Combined Heat and Power: Efficient Utilization of Geothermal Energy, a Case Study of Menengai Well MW-03

Abstract

After drilling a geothermal well, various parameters are evaluated to establish the energy potential of the well, the chemistry of the geothermal fluid as well as the other factors that may affect the wells output during exploitation. Geothermal energy can be used for both electricity generation and Direct Use applications. Depending on the evaluated parameters, electricity generation can either be by a condensing unit or by use of binary technology. Hot geothermal brine can be used as a source of thermal energy for industrial processes and can be cascaded to various applications depending on the energy requirements. Well MW-03 was one of the first exploratory well to be drilled in Menengai, due to its low wellhead pressure (1.5 bara), it cannot be connected to the steam gathering system which will be operating at a minimum of 6 bara. The well 66 t/hr of geothermal fluid at an enthalpy of 1250 Kj/kg and hence has substantial energy for both electricity generation (using binary technology and for direct use applications. The well is proposed to supply both electrical and thermal energy to a milk processing demonstration plant, after which the energy is cascaded to laundry facilities and domestic water supply to the drilling campsite, greenhouse heating and aquaculture heated ponds and a swimming pool. An analysis of the available energy and fluid chemistry of well MW-03 and its optimised utilization, through cascading, is evaluated in this paper.