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).
Climate strongly affects energy supply and demand in the Pacific Northwest (PNW) and Washington State (WA). We evaluate potential changes in the seasonality and annual amount of PNW hydropower production and changes in energy demand in a warming climate by linking simulated streamflow scenarios produced by a hydrology model to a simulation model of the Columbia River hydro system. Energy demand, and potential changes therein, are assessed estimates of heating degree days (HDD) and cooling degree days (CDD) for both the 20th century climate and projections of climate in three future periods (2010-2039, 2030-2059, and 2070-2099) and two emissions scenarios (IPCC A1B and B1). The gridded HDD and CDD values are then combined with population projections to create energy demand indices that respond both to climate, future population, and changes in air conditioning market penetration. We find that substantial changes in the amount and seasonality of energy supply and demand in the PNW are likely to occur over the next century in response to warming, precipitation changes, and population growth. In the 2020s, regional hydropower production increases by 0.5-4% in winter, decreases by 9-11% in summer, with annual reductions of 1-4%. Slightly larger increases in winter, and summer decreases, are projected for the 2040s and 2080s. In the absence of warming, population growth is projected to result in considerable increases in heating energy demand, however, the combined effects of warming and population growth are projected to result in net increases that are approximately one-half those associated with population growth alone. On the other hand, population growth combined with warming greatly increases the projected demand for cooling energy, notwithstanding that by the 2080s, total cooling energy requirements will still be substantially lower than heating energy demand.
Global climate models do not have sufficient spatial resolution to represent the atmospheric and land surface processes that determine the unique regional heterogeneity of the climate of the State of Washington. If future large-scale weather patterns interact differently with the local terrain and coastlines than current weather patterns, local changes in temperature and precipitation could be quite different from the coarse-scale changes projected by global models. Regional climate models explicitly simulate the interactions between the large-scale weather patterns simulated by a global model and the local terrain. We have performed two 100-year climate simulations using the Weather and Research Forecasting (WRF) model developed at the National Center for Atmospheric Research (NCAR). One simulation is forced by the NCAR Community Climate System Model version 3 (CCSM3) and the second is forced by a simulation of the Max Plank Institute, Hamburg, global model(ECHAM5). The mesoscale simulations produce regional changes in snow cover, cloudiness, and circulation patterns associated with interactions between the large-scale climate change and the regional topography and land-water contrasts. These changes substantially alter the temperature and precipitation trends over the region relative to the global model result or statistical down scaling. To illustrate this effect, we analyze the changes from the current climate (1970-1999) to the mid 21st century (2030-2059). Changes in seasonal-mean temperature, precipitation, and snowpack are presented. Several climatological indices of extreme daily weather are also presented: precipitation intensity, fraction of precipitation occurring in extreme daily events, heat wave frequency, growing season length, and frequency of warm nights. Despite somewhat different changes in seasonal precipitation and temperature from the two regional simulations, consistent results for changes in snowpack and extreme precipitation are found in both simulations.
A new generation of hydropower technologies, the kinetic hydro and wave energy conversion devices, offers the possibility of generating electricity from the movements of water, without the need for dams and diversions. The Energy Policy Act of 2005 encouraged the development of these sources of renewable energy in the United States, and there is growing interest in deploying them globally. The technologies that would extract electricity from free-flowing streams, estuaries, and oceans have not been widely tested. Consequently, the U.S. Department of Energy convened a workshop to (1) identify the varieties of hydrokinetic energy and wave energy conversion devices and their stages of development, (2) identify where these technologies can best operate, (3) identify the potential environmental issues associated with these technologies and possible mitigation measures, and (4) develop a list of research needs and/or practical solutions to address unresolved environmental issues. We review the results of that workshop, focusing on potential effects on freshwater, estuarine, and marine ecosystems, and we describe recent national and international developments.