Water Energy Resources of the United States with Emphasis on Low Head/Low Power Resources: Appendix C - Validation Study

Abstract

Analytical assessments of the water energy resources in the 20 hydrologic regions of the United States were performed using state-of-the-art digital elevation models and geographic information system tools. The principal focus of the study was on low head (less than 30 ft)/low power (less than 1 MW) resources in each region. The assessments were made by estimating the power potential of all the stream segments in a region, which averaged 2 miles in length. These calculations were performed using hydrography and hydraulic heads that were obtained from the U.S. Geological Survey’s Elevation Derivatives for National Applications dataset and stream flow predictions from a regression equation or equations developed specifically for the region. Stream segments excluded from development and developed hydropower were accounted for to produce an estimate of total available power potential. The total available power potential was subdivided into high power (1 MW or more), high head (30 ft or more)/low power, and low head/low power total potentials. The low head/low power potential was further divided to obtain the fractions of this potential corresponding to the operating envelopes of three classes of hydropower technologies: conventional turbines, unconventional systems, and microhydro (less than 100 kW). Summing information for all the regions provided total power potential in various power classes for the entire United States. Distribution maps show the location and concentrations of the various classes of low power potential. No aspect of the feasibility of developing these potential resources was evaluated.