Dear Editor, Criticism of the apparent cost of energy produced by the Three Gorges dam (IWP&DC April 2002, p2 ) overlooks the fact that the Chinese consider that it is a multi-purpose project. Visitors are told that its main functions are flood mitigation and water supply. It will reduce the intensity of flooding which has recently affected the cities and cultivated areas downstream of the dam, and will provide an additional source of water to be transferred to the northern cities, including Beijing, where there is a water shortage.
Additional benefits are improvements to river navigation which will allow larger ships and barges to reach Chongqing than can do so at present, and the provision of storage capacity for extra irrigation water in times of drought and for control of salinity at the river mouth.
To make an estimate of the cost of producing energy as a return on capital it would be more accurate to identify just the marginal capital costs for building the power station and transmission lines, and more accurate still, if a benefit price could be put on the national reduction in CO2 emissions by using hydro power instead of the equivalent electrical output from coal fired power stations.
As global climate change is a global matter we should be encouraging China to build more hydroelectric power stations.