Hydroelectric power plants are the first and easiest electricity generation technology. The process of generating electricity from flowing water is known as hydroelectric power.
The water is usually controlled to fall from a higher elevation making turbines to rotate which is connected to a generator which in turn produces electricity. They are renewable sources of energy and the emission of greenhouse gases is very rare in the case of hydropower power plants however, it may cause a threat to the environment and community.
Post Content - In Short
- Pros and Cons of Hydroelectricity
- Advantages of Hydropower
- Disadvantages of Hydropower
Pros and Cons of Hydroelectricity
Hydroelectric power share with the world’s electricity consumption in 2006 was 20%. They are the cheapest and oldest method to produce electricity making it a competitive source of renewable energy. Hydroelectricity technologies are broadly divided into four categories-
- Pumped Storage,
- Run of the River and
- Offshore Marine(tidal).
The hydroelectric power comprises almost one-sixth of the world’s electricity generation, with an estimated 31.5 GW of capacity being put into operation in 2016. China accounts for almost one-third of global hydropower capacity followed by the US, Brazil, Canada, India, Japan and Russia which occupies 60% of the installed capacity at the end of 2016.
Advantages of Hydropower
– Pros of Hydroelectric Power or Hydroelectricity
1. Renewable Energy Source
Hydroelectric energy is renewable energy as energy is produced from running water. The energy source water is abundant on the earth’s surface that cannot be used up. Through the evaporation and condensation process, there is continuous rainfall on mother earth. Rivers and lakes are renewable energy sources for generating hydroelectricity.
As a result of drought and lower water levels, the amount of electricity that hydropower generates may vary but it is seasonal. On the other hand, fossil fuels such as coal and gas are limited and are not going to generate electricity when they are completely used up. Hydropower is the largest renewable energy source for electricity in the United States of America.
2. Clean energy source
Hydroelectric power plants are clean energy sources as they do not produce greenhouse gases or toxins that will pollute the environment. Actually dams constructed for the purpose of hydropower can be used for irrigation, entertainment, the habitation of aquatic life, etc. Hydropower comprises 96% of the renewable energy source in the world. Unlike other power plants such as fossil fuels, coal and nuclear it does not pollute the land, water, and air.
Hydroelectric power is one of the “green and “clean” alternative energy sources in the world although construction of large dams accounts for some level of pollution.
3. An inexpensive source of energy
Hydroelectric power is a cost-competitive source of energy even though the initial building costs can be high. River water and lakes are infinite sources of water that power the hydropower plants. Unlike fossil fuels or natural gas where market fluctuation plays a vital role, water is a domestic resource.
They provide a continuous supply of power for a considerably long period of time. Dams designed for long-term use have an average lifetime of 50 – 100 years meaning they are strategic investments that can support many future generations.
Hydroelectric power plants have low operating and maintenance costs since they need few replacements and comprise a lesser number of parts. The energy cost for hydropower in the US is just $0.08 per KW-hr whereas coal and other fuels cost $0.07 – $.14 per KW-hr.
4. Rural Communities are highly influenced by Hydropower
Hydropower power plants open the door for many opportunities such as the construction of roads, industry, and commerce. The manpower needed for such projects is from the communities itself which increases the economic condition of the locals and nation as a whole. This increases the quality of life of residents.
Hydropower not only produces the energy it also creates a good irrigation system, recreational activities, and habitat for aquatic life. Locals from the affected area can earn money from running a business, growing crops with irrigation facility and many more. Education and healthcare become more accessible than before due to the construction of highways.
5. It provides recreational opportunities
The construction of hydropower plants requires large dams that can be used for recreational activities such as boating, swimming, fishing, camping and water sports for holidaymakers. Water reservoirs create by hydroelectric power plants are major attractions for tourists as well.
6. Flexible Source of Energy
Hydropower is a dispatchable resource as it can generate electricity when needed. This means hydropower can be used to generate electricity 24/7. It can be scaled up and down quickly, that makes hydropower flexible sources of energy to meet the changing energy demands. The start-up time taken by hydro turbines is very less compared to gas turbines or steam plants.
7. A Reliable Source of Energy
Hydroelectric power plants are a reliable source of energy. Most of the countries of the world depend upon hydropower for energy sources. They are considered as a baseload energy source. They represent the best option to produce electricity that current technology supports. There is no or little fluctuation in the output rate or frequency of the power created unless a different output is desired.
8. Very Efficient
Hydropower plants are very efficient in the case of energy conversion. The conversion rate is approximately 90% that means 90 per cent of the captured energy is converted to electrical power. But in the case of wind and solar the conversion rate is about 59% and15% respectively.
Disadvantages of Hydropower
– Cons of Hydroelectric Power or Hydroelectricity
1. Causes environmental damage
Dams constructed for the purpose of hydropower plants have a large impact on the environment and ecosystem. They block the normal flow of rivers causing draught and possess a threat to aquatic life. Especially fishes and other creatures generally migrate in search of food and for breeding purposes which is greatly influenced by the blockage of water flow.
Though hydropower is a nonpolluting source of energy they have environmental impacts. They can affect the use of land, settlements and natural habitats in the construction site. They may use people’s homes, natural areas, agricultural land, and archaeological sites. According to researchers plants, material in flooded areas begin to rot and decompose in an anaerobic environment which releases substantial amounts of carbon dioxide and methane increasing pollution levels. In Egypt, some villages were moved more than 100 kilometres away from their generational homes.
2. Expensive Construction Cost
Hydropower plants require a lot of money and time to build. As the time required is maximum the cost also rises. They require dams and reservoirs for the purpose of generating electricity which requires a large investment. The turbines used for the also plants are also expensive. They are costly to construct due to logistical challenges like topography, laying foundations underwater and the material used to build it.
Due to large investment, there are only 300 hydropower plants in the world right now. The Itaipu Dam on the border of Paraguay and Brazil required installation cost of more than $20 billion and it took almost 20 years to build it.
3. May Cause Border Conflicts
Many states and countries of the world have borders based on rivers. Due to constructions of large dams, the flow of water is altered as a result draught is observed in some areas. This can trigger conflicts if the issue is not mutually solved
4. Draught may affect Hydropower plants
Due to the risk of local draught, hydropower plants are greatly affected. During the drought season, the water level in reservoirs decreases resulting in an inadequate supply of power. The income and expenses are calculated in advance for profit-making purpose and if local draught occurs it may lead to a loss.
The aquatic life is also in great danger because of drought and vegetation around the area are also affected. This may cause an imbalance in the ecological system leading to unfavourable climatic conditions.
5. Risk of flood in low altitude areas
The constructed dam for the purpose of generating electricity poses a threat to locals living downstream. After years of construction, the structure may collapse destroying the communities with the flood to follow.