Controversies associated with hydroelectric power systems

Posted by Roderick Ellison - MSc BSc (Hons) AIEMA on 18/02/2011

Hydroelectric power is without doubt one of the oldest power generation methods available - it forms a key role in the production of electricity across the globe. Using energy captured from flowing water, it is estimated that hydroelectric power contributed 19% of the world’s power in 2006. It is still the most frequently used renewable energy source worldwide, offering benefits such as a lack of direct emissions or by-products into the environment, easy maintenance and low running costs.

The idea of using moving water to generate energy is certainly not a new one. For thousands of years, humans have used this kind of energy to power irrigation systems and flour mills. However, in recent times, the majority of hydroelectric power is generated from dams. As dams build up substantial reservoirs, they allow for a large amount of energy to be extracted. The water from the reservoir is forwarded to turbines located at the bottom of the dam, increasing the amount of energy that can be extracted from the water. The P = hrk formula (where P = the theoretical power generation, h = the maximum water height behind the dam, r = the flow rate of water into the turbines and k = the conversion factor that takes into account system efficiency, acceleration due to gravity, and the density of the water) is used to calculate the potential power levels from a dam.

However, the use of a dam to produce hydroelectric power is not without controversy. When a new dam is built, a location with a large enough reservoir is required, in order to maximise the potential energy that the water can provide. To create such a large depth, large areas of land are often flooded to create a reservoir. This can have a large impact on the people who are living on or nearby the land. In China, the Three Gorges Dam project in 2007 courted much controversy, due to the number of dwellers that had to be moved in order to create the new reservoir. The BBC reported that an estimated 4 million people would be relocated during the development of the dam. Additionally, many important archaeological or historical sites have since flooded as the water level rose.

The building of new hydroelectric dams can also have an impact on local wildlife, mainly by preventing fish from navigating the newly built dam. This issue alone has resulted in a significant reduction in the number of salmon existent in the Pacific Northwest region of North America. The fish rely on upstream swimming to reproduce on spawning grounds. However, the recent introduction of fish ladders has helped to reduce this decline in numbers.

However, even when taking into consideration the problems associated with the production of hydroelectric power, it still appears to be building in popularity. Certainly, in recent times, when environmental issues are at the forefront of our minds, and fuel costs are increasing, it could still lead the way as a non-reliant on fossil fuel alternative. 

Fortunately, despite these potential limitations, Ecosulis is able to help prospective developers overcome these issues and develop solutions that meet the needs of sustainable development. Contact our EIA team for further information.