Climate change effects on high-elevation hydropower system in California

The high-elevation hydropower system in California, composed of more than 150 hydropower plants and regulated by the Federal Energy Regulatory Commission (FERC), supplies 74 percent of in-state hydropower. The system has modest reservoir capacities and has been designed to take advantage of snowpack. The expected shift of runoff peak from spring to winter as a result of climate warming, resulting in snowpack reduction and earlier snowmelt, might have important effects on hydropower operations. Estimation of climate warming effects on such a large system by conventional simulation or optimization methods would be tedious and expensive. This dissertation presents a novel approach for modeling large hydropower systems. Conservation of energy and energy flows are used as the basis for modeling high-elevation high-head hydropower systems in California. The unusual energy basis for reservoir modeling allows for development of hydropower operations models to estimate large-scale system behavior without the expense and time needed to develop traditional streamflow and reservoir volume-based models in absence of storage and release capacity, penstock head, and efficiency information. An Energy-Based Hydropower Optimization Model (EBHOM) is developed to facilitate a practical climate change study based on the historical generation data high-elevation hydropower plants in California. Employing recent historical hourly energy prices, energy generation in California is explored for three climate warming scenarios (dry warming, wet warming, and warming-only) over 14 years, representing a range of hydrologic conditions. Currently, the high-elevation hydropower plants in California have to renew their FERC licenses. A method based on cooperative game theory is developed to explore FERC relicensing process, in which dam owners negotiate over the available instream water with other interest groups downstream. It is discussed how the lack of incentive for cooperation results in long delay in FERC relicensing in practice and argued how climate change may provide an incentive for cooperation among the parties to hasten the relicensing. An "adaptive FERC license" framework is proposed, to improve the performance and adaptability of the system to future changes with no cost to the FERC, in face of uncertainty about future hydrological and ecological conditions.;Keywords. Hydropower, Climate Change, Energy-Based Optimization Model (EBHOM), No-Spill Method (NSM), Optimization, Modeling, Cooperative Game Theory, Conflict Resolution, Decision Support System (DSS), FERC, Licensing, California.