The Debate of the Dams: Are hydroelectricity plants worth the cost?

Photo by archer10 (Dennis) |

The installation of the final 700 megawatt turbine unit marked the end of an iconic engineering feat in the province of Hubei, China on July 4, 2012.  This concluded the construction of China’s Three Gorges Dam, situated along the Yangtze River, which supplies the planet’s largest source of hydroelectric power. 

Having commenced 16 years ago, the Three Gorges Dam project offered a promising source of renewable energy for years to come.  The premise behind a hydropower plant is to control the water flow of a river, via a dam or reservoir, through hydraulic turbines that are connected to a generator, feeding power to the electrical grid.  

This basic manipulation of the Earth’s water cycle has a bounty of benefits when we narrow in on its energy efficiency and ‘green’ factor within the scope of air quality.  With virtually no harmful emissions throughout the process of generating hydropower, the Three Gorges Dam has already saved nearly 200 million tonnes of coal per year in its lifetime! 

A great deal of politicians and scientists alike would agree this is a preferred alternative to fossil fuel consumption for energy production.  China definitely thought so, as the Three Gorges is now the source of 11% of the country’s hydroelectricity.

Just as the waters of the Yangtze River plunge into tunnels in the basin of the Three Gorges Dam, so begins the onslaught of environmental consequences brought on by altered river flow and expected flooding of the surrounding region….

The colossal concrete and steel structure imposes a direct physical barrier on wildlife of the species-rich district.  This ultimately causes habitat fragmentation, in which the region’s ecosystems are segregated into smaller sections due to impedance in the natural layout of the land.  This physical pressure upon plants and animals is particular significant in the Yangtze River since its basin is home to 361 various fish species.  The dam endangers this plethora of fish life by churning cold, oxygen poor water into the warm, O2-rich habitats that the fish thrive upon and are accustomed to in the basin.

Aside from the river’s role in ecosystem function, fish migrations are evidently obstructed by the dam as well.  It is no surprise that the changes in flow regime and water temperature throughout the Yangtze River Basin, coupled with the harm imposed by the dam as a physical obstacle, result in over a quarter of all freshwater fish endangerment in China.

Renewable sources of energy aren’t always feasible alternatives to the power plant methods of combusting fossil fuels and incinerating waste that receive a heightened amount of political attention for their greenhouse gas emissions impacts.  Direct blows to both biodiversity and indigenous communities of areas like the Yangtze River Basin or the Amazon are why hydroelectric dams are growingly criticized by informed and impacted citizens attempting to put the future of sustainable energy on a steadier course.