A Method for Evaluating Performance Uncertainty and Optimizing Data Accuracy in Geothermal Power Plants

Abstract

The profitability of a geothermal power plant is directly affected by its thermal performance. Therefore, a method has been developed for determining the uncertainty in calculated power plant performance parameters and finding the most economical level of instrument data accuracy. By applying the laws of calculus to the performance parameter equations it is possible to determine the impacts of data accuracy on the performance parameter uncertainty. Optimum profitability is based on minimizing operation and mainenance costs by monitoring performance and optimizing the number of performance-related maintenance procedures. There is a tradeoff between the cost of maintenance and the benefits of reduced steam consumption and/or increased power output,which are impacted by the frequency of particuular maintenance procedures. Performance benefits accrue as maintenance frequency is increased, at the expense of higher labor and material outlays and possible outage time. This differential cost is a function of three variables: 1) the operating cost of degraded performance, 2) the maintenance cost of corrective action, and 3) the performance degradation rate. The value of instrumentation accuracy relates to the ability to determine the performance degradation rate.