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Hydropower
Published in Robert Ehrlich, Harold A. Geller, John R. Cressman, Renewable Energy, 2023
Robert Ehrlich, Harold A. Geller, John R. Cressman
The manner in which small-scale hydro is produced varies. For example, some companies make compact combined turbine generators that can simply be submerged in a fast-flowing stream without having to build a dam or install any piping. One such UK-made device capable of producing 100 W looks very much like a half meter-long submarine (Figure 8.8). Although such a compact submersible turbine plus generator may be an elegant way to produce a small amount of power, it captures only a small fraction of the power of the stream based on the fraction of the stream cross section that encounters the turbine propeller. The more common way of harnessing nearly all the power of a stream is using a so-called run-of-the-river hydro, whereby the elevation drop of a river is used to generate electricity (Figure 8.9). It is common in this case to divert the bulk of the flow through pipes or a tunnel and then allow the water to return to the river after passing through a turbine. Many small run-of-the-river hydro projects have zero or minimal environmental impact because they do not require a large dam. This cannot be said for large-scale conventional hydropower, but the subject of environmental impact will be deferred until we have looked at the other ways waterpower can produce useful work or electricity.
Renewable & Alternative Power Technologies
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
While the famous massive hydropower plants draw the most attention, the majority of hydropower plants are much smaller. Many are similar in concept and design, but at a scale of one tenth or one hundredth the size. Projects of much smaller capacity and with rated heads of about 65 ft (20 m) or less are termed low-head plants. These can still be sizable systems of 20 MW or more, though many are under 1 MW of capacity. Low-head dams may often be located closer to where the real electric loads are, reducing the power lost in transmission. They may also be designed as run-of-the river plants, which use power in the river water as it passes through the plant without causing appreciable change in the river flow. These systems generally impound very little water and, in some cases, do not require a dam or reservoir. This reduces the likelihood of water quality changes, such as higher temperature, lower oxygen, increased phosphorus and nitrogen, and increased siltation.
Linking Microgrids with Renewable Generation
Published in Stephen A. Roosa, Fundamentals of Microgrids, 2020
Of the total solar energy incident on Earth, approximately 21% is used for maintaining the global water cycle of evaporation and precipitation. But only 0.02% of this amount of energy is available as kinetic and potential energy stored in the rivers and lakes of the Earth [8]. The water reserves are available in solid (ice), liquid (water), and gaseous (water vapor) conditions and are continuously cycled by incident solar energy. This global water cycle is mainly fed by evaporation of water from oceans, plants, and continental waters. The resulting precipitation which feeds snow fields, glaciers, streams, rivers, lakes, and groundwater is a source for small hydropower. Using low-head hydropower systems or flowing water (run of the river) to power electric turbines creates opportunities to generate power in close proximity to loads as many villages and towns are found near rivers and streams. Small hydropower plants are less than 30 MW in size. There are thousands of such sites in the U.S. with existing dams that are available for mini-hydropower applications. A small hydropower installation at the Kentucky River Lock and Dam No. 2 in Mercer County, Kentucky (the Mother Ann Lee hydroelectric plant) began operation in 2007 and provides power for the equivalent of 2,000 residences [9]. There are numerous recent international examples including the new 15 MW hydropower plant in the Soloman Islands.
Discussions on “Model studies for the design of inlet transition of settling basins of hydropower projects in high sediment yield areas: a review”
Published in ISH Journal of Hydraulic Engineering, 2022
The water wealth and terrain head of the Himalayas are nature’s gift and a bounty. Most of the hydro-power potential of India (1,48,701 MW) lies in the Himalayan region because the rivers in this region descend from an elevation of around 3,500 m to 500 m in a short distance of 200-km stretch. Majority of the hydropower plants (e.g. Naptha Jhakri) in these areas are run-of-the river type. High dams (e.g. Bhakra, Tehri etc.) with huge reservoirs are opposed these days due to environmental and other reasons. Apart from large volume of water, the Himalayan rivers like Indus, Ganga, Brahmaputra and their tributaries carry large quantity of sediments due to fragile nature of Himalayan rocks, avalanches, glacial lake outburst floods and landslides. The rivers in the Indian peninsula like Krishna and the Godavari carry sediments with concentration of about 100 p.p.m. only. Whereas concentration of the sediments carried by the rivers Indus, Ganga, Brahmaputra and their tributaries exceeds 2,000 p.p.m. Silt concentration of the Kosi river is more than 3,000 p.p.m. During severe floods, sediment concentration rises upto 5,000 p.p.m. or more.
Integrative technology hubs for urban food-energy-water nexuses and cost-benefit-risk tradeoffs (I): Global trend and technology metrics
Published in Critical Reviews in Environmental Science and Technology, 2021
Ni-Bin Chang, Uzzal Hossain, Andrea Valencia, Jiangxiao Qiu, Qipeng P. Zheng, Lixing Gu, Mengnan Chen, Jia-Wei Lu, Ana Pires, Chelsea Kaandorp, Edo Abraham, Marie-Claire ten Veldhuis, Nick van de Giesen, Bruno Molle, Severine Tomas, Nassim Ait-Mouheb, Deborah Dotta, Rémi Declercq, Martin Perrin, Léon Conradi, Geoffrey Molle
As a potential renewable energy, run-of-the-river hydroelectricity is a typical type of hydropower that harvests the energy from flowing water to generate electricity via an impoundment facility. However, tidal power can also convert kinetic hydro-energy into power. With the rapid advancement of this technology, tidal energy potential has been estimated to be about 32 PWh/year globally (Rusu & Venugopal, 2019). Due to its huge potential, the European Union has planned to install capacities of 3.6 GW and 188 GW by 2020 and 2050, respectively (Segura et al., 2017). Since tidal energy technologies are still in an initial stage of development, environmental impact, cost-benefit, technological viability, and potential risks are yet to be thoroughly studied, although some successful cases have been reported (Segura et al., 2017). Several technology variations have been reported to provide cost-effective energy generation (shown in Supplementary Information Table S4). Some of these technologies may be considered centralized technology. Descriptions of hydro-power technologies such as tidal barrage (T2-TB), dynamic tidal power (T3-DTP), stream generator (T1-SG) and wave energy to power (T4-WtP) are given in Supplementary Information (S1.1), and the associated costs, benefits, and risks are shown in Table S4 (Supplementary Information).
The role of hydropower in visions of water resources development for rivers of Western Nepal
Published in International Journal of Water Resources Development, 2021
Emily L. Pakhtigian, Marc Jeuland, Luna Bharati, Vishnu Prasad Pandey
From an energy perspective, the demand-driven local management approach prioritizes generation for local consumption. New small-to-medium-scale run-of-the-river schemes, many of which are already licensed, therefore become more attractive. The construction of these licensed projects would add substantial energy-generating capacity, which could be used to expand electricity access throughout Western Nepal (Sharma & Awal, 2013). In addition to having lower fixed construction costs, run-of-the-river projects are less environmentally disruptive and do not require inundation of inhabited or natural areas. These projects rely on natural river flows, however, and therefore would deliver less reliable power and water supply to consumers and irrigators, absent investment in complementary generating capacity (e.g. solar) or storage.