Hydropower is renewable. Each year, rain and snow replenish the supply. It is the nation’s most abundant source of renewable energy.
Hydropower is efficient. Hydropower plants at dams convert about 90 percent of the energy in falling water into electrical energy. By comparison, fossil-fueled plants lose more than half of the energy content of their fuel as waste heat and gases.
Hydropower is clean. Hydropower produces no emissions. There are no gases or waste products that contribute to air pollution.
Hydropower is secure. Water from our rivers is largely a domestic resource that is not subject to disruptions from foreign suppliers, cost fluctuations in power markets, international political crises or transportation outages.
Hydropower is flexible. By adjusting the amount of water flowing through the dams, hydropower can be increased or decreased very quickly to meet changes in demand for power. This meets a fundamental requirement of all electric grids, which is that demand must exactly match supply at all times to keep the system stable.
Hydropower allows for the growth of other renewable resources. Hydropower is a great “back-up” for wind and solar power—for example it can be ramped up to meet demand when the wind is not blowing, and dialed down at times of high winds.
Hydropower is affordable. This is because the “fuel” – water – is free, which keeps operating costs low and protects against fluctuations in fuel prices. Over the years, the dams have consistently provided some of the nation’s most affordable electricity.