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Run-of-the-river hydroelectricity (ROR) is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amount of storage, in which case the storage reservoir is referred to as pondage. A plant without pondage has no water storage and is, therefore, subject to seasonal river flows. Thus, the plant will operate as an intermittent energy source while a plant with pondage can regulate the water flow at all times and can serve as a peaking power plant or base load power plant. == Concept == Run-of-the-river or ROR hydroelectricity is considered ideal for streams or rivers that can sustain a minimum flow or those regulated by a lake or reservoir upstream. A small dam is usually built to create a headpond ensuring that there is enough water entering the penstock pipes that lead to the turbines which are at a lower elevation.〔 Projects with pondage, as opposed to those without pondage, can store water for daily load demands.〔 In general, projects divert some or most of a river’s flow (up to 95% of mean annual discharge)〔Knight Piesold Consulting. ( Plutonic Hydro Inc. Bute Inlet Project. Summary of Project Intake and Turbine Parameters ). Knight Piesold Consulting.〕 through a pipe and/or tunnel leading to electricity-generating turbines, then return the water back to the river downstream.〔Douglas T, Broomhall P, Orr C. (2007). (Run-of-the-River Hydropower in BC: A Citizen’s Guide to Understanding Approvals, Impacts and Sustainability of Independent Power Projects ). Watershed Watch.〕 ROR projects are dramatically different in design and appearance from conventional hydroelectric projects. Traditional hydro dams store enormous quantities of water in reservoirs, sometimes flooding large tracts of land. In contrast, run-of-river projects do not have most of the disadvantages associated with dams and reservoirs, which is why they are often considered environmentally friendly.〔Hydromax Energy Limited. (Hydromax Energy Limited website ).〕 In Canada no large hydroelectric reservoir has been created since the 1980s. The use of the term "run-of-the-river" for power projects varies around the world. Some may consider a project ROR if power is produced with no water storage while limited storage is considered ROR by others. Developers may mislabel a project ROR to soothe public perception about its environmental or social effects. The Bureau of Indian Standards describes run-of-the-river hydroelectricity as:〔 A power station utilizing the run of the river flows for generation of power with sufficient pondage for supplying water for meeting diurnal or weekly fluctuations of demand. In such stations, the normal course of the river is not materially altered. Many of the larger ROR projects have been designed to a scale and generating capacity rivaling some traditional hydro dams.〔Plutonic Power (2008). (Revised Project Description for Bute Inlet Hydroelectric Project Requirements. P1 ). Plutonic Power.〕 For example, one 2006 proposal in British Columbia, Canada has been designed to generate 1027 megawatts capacity.〔Wilderness Committee. (Wilderness Committee Comments on the Draft Terms of Reference, Bute Inlet Hydroelectric Private Power Project. Letter to Kathy Eichenberger, Project Assistant Director. P1 ). Wilderness Committee.〕 Some run of the river projects are downstream of other dams and reservoirs. The run of the river project didn't build the reservoir, but does take advantage of the water supplied by it. An example would be the 1995, 1,436 MW La Grande-1 generating station, previous upstream dams and reservoirs are part of the 1980s James Bay Project. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Run-of-the-river hydroelectricity」の詳細全文を読む スポンサード リンク
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