Idaho Power’s largest energy resource consists of the utility’s 17 hydroelectric plants along the Snake River. Sub-average water supply in recent years has highlighted the need for optimal water utilization. PI System products provide Idaho Power the means to calculate in real-time the most efficient use of water at the hydro generator and plant level. By transforming the existing paper efficiency curves to a tabular format and collecting real-time water flows and net head levels via SCADA, a built-in PI System function called Bi-Linear Interpolation can be used to calculate the real-time efficiency. This project effectively replaced the tedious work of reading paper curves and gave operators the power to make optimal use of water along the Snake River.