In 2012, about 22% of the world's electricity was generated from renewable energy sources. Of that, about 77% came from hydropower. Between 2012 and 2040, the Energy Information Administration (in the IEO2016 Reference case) projects that about 33% of new renewable generation will be hydropower (in the IEO2013 Reference case, hydropower was projected to have over 50% of the generation growth). Despite this growth, the EIA projects that hydropower will drop to just over 50% of the total renewable energy generation in 2040. This drop in total percentage is very apparent in the chart below. (Note that the chart below uses the same data as the chart on the previous page, but is expressed as a percentage instead of total generation.)
In their 2016 "hydropower status report" (an outstanding resource for international hydropower trends!) the International Hydropower Association (IHA) reports that 33.7 GW of new hydropower capacity was installed in 2015. At the end of 2015, worldwide hydropower capacity was about 1,212 GW (up from 1,036 GW in 2014). China dwarfs all other countries in increased capacity, with nearly 20 GW of growth in 2015.
Types of Hydropower Plants
There are three general types of hydropower stations:
Run of River (or Diversion), electricity is generated through the flow of a river.
Reservoir (or Impoundment), water is stored in a reservoir where the release of the water to generate electricity can be controlled.
Pumped Storage, where stored water is pumped from a lower reservoir to a higher reservoir, so that it can be released to generate electricity when needed.
To Read Now
Visit the Office of Energy Efficiency and Renewable Energy (EERE) and read
How Hydropower Works Be sure to scroll over animation at top of page for more detail. Near bottom of page, click "Hydropower Basics page" and see a closeup of the turbine and generator. Again, scroll over for details.
After reading through the information on the link above, please watch the following (3:50) video from the U.S. Department of Energy.
To Read Now
Visit the Foundation for Water & Energy Education.
Take the Walk Through a Hydro Project tour, click through all 10 steps.
Take the Fish Passage tour, click through all 5 features (Spillways, Turbines, Juvenile Fish Transportation, Bypass Systems, Fish Ladders).
To Read Now
Read an article from Yale 360 that illustrates how pumped storage can be integrated with other renewable energy sources.
A fourth emerging type of hydropower is marine and hydrokinetic, where electricity is generated from the energy of waves, tides, ocean and river currents. Data are hard to come by, but in their 2013 Hydropower Report the International Hydropower Association estimates global installed tidal and ocean capacity was about 515 MW at the of 2012, with roughly an additional 3,000 MW of "pipeline capacity" (planned).