Hydroelectric
Water power (or hydropower) currently provides 16% of the world’s electricity.44 Since hydropower relies on moving water to provide energy to turbines, power plants, dams and other energy-harnessing equipment must be located at or near water sources. Most of the hydroelectric plants or dams on land harness energy from rain runoff as it travels from high altitudes to sea-level in rivers and other waterways. Other sources of hydropower include waves at the shore and tidal currents.
In addition to being a renewable source of energy, hydropower has other advantages. Most hydroelectricity has low operating costs, particularly compared to other renewables. The potential supply of energy from water is vast. Typically, the infrastructure for hydropower serves multiple uses; in addition to turbine-driven electricity production, many sites feature agricultural irrigation, flood control, navigational optimization and even water recreation. CO2 emissions from hydropower are very low, and it is widely available geographically.45 All of these benefits have led to hydropower being one of the most widely utilized of all of the renewable energy resources.
Despite the number of advantages realized from harnessing energy from water, there are multiple challenges to expanding hydroelectric energy. Dams are a major component of the world’s hydropower infrastructure, but they have increasingly come under fire due to their impact on the environment and on many communities of people who have been dispersed. In altering the natural flow of water and creating reservoirs or lakes, dams have caused the destruction or disruption of entire species and ecosystems. They have also led to the loss of culturally or anthropologically important sites. Many countries have established laws or policies that prevent or limit new dam construction.46
In addition to the negative ecological and social effects of dams, hydropower includes other drawbacks. Gathering energy from tides out in the ocean requires exposing expensive equipment to extremely stressful and damaging natural conditions. Hydropower is also vulnerable to climate change as the future behavior and nature of the oceans and land-based water are unpredictable.47
Comments: