Hydroelectric energy is in laymen's terms what it sounds like, energy produced from water--specifically moving water. Currently, hydroelectricity is by far the most popular form of renewable energy, and supplies between 15-20% of the world's electricity. Generally,
hydroelectric power comes from the potential energy of dammed water. The dammed water drives a water turbine and generator, which then converts the power into electricity. There are other methods of producing energy from the movement water though, including harnessing power from the tides, and using the current in rivers to produce power. For more info on tidal energy, click
here for a related article.
Hydroelectricity is most commonly produced with the use of dams, however. Especially in areas where there are large flowing rivers and lakes to draw water from. For this reason, places like British Columbia, Canada, with large, intricate waterway systems take full advantage of this type of power. Not only do they power residential areas, but they can also serve to power energy-intensive industries like aluminum smelting and other industrial activities.
Cleanliness = Godliness
Hydroelectricity is also fairly clean. Although fossil fuel is consumed in the construction of the dam, there is little to no carbon emissions beyond the dams initial construction in non-tropical regions. The same is not true for tropical regions, however, as
hydroelectric power plants have been observed to produce large amounts of methane and carbon dioxide if the surrounding forest is not cleared.
This is due to the fact that plant-life decays in the flooded areas at an alarming rate, producing methane, as well as smaller amounts of carbon dioxide. As is also reiterated below, placement is key when it comes to constructing a hydroelectric dam.
The Drawbacks : Disrupting the Ecosystem
Unfortunately, hydroelectricity is definitely not without its problems. Planning for hydroelectric projects often overlooks the damage to aquatic habitats and ecosystems and also to the surrounding
indigenous communities, who may have to relocate when a dam is built due to flooding in their communities.
This type of callousness is what quickly becomes problematic with dams. Planners have to be especially careful when diverting riverways in order to prevent any harsh long term effects on those that depend on the water, whether human or animal, and also to conserve historical monuments and other sites of cultural significance.
For instance, while dams can be used to prevent flooding when water levels rise beyond normal levels, in the area around Burns Lake, British Columbia, Canada, an entire village was forced to relocate due to flooding from the construction of a dam.
"Not only were the Cheslatta tribe forced to move, but their entire graveyard, relatives and all, was swept away with the current."
As you can see, while there are definite environmental benefits to hydroelectricity, there are many risks associated with diverting natural waterways. In order for hydro electricity to become truly viable and risk-free, we must first assess these risks and try our best to prevent similar incidents.
Source(s): Windsor, J. E, McVey, J. A. "Annihilation of both place and sense of place: the experience of the Cheslatta T' En
Canadian First Nation within the context of large-scale environmental projects." Geographical Journal; Jun2005, Vol. 171 Issue 2, pg. 146-165.