Perhaps the most important advantage of hydroelectric power is that it is a renewable resource. Unlike fossil fuels, as long as the sun continues to power our lakes, rivers and other bodies of water through the water cycle, we will not run out of flowing water to use for our energy needs. Furthermore, many hydroelectric power plants have accumulation reservoirs that can hold back water when the demand for electricity is low. This allows for the conservation of hydroelectricity that would otherwise be wasted.
Because river water is a domestic resource, it is not subject to the price fluctuations faced by other types of energy generation. This gives hydroelectricity a stable price. Furthermore, it is a stable and reliable source of power. For example, hydroelectric plants can release their accumulation reservoirs, when more power is needed. Due mainly to the renewability of the energy provided by flowing water, compared to coal plants, nuclear plants, and natural gas plants, hydroelectric plants constitute the cheapest way to produce electricity in the United States.
Unlike some other methods of power generation -- fossil fuels in particular -- hydroelectricity produce very small amounts of greenhouse gases. Moreover, since only 33% of the globally available hydroelectric power has been tapped, we are in a position to reduce greenhouse gases even more by replacing more harmful energy generation methods with hydroelectric methods. This characteristic of hydroelectric power also reduces the amount of pollutants in the air, thereby improving the quality of the air we breathe and reducing the frequency of acid rain.
Hydroelectric plants also contribute significantly to the development of communities. In addition to electricity, plant constructions bring highways, commerce and industry to the communities that harbor them. This creates jobs and develops the economy by increasing the overall quality of life in this communities. Furthermore, hydroelectric power avoids the pollution produced by the burning of fossil fuels as well as the problems associated with nuclear power, such as radiation leakages and the storage of nuclear waste