How Is Hydroelectric Energy Stored?
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Juli 05, 2023
Introduction
Hydroelectric energy is a clean and renewable source of energy that is produced by converting the energy of flowing water into electricity. It is one of the oldest and most widely used forms of renewable energy, with hydroelectric power plants providing around 16% of the world's electricity. However, one of the challenges of using hydroelectric energy is storing the energy produced during times of excess generation to be used when demand is high. In this article, we will explore how hydroelectric energy is stored and the different methods used to do so.Hydroelectric Energy Storage Methods
There are several methods of storing hydroelectric energy, including pumped-storage hydroelectricity, compressed air energy storage (CAES), and thermal energy storage (TES).Pumped-Storage Hydroelectricity
Pumped-storage hydroelectricity is the most common method of storing hydroelectric energy. It involves using excess energy generated during times of low demand to pump water from a lower reservoir to a higher reservoir. When demand for electricity is high, the water is released back down to the lower reservoir, driving turbines to generate electricity. This method is highly efficient, with pumped-storage hydroelectricity plants able to convert up to 80% of the stored energy back into electricity. It is also the most flexible method of storing hydroelectric energy, as the amount of energy stored can be easily adjusted by changing the amount of water in the upper reservoir.Compressed Air Energy Storage (CAES)
CAES involves using excess energy generated by a hydroelectric power plant to compress air and store it in underground caverns. When demand for electricity is high, the compressed air is released and used to drive turbines to generate electricity. This method is less efficient than pumped-storage hydroelectricity, with only around 70% of the stored energy being converted back into electricity. However, it is more cost-effective than pumped-storage hydroelectricity and can be used in areas where there is no suitable topography for building a pumped-storage hydroelectricity plant.Thermal Energy Storage (TES)
TES is a method of storing hydroelectric energy that involves using excess energy to heat a thermal storage material, such as molten salt. When demand for electricity is high, the stored heat is used to generate steam, which drives turbines to generate electricity. This method is less efficient than pumped-storage hydroelectricity and CAES, with only around 50% of the stored energy being converted back into electricity. However, it is useful in areas where there is a high demand for both electricity and heat, such as in district heating systems.FAQs
Q: What is the most common method of storing hydroelectric energy?A: The most common method of storing hydroelectric energy is pumped-storage hydroelectricity. Q: How efficient is pumped-storage hydroelectricity?
A: Pumped-storage hydroelectricity plants can convert up to 80% of the stored energy back into electricity. Q: Where is CAES most commonly used?
A: CAES is commonly used in areas where there is no suitable topography for building a pumped-storage hydroelectricity plant. Q: What is TES used for?
A: TES is useful in areas where there is a high demand for both electricity and heat, such as in district heating systems.
Advantages and Disadvantages of Hydroelectric Energy Storage
Advantages:- Hydroelectric energy is renewable and clean
- Hydroelectric power plants have a long lifespan
- Hydroelectric energy storage helps to stabilize the grid and ensure a reliable supply of electricity
- Hydroelectric energy storage can be used in combination with other renewable energy sources to provide a consistent supply of electricity
Disadvantages:
- Building hydroelectric power plants can have environmental impacts, such as disrupting river ecosystems
- Hydroelectric power plants can be expensive to build
- Hydroelectric energy storage methods are location-dependent and may not be suitable for all areas
- Hydroelectric power plants may be affected by droughts and other climate events that reduce the supply of water needed to generate electricity
Conclusion
Hydroelectric energy is a valuable source of renewable energy that can be used to provide a consistent supply of electricity. Storing excess hydroelectric energy is an important challenge that has been addressed through the use of pumped-storage hydroelectricity, CAES, and TES. Each method has its own advantages and disadvantages, and the choice of which method to use depends on factors such as location, cost, and efficiency.Sources
- International Energy Agency. (2021). Hydropower. https://www.iea.org/reports/hydropower- U.S. Energy Information Administration. (2021). Hydroelectric power: How it works. https://www.eia.gov/energyexplained/hydropower/how-hydropower-works.php
- National Renewable Energy Laboratory. (2021). Energy storage. https://www.nrel.gov/storage/hydro-energy-storage.html
- Energy.gov. (2021). Energy storage. https://www.energy.gov/eere/electricity/energy-storage
- HydroWorld. (2021). Hydroelectric energy storage. https://www.hydroworld.com/hydroelectric-energy-storage/