Topic
Hydroelectricity
About: Hydroelectricity is a research topic. Over the lifetime, 4026 publications have been published within this topic receiving 47167 citations. The topic is also known as: hydroelectric power.
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TL;DR: In this article, major new initiatives in hydropower development are now under way, and at least 3,700 major dams, each with a capacity of more than 1MW, are either planned or under construction, primarily in countries with emerging economies.
Abstract: Human population growth, economic development, climate change, and the need to close the electricity access gap have stimulated the search for new sources of renewable energy. In response to this need, major new initiatives in hydropower development are now under way. At least 3,700 major dams, each with a capacity of more than 1 MW, are either planned or under construction, primarily in countries with emerging economies. These dams are predicted to increase the present global hydroelectricity capacity by 73 % to about 1,700 GW. Even such a dramatic expansion in hydropower capacity will be insufficient to compensate for the increasing electricity demand. Furthermore, it will only partially close the electricity gap, may not substantially reduce greenhouse gas emission (carbon dioxide and methane), and may not erase interdependencies and social conflicts. At the same time, it is certain to reduce the number of our planet’s remaining free-flowing large rivers by about 21 %. Clearly, there is an urgent need to evaluate and to mitigate the social, economic, and ecological ramifications of the current boom in global dam construction.
1,462 citations
TL;DR: A review of the current methods and advances in wind power forecasting and prediction can be found in this article, where numerical wind power prediction methods from global to local scales, ensemble forecasting, upscaling and downscaling processes are discussed.
1,017 citations
TL;DR: The earliest dams were probably constructed by blocking the stream with earth as discussed by the authors, and these dams were held in place by their own weight pressing against their foundations, and usually have a long sloping downstream toe to prevent overtipping.
Abstract: Most of the primary civilizations of the world emerged in or near river valleys. The construction of dams and other hydraulic structures is, therefore, one of the oldest branches of engineering (e.g. 11, 105). The earliest dams were probably built for the purposes of irrigation, flood control, and water supply. Later, water was impounded so that its subsequent controlled release could provide a source of energy, first by the use of waterwheels and later by the use of hydroelectric generators. Other purposes include the maintenance of an adequate river flow through the year for navigation, and the provision of facilities for recreation. Most modem reservoirs are designed for two or more of these purposes. Usually "the role of water storage reservoirs . . . is to impound water in periods of higher flows so that it may be released gradually during periods of lower flows" (135), but sometimes the sole purpose of the impoundment is to provide a new body of standing water for use as such; for example, for fishing or boating, or for waste-heat dissipation from a thermoelectric generating plant. The earliest dams were probably constructed by blocking the stream with earth. Such dams are still constructed. In its simplest form. an earth-fill dam is a pile of compacted earth extending across a stream with a fairly gentle slope both upstream and downstream. Similar to earth-fill dams are rock-fill dams composed of quarried rock or natural boulders or gravel with a layer of impervious material on the upstream face. A later development in dam construction was the invention of the masonry dam, probably in Spain (150). The earliest masonry dams were of the gravity type. Such dams are held in place by their own weight pressing against their foundations, and usually have a long sloping downstream toe to prevent overtipping.
815 citations
TL;DR: In this paper, the authors simulate the California electricity market after deregulation as a static Cournot market with a competitive fringe, and show that there is potential for significant market power in high demand hours, particularly in the fall and early winter months when hydroelectric output is at its lowest level relative to demand.
Abstract: Using historical cost data, we simulate the California electricity market after deregulation as a static Cournot market with a competitive fringe. Our model indicates that, under the pre-deregulation structure of generation ownership, there is potential for significant market power in high demand hours, particularly in the fall and early winter months when hydroelectric output is at its lowest level relative to demand. The results also show that two of the most important factors in determining the extent and severity of market power are the level of available hydroelectric production and the elasticity of demand.
586 citations
TL;DR: In this paper, a critical review of 167 case studies involving the life cycle assessment (LCA) of electricity generation based on hard coal, lignite, natural gas, oil, nuclear, biomass, hydroelectric, solar photovoltaic (PV) and wind was carried out to identify ranges of emission data for GHG, NOx and SO2 related to individual technologies.
Abstract: Electricity generation is a key contributor to global emissions of greenhouse gases (GHG), NOx and SO2 and their related environmental impact. A critical review of 167 case studies involving the life cycle assessment (LCA) of electricity generation based on hard coal, lignite, natural gas, oil, nuclear, biomass, hydroelectric, solar photovoltaic (PV) and wind was carried out to identify ranges of emission data for GHG, NOx and SO2 related to individual technologies. It was shown that GHG emissions could not be used as a single indicator to represent the environmental performance of a system or technology. Emission data were evaluated with respect to three life cycle phases (fuel provision, plant operation, and infrastructure). Direct emissions from plant operation represented the majority of the life cycle emissions for fossil fuel technologies, whereas fuel provision represented the largest contribution for biomass technologies (71% for GHG, 54% for NOx and 61% for SO2) and nuclear power (60% for GHG, 82% for NOx and 92% for SO2); infrastructures provided the highest impact for renewables. These data indicated that all three phases should be included for completeness and to avoid problem shifting. The most critical methodological aspects in relation to LCA studies were identified as follows: definition of the functional unit, the LCA method employed (e.g., IOA, PCA and hybrid), the emission allocation principle and/or system boundary expansion. The most important technological aspects were identified as follows: the energy recovery efficiency and the flue gas cleaning system for fossil fuel technologies; the electricity mix used during both the manufacturing and the construction phases for nuclear and renewable technologies; and the type, quality and origin of feedstock, as well as the amount and type of co-products, for biomass-based systems. This review demonstrates that the variability of existing LCA results for electricity generation can give rise to conflicting decisions regarding the environmental consequences of implementing new technologies.
563 citations