A hydropower facility consists of a plant for electricity production and a water reservoirformed by a darn in a river. The dam has gates that can open or close depending on howmuch water is needed to produce a certain amount of electricity. The electricity is transportedthrough transmission lines to an electric utility company.
Hydropower is very convenient because it can respond quickly to ﬂuctuations in demand.The production of hydroelectricity is increased on hot summer afternoons when power isneeded for air conditioners and decreased at night when people use less energy. The reservoirof water behind the darn is stored energy that can Support ﬁsheries and provide various formsof water—based recreation for local residents and tourists. Thus, hydropower reservoirscontribute to the local economy and quality of life.Hydroelectricity is “clean and green.” Once the system has been installed, the burning offossil fuels is not required to produce the electricity. Hydropower is good for the environmentbecause it does not release greenhouse gases into the atmosphere nor produce waste thatrequires special containment, as do other forms of energy production. After the water powersthe turbines, it simply returns unchanged to the water cycle.
Hydroelectric power is also very efficient and relatively inexpensive. The earth’s watercycle naturally replenishes the supply of “fuel” water. Wherever enough rain falls, there willbe rivers. If a particular section of river has the right terrain to form a reservoir, it may besuitable for dam construction. Modem hydroelectric turbines can convert as much as 90percent of the available energy into electricity. In contrast, the best fossil-fuel plants are onlyabout 50 percent efficient.
Summarize the points made in the lecture, being sure to explain how they contradict specific points made in the reading passage.