Estimating the costs in lost power of alternative Snake‐Columbia Basin management policies

Abstract

This work, in part, describes a 51 dam, 56 time period long‐range simulation model of the hydropower system in the Snake‐Columbia basin, including projects on those two rivers and on major tributaries thereof. The model is then applied to study a series of alternative basin management scenarios, and the consequences in lost power of these scenarios are evaluated economically. With 56 time periods and 51 projects (some having as many as five data sets), computational efficiency in a restricted computing environment is important. Efficiency in this model was achieved via use of ‘French Curve’ cubic spline data fits, together with fast pointers to carefully defined data structures. In addition, care was taken to couch the model in a setting making it accessible to use by nonprogramers, in a quasiconversational mode. Some technical detail on the implementation of the model is included in the paper. Mention is also made of another model developed during this effort, called PASO (Peaking Alternatives System Operation), a heuristic look ahead model now operational and available to interested users. Discussion of the validation procedures for both models is involved. The ‘firm power’ capability of the hydropower system in the Pacific Northwest is that maximal (monthly or biweekly) energy production which the system could produce during a 44½‐month ‘critical period’ of extremely low historical flows. In years of higher, more normal flows, the hydropower system can generate power substantially in excess of the firm capability. This ‘secondary’ power ebbs and flows annually as a function of many things, and it therefore seemed most relevant to focus studies of alternative basin management schemes on firm power production. Accordingly, the work assumed the historical flows of the period July 1, 1928‐June 30, 1932, a period of time including the critical period. The model and flow data was applied to the series of alternative basin management schemes, each selected for its environmental and/or political interest. The impact of each management scheme was then evaluated in terms of lost or foregone power against a ‘base regulation’ in which the objective was to generate as much power as possible over the critical period. Lost power was conservatively evaluated at 35 mills per lost kilowatt‐hour for baseload, with much higher costs possible for lost peaking.