What is Hydropower?
Hydropower, also known as hydroelectricity, is the use of down- or fast-flowing water to generate electricity or power machinery. Hydropower is energy produced from moving water, such as rivers. This is achieved by converting the gravitational potential or kinetic energy of the water source to produce energy.
Renewable Energy
Hydropower is a renewable energy source. This means that using dams or rivers to generate electricity does not use up any finite resources such as coal or gasoline.
How do we get power from Water?
Water that falls into or flows from a large river has a lot of energy. We can exploit this by forcing water to flow through a pipe called a pressure hose. As water flows through the pipe, it rotates the turbine blades, which turn the generator. As long as the water flows, the generator will be able to provide electricity.
Engineers design hydroelectric plants in three main ways:
Storage System – Storage system using dams. The dam slows the flow of the river and stores water in the lake. Part of the water is discharged into the river at the bottom of the dam. The water falls and the water pressure from the lake pushes the water over the dam and spins the turbines that generate electricity. Dams are expensive to build, but they also help control flooding, can create a large recreational lake, and can provide fresh water to surrounding towns.
Run-of-the-river System – In a flow system, the turbines are driven by the natural flow of the river. These systems have the advantage of not creating a huge lake and flooding the area above the dam. As a result, they have less overall impact on the environment. However, in order to provide uninterrupted electricity, the river they use must be full all year round, as the flow is not regulated by a dam.
Pumped Storage System – This system is like a storage system except it uses a pump to pump the wastewater into the tank. The way it works is that at night when the electricity is much less, it uses the excess electricity to pump water to the top of the dam and fill the reservoir. This improves the overall efficiency of the hydroelectric plant.
History of Hydropower
Using rivers to power mechanical devices is not a new concept. As early as ancient times, thousands of years ago, humans used hydroelectricity to perform tasks such as grinding grain into flour. In the late 1800s, scientists first discovered how to use hydroelectricity to generate electricity.
The first hydroelectric power station was built in Wisconsin in 1882. Since then, many other power plants have been built in the United States, including the Hoover Dam in 1936 and the Grand Coulee Dam in 1942.
What are the Drawbacks to Hydropower?
Like any energy source, hydroelectricity has certain disadvantages. One disadvantage is the loss of land and damage to the local ecosystem caused when the lake is created by a dam. It can also force people to move and leave their homes. Another disadvantage is the methane emissions generated by the reservoirs. Dams and turbines can also injure fish and impede their migration to spawning grounds.
Fun Facts about Hydropower
There are more than 2,000 hydroelectric power plants in the United States.
Many countries, such as Norway and Brazil, derive a significant portion of their electricity (up to 85%) from hydroelectricity.
The largest dam and hydroelectric power plant in the world is the Three Gorges Dam in China. It delivers 22,500 megawatts of power!
Most dams in the United States are not built to provide electricity. They were built to control flooding and provide local irrigation water.