California’s hydropower system is composed of high and low elevation power plants. There are more than 150 high-elevation power plants, at elevations above 1,000 feet (300 m). Most have modest reservoir storage capacities, but supply roughly 74% of California’s in-state hydropower. The expected shift of runoff peak from spring to winter due to climate warming, resulting in snowpack reduction and increased snowmelt, might have important effects on power generation and revenues in California. The large storage capacities at low-elevation power plants provide flexibility to operations of these units under climate warming. However, with climate warming, the adaptability of the high-elevation hydropower system is in question as this system was designed to take advantage of snowpack, a natural reservoir.With so many high-elevation hydropower plants in California, estimation of climate warming effects by conventional simulation or optimization methods would be tedious and expensive. An Energy-Based Hydropower Optimization Model (EBHOM) was developed to facilitate practical climate change and other low-resolution system-wide hydropower studies, based on the historical generation data of 137 high-elevation hydropower plants for which the data were complete for 14 years. Employing recent historical hourly energy prices, the model was used to explore energy generation in California for three climate warming scenarios (dry warming, wet warming, and warming-only) over 14 years, representing a range of hydrologic conditions. The system is sensitive to the quantity and timing of inflows. While dry warming and warming-only climate changes reduce average hydropower revenues, wet warming could increase revenue. Re-operation of available storage and generation capacities help compensate for snowpack losses to some extent. Storage capacity expansion and to a lesser extent generation capacity expansion both increase revenues, although such expansions might not be cost-effective.
Hydropower dams play a critical role in the health of river ecosystems throughout the United States, and hundreds of these dams will be relicensed by the Federal Energy Regulatory Commission (FERC) in the coming years. Such licenses lock in the operating and environmental protection requirements of such dams for periods of up to 50 years. Given the complex, dynamic nature of river ecosystems, as well as the impacts of climate change, there is pervasive scientific uncertainty about how to best manage dams for power production while protecting and enhancing environmental values such as water quality and fisheries. Unless dams are managed adaptively, with licenses that provide pathways for gathering and applying new knowledge and responding to changing conditions, we run the risk of locking in mistaken approaches and stymieing environmental improvements on our rivers for the next half century.
Introduction:FERC’s Integrated Licensing Process (ILP) is applicable to both relicensing existing hydroelectric projects and developing new projects. FERC’s ILP was developed during a period when there were few applications being filed for new projects. Although applications for relicensings may likely continue to outnumber applications for new projects, the complexity and number of new projects being pursued into licensing has increased significantly in the past two years. New projects today include conventional small and medium-sized hydroelectric projects. Many are multiple use water and energy projects, which can be bundled with pumped storage and transmission. There are also growing numbers of new hydroelectric based technologies such as tidal and wave energy projects that require licensing and often multiple agency approvals.
This paper presents an overview and some of the key points of the 2009 Assessment of Waterpower Potential and Development Needs Report prepared by EPRI and can be found on their website www.epri.com. The assessment projects the amount of additional waterpower capacity that could be developed in the U.S. under conservative and aggressive scenarios. The middle ground or likely scenario is that with increased levels of research support and incentive programs, the U. S. can develop an additional 39,750 MW of waterpower capacity from existing conventional hydroelectric facilities and emerging waterpower technologies that access the energy potential of river, tidal, constructed waterway currents and the energy of ocean waves and thermal gradients.Existing conventional hydropower generation represents 70 percent of the U.S. renewable energy generation (over 248,312 GWH) and the opportunity exists to expand this resource. The potential for waterpower expansion, at existing hydroelectric facilities, at dams without powerhouses, and from the emerging next generation of waterpower technologies, represents a substantial increase to the nation’s renewable domestic power supply. The 2007 estimate for waterpower that could be developed by 2025 exceeds the total wind capacity brought on line over the past 30 years (20,152 MW).