Using Untapped Proven Resources and Improving Efficiency of Flash Plants, by Retro Fitting Binary Cycle

Abstract

The East Africa Rift Valley has significant geothermal potential. With the exception of Kenya, that is one of the most active geothermal energy producer in the world, geothermal exploration and development in the other African regions have been limited up to now. Harnessing this untapped potential is of strategic importance for these countries growth. Developing a new steam field faces many challenges, which takes time, costs a significant amount of equity, has mineral risk, and face many challenges, environmental and regulatory. Frequently resources which have previously been drilled have been deemed uneconomical to use. Additionally, existing steam fields frequently use single flash, steam turbine power generation plants. Although efficient and reliable, a significant part of the total thermal capacity is lost in the liquid phase (hereinafter called brine). The following paper describes in detail how it is possible to safely and efficiently recover the energy contained in the brine from either existing, or unused resources. With developments in ORC technology it can now be economical to develop existing resources. In addition, just utilizing the energy contained in the existing brine of typical single flash plants, it is possible to add approximately 35% of the steam field rated electrical power output thanks to the Exergy GEX binary plant, based on its patented Radial Outflow Turbine (ROT). The paper will focus on case studies of both unused, and single flash plants.