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| Fig. 1: This is an image of the Three Gorges Dam in China. (Source: Wikimedia Commons) |
In late September of 1882 in the small city of Appleton, Wisconsin, the world saw its first hydroelectric power plant in operation. This plant created enough power to provide light to his home and the plant. Even though this was a huge milestone, the use of hydropower can be traced back to Ancient cultures to perform simple activities like grinding wheat. Now hydropower is the most important renewable source of energy. Contributing to 16% of total electricity production. [1] There are more than 57,000 large hydroelectric plants worldwide. [1] The Three Gorges Dam in China (Fig. 1) is the worlds largest hydroelectric power plant standing at 181 meters tall and 2,335 meters long with generating capacity of 22,500 megawatts.
There are four major components to conventional hydroelectric plants. The dam, turbine, generator, and transmission lines. [2] As shown in Fig. 2. all components work together as one to produce a massive amount of energy. The dam serves as the control of water flow. [2] It raises the water level of the river creating falling water. This creates a reservoir and thus stores energy. As falling water pushes against the turbine blades it begins to spin. Acting much like a windmill. Thus, the turbine successful turns the kinetic energy of the falling water into mechanical energy. [2] The turbine is connected to the generator by shafts or gears. As the turbine spins so does the generator. This converts the mechanical energy from the turbine to electrical energy. Finally, transmission lines serve as the conductor of electricity from the plant to buildings. [2] The concept of a hydropower plant is not extremely difficult to understand.
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| Fig. 2: This is a flow chart of the components and process of the an hydroelectric power plant. (Source: Wikimedia Commons) |
The use of hydropower has many advantages over other energy sources. First, fuel is not burned. Burning fuel from plants creates a lot of pollution and poor air quality in surrounding areas. [3] Along with this it reduces the greenhouse gas emissions to our atmosphere. Secondly, water is free and renewable. [3] Water is provided by nature, so there is no big cost to make the hydropower plant operate. The only cost is operations and maintenance, and those are still relatively low. Rainfall renews the water in the reservoir, so this fuel is always there. Lastly, this technology is reliable. As mentioned before, the hydropower has been used since ancient times. It has remained one the most reliable sources of energy since then.
Even though this reliable energy sources comes with its share of advantages, it still is not perfect. The first disadvantage that is commonly complained about is the cause of displacement of local populations. [4] In some areas, the building of a massive hydropower plant causes the local residences to move. Secondly, there can be a big environmental consequence because of the change of water flow and construction of roads and power-lines. [4] The construction may affect water quality of the streams and reservoir. Also, the change in water level effects fish habitats in the area because of shelter and food access. Finally, there is a dependency on nature to cooperate. If there is a drought or lack of significant rainfall, there is a loss of your fuel source. So obviously, to have an effective power plant there is a need to have nature cooperate.
Hydropower plants are a vital energy source to the world. Water is an efficient and reliable fuel. The use, creation, and expansion of power plants should continue being pursued.
© Malik Antoine. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] M. Konar et al., "Water Resources Sustainability in a Globalizing World: Who Uses the Water?," Hydrol. Process. 30, 3330 (2016).
[2] R. Deb, "Operating Hydroelectric Plants and Pumped Storage Units in a Competitive Environment," Electriciy J. 13, 24 (2000).
[3] M. Vinson , "Long-Term Dynamics of an Invertebrate Assemblage Downstream From a Large Dam," Ecol. Appl. 11, 711 (2001).
[4] C. P. Barros and N. Peypoch, "The Determinants of Cost Efficiency of Hydroelectric Generating Plants: A Random Frontier Approach," Energy Policy 35, 4463 (2007).
