Risk Assessment of Critical Equipment Failure Mode. A Case Study of Olkaria 2 Geothermal Power Plant In Kenya.

Abstract

Recently in Kenya, there is massive investment in exploration of geothermal energy which is the key source of power to the national grid. However, despite considerable investment in geothermal power sources, in Kenya and many developing countries, few studies address the asset management (maintenance) aspects of existing facilities. Therefore the objective of this paper is to perform risk assessment of critical equipment failure modes in the power plant by using RPN and FMEA techniques. These techniques were considered for determining, classifying and analyzing common failures in the power plant. The first step involved failure data collection, structuring and analysing the reliability data. The next step involved performing risk assessment with a view of prioritizing critical sub-systems and the critical failure modes associated with the critical sub-systems identified. Risk assessment was done by applying RPN and cost-based FMEA analysis where risk is measured in terms of cost of failure of a sub-system. As a result, an appropriate risk scoring of occurrence, detection and severity of failure modes and computing the Risk Priority Number (RPN) for detecting critical sub system failure is achieved. FMEA technique was then applied to determine the critical failure modes for the critical sub systems identified using RPN. The study found out that the critical sub systems experiencing frequent failures were gear reducer, hot well motors and vacuum pumps. The failure costs associated with these sub systems upon downtime are USD 19,930.67, USD 12,911.27 and USD 8,651.20 respectively.