| HEP Project Bad for Environment?|
|China's Three Gorges Dam project must rank as one of the longest running construction projects of the last century and also one of the most controversial. As with any dam project, there are major criticisms as to the impact it is having on ecology and the displacement of people and wildlife. Add to this the difficulties of doing business in China, major variances in reported costs, and claims that the project has altered the way in which the world rotates(!) and you're left with a rather unique and interesting project.|
The dam was first conceived in 1919 and some preliminary surveying work was undertaken in 1944 when 54 Chinese engineers went to the US for training. Little happened after that until the idea re-emerged in the 1980s, approval was granted by the National People's Congress in 1993 and construction finally got underway in 1994.
By 2006, the dam body was complete and all the components that were originally planned were installed by the end of October 2008, when commercial operation began. A further six main generators are being added to the original 26 and are due to be operational in 2011. A ship lift is being installed in addition to ship locks and is due for completion in 2014. That will be a total of 95 years since its initial inception.
The dam is 2,335 metres (7,661 feet) long, 185 metres (607 feet) high and creates a reservoir that is 660 kilometres (410 miles) long, 1.12 kilometres (0.7 miles) wide on average and has a total surface area of 1,045 square kilometres. Around 102,600,000 cubic metres of earth were moved and the project has used 200,000 cubic metres of concrete and 463,000 tonnes of steel. The official cost of the project is $27.2 billion, which is below budget due to low inflation, although other estimates put the true cost at $88 billion.
The Three Gorges is the world's largest hydropower project, although the maximum reservoir capacity of 39.3 billion cubic metres ranks it only 22nd in the world. The project's 32 generators will have a total electricity generating capacity of 22.5 GW when fully operational. By September 2009, the dam was estimated to have generated 348.4 TWh of electricity, which is enough to recover over one third of the project's official cost (depending on which cost you use!).
Environmental and Social Criticisms...
Construction of the dam has caused the flooding of 632 square kilometres of land, resulting in the displacement of 1.3 million people as thirteen cities, 140 towns and 1,350 villages were submerged as well as 1,300 archaeological sites. This has added to the controversy that has always surrounded the dam, with one of the more sensational claims being that it will slow the earth's rotation.
Another rather dubious claim is that, since the dam sits on two major fault lines, it will increase the risk of earthquakes. This is refuted by the Chinese authorities who claim a reduction in seismic activity since its construction. Nevertheless, the more sensational claims should not divert attention from the serious threats to the local ecology and the environment.
The submerging of numerous mines, factories and waste dumps may well lead to increased pollution and there are reports of plumes of algae forming in the water. The project has been blamed for contributing to the extinction of the Yangtze River dolphin and threatening numerous other species.
The rise and fall of the reservoir's water level is causing erosion of the banks, resulting in landslides that add to the levels of silt in the water, which may eventually block the dam's sluice gates. The dam has also reduced the river's flushing power, which increases the risks of pollution. Reports of hairline cracks in the dam have raised doubts over its stability.
Balancing the Argument...
Ultimately the negatives will need to be weighted against the benefits. There is no doubt that the dam is generating electricity and reducing flooding. The Chinese authorities pointed out that the electricity produced by the project reduces coal consumption by 31 million tonnes a year and saves 100 million tonnes of greenhouse gas emissions. Improvements to shipping passage have increased barge traffic, with further savings in carbon dioxide emissions. The biggest advantage is obviously that the dam's capacity decreases the incidence of flooding, with the reservoir level being reduced from 175 to 145 metres prior to the flood season to allow for surges.
Despite the criticisms therefore, China is pressing ahead and has plans to build a network of dams that will provide additional power generation and reduce the level of sediment. Having gained expertise through these projects, it also plans to export its expertise and become involved in dam projects in other countries.