Integrated Risk Assessment for Geothermal Energy Development and Evaluation

Abstract

This study uses a risk-assessment approach to examine how uncertainty and risk change as a function of the thermal drawdown calculation for an enhanced geothermal system (EGS). Using Monte-Carlo simulations, we calculate the uncertainty and integrated risk of the levelized cost of electricity (LCOE) that results from uncertainty in a variety of sub-surface parameter values. Three ensembles of simulations are created, each with the same uncertainties in the sub-surface parameter values but with different methods of calculating the thermal drawdown. Integrated risk assessment is an approach that simultaneously accounts for all uncertainties and other outside factors that may cause the actual future to deviate from its predicted future. Integrated risk is calculated as the sum of the consequence, C, multiplied by the range of the probability, ÄP, over all estimations of a given exceedance probability, n, over time, t. Here, consequence is defined simply as the LCOE, with the probabilities of achieving a particular LCOE a function of the uncertainty. The analysis assumes a realistic but fictitious EGS site with nine varied parameters that control the sub-surface conditions. A risk-based LCOE value is calculated for each ensemble along with correlation analysis to identify the parameters and conditions that contribute most to the risk.