- Advantage # 1. Hydroelectric power’s major economic benefit over fossil fuel is that hydroelectric power is not connected to the cost of oil. Hydroelectric power does not use any fuel, so no fuel has to be bought and no fuel has to be imported from other countries.
- Advantage # 2. Hydroelectric power does not rely on burning fossil fuels, so there is much less production of carbon dioxide. Therefore, hydroelectric power has an extremely low impact on air pollution levels from its daily operation.
- Advantage # 3. When large dams are built across a river, the water is stored behind the dam. This stored water is called the reservoir. The flow of water in a reservoir is slower than it would be in a river. Reservoirs can be used to fish, boat, and to irrigate crops. So the reservoir provides services to people besides the generation of electricity.
- Disadvantage # 1. The reservoirs also have disadvantages. They stop the natural flow of the river. Several aquatic organisms need rapidly flowing water as their habitat. Dams reduce the populations of these organisms, such as salmon, and can lead to a species becoming threatened or endangered. In the Columbia River area of the U.S. Pacific Northwest, some 400 dams have been built to harness hydroelectric power. In this picture you see salmon swimming in one of the rivers that has been dammed.
- Disadvantage # 2. People and cultural relics are often displaced when large dams and reservoirs are built. At the Three Gorges Dam in China, for example, millions of people had to be relocated to make room for the power plant. Also, many important historical and cultural sites were flooded by the newly-formed reservoir. As you can see from this picture, the hydroelectric plant disturbs more than just the river—it also involved major disruption of the land around the dam.
- Disadvantage # 3. Imagine what would happen if a dam failed and all the water behind it came crashing out at once. Dam failure is rare, but it is a serious threat and a deadly one. More than 170,000 people were killed when a dam in southern China failed in 1975. Record rainfall levels put too much pressure on it.
