Hydroelectricity is the process of generating energy from the force of falling or flowing water.
How Does Hydroelectricity Work?
Hydroelectricity is generated using a dam system that makes water fall or move faster. Similar to wind energy, hydroelectricity uses a turbine to generate electricity. However, instead of using wind to turn the turbine, the motion of the water turns the turbine. This turbine spins a generator, which converts the energy to electrical energy. The amount of energy produced from one hydro plant changes based on the quantity and speed of the moving water. Some plants have systems that, during the night, use the electricity that was not used to pump extra water to the top of the dam to generate extra electricity in the morning. This process is called pumped storage.
How is this Renewable, Clean Energy?
This is clean energy due to the fact that the turbine and generator are powered completely by the movement of the water. Therefore, there are no greenhouse gases released into the atmosphere from hydroelectricity.
This may seem like it will not be renewable energy, but really, the water is just MOVING the turbines. Therefore, it is not using water. In fact, the pumped storage system explained earlier can be reusing the water that has already gone through. Therefore, this energy system is very renewable.
The Negative Impacts of Hydroelectricity on the Environment
While it is clear that hydroelectricity helps combat climate change, it still poses problems to the ecosystem. Blocking rivers with dams can degrade water quality, damage aquatic and amphibian habitat, block migratory fish passage, and displace local communities. This all has overall negative effects on the river ecosystem and biodiversity. Reservoirs may cover people's homes, important natural areas, agricultural land, and archeological sites. So building dams can require relocating people. Methane, a strong greenhouse gas, may also form in some reservoirs and be emitted to the atmosphere. However, this methane production israre but is still a concern.
The Presence of Hydroelectric Dams in America and the Rest of the World
Hydroelectricity generates 71% of all renewable energy generated in the world, and it generates 16.4% of the total world energy. As of 2017, it generates 44% of the renewable energy in America and 7% of all of America's energy. America is also the second largest producer of hydroelectricity in the world (second only to Canada).
New Zealand uses hydroelectricity for 99% of their energy production, and New Zealand uses it for 75% of their energy production!
28 million residents in the U.S. get their energy via hydroelectricity
Hydroelectricity prevents the burning of 22 billion gallons of oil or 120 million tons of coal each year