flash operates in the same trend with different optimization objectives. Well head has the best exergy efficiency at 64% and least exergy destroyed in the separator.