Hydroelectric power, also known as hydropower, is a form of renewable energy that utilises the water stored in dams to generate electricity. It is produced from generator-driven turbines that convert the energy from fast-flowing water or falling water into mechanical energy.
Typically, to generate hydropower, a dam is constructed on a big river with a high elevation. The dam stores the water behind it in a reservoir. An in-let is created to allow water entry into the dam; the force of gravity allows the water to flow into the dam. A turbine propeller at the distal end moves due to the pressure of the water entering the dam. The energy of the moving turbine powers the generator which produces the electric power. Power lines are connected to the generators to transport the electricity to the grid.
Hydropower is a significant component of global electricity production. About 17 per cent of the total electricity production in the world comes from hydropower (learn more). China is the largest producer of hydroelectricity, accompanied by Canada, Brazil and the United States.
Several merits accompany the use of hydropower which includes;
- It is a clean, renewable energy source and so there is no emission of greenhouse gases
- The water utilised in the process is freely provided, and unlike fuel and natural gas, it is not subject to market fluctuations.
- It has relatively low maintenance costs.
- No fuel is burned in the process, so there is minimal pollution.
Although hydropower does not pollute the environment, there are some downsides associated with it;
- It poses a threat to land use and natural habitats in the location.
- It is relatively expensive to construct a reservoir and a dam.
- Hydroelectricity is strongly dependent on precipitation levels; this can cause instability due to fluctuating water levels.
- It can also cause changes in river water quality, and these changes can affect native plants and animals in the river.