negative sides of hydropower in China
China indeed has enormous hydropower potential, especially in Southwest region, with many rivers high above sea level. Naturally China wants to exploit this potential and build new hydropower stations.
However there is unfortunately lot more negative sides of hydropower in China.
First of all, many people that live in southwest China and other locations with huge hydropower potential will be relocated and forced to abandon their households once these big installation projects take place. Good news is that Southwest China isn't that heavily populated as some other parts of China, but still lots of people will have to abandon their homes and many of them are already worried about their future.
For example, Dadu River that has the biggest hydropower potential capable of having 22 power plants installed in near future will cause relocation of more than 100,000 people once if this project starts. Some environmentalists and ecologists call this massive hydropower project as the second worst ecological disaster in China's history, comparable to terrific deforestation that was happening in period between the 50s and the 90s.
Water ways are not the same as they used to be since hydroelectric power plants altered their way. And this has destroyed many different ecosystems. This scenario should be expected in southwest China too.
China has many nature conservation areas but that isn't preventing them from building new hydroelectric power plants in these areas, despite of laws and different other regulations and this trend is mainly the result of increased energy demand. This problem has big, both economic and ecological impact. and China will have to choose whether to preserve this area as nature conservancies or to turn them into hydropower generator centers.
Man-made tunnels have also caused many rivers' drying up and water scarcity problem has become serious problem in many areas in China. And there are millions of people who are short of drinking water, since many of the last couple of years were poor with rains.
Water shortage problem could be a great problem for not only China's future, but also for current hydropower projects. With the rise of global warming problem, drought and water scarcity became more often than they used to be.
For example, water levels in country's longest river Yangtze are the lowest in history of recording it, and climate change that is already affecting China will also put in jeopardy China's massive hydroelectric projects. Hydropower, if it is not supplied with enough water, is worthless. And if water scarcity continues, China will again have to rely on coal or other fossil fuels to follow its rapid economic growth, which would result in totally missed hydropower projects, and be meaning more imported fossil fuel and even higher expenses.
Besides these problems above there is also the fear that hydropower projects would even worsen global warming effect, because of methane which is greenhouse gas even more powerful than the carbon dioxide because methane traps heat with significantly larger impact than carbon dioxide.
Problem regarding methane lies in the fact that methane is produced by plants and animals that rot underwater and once water goes through hydropower turbines, methane is released into atmosphere. Considering China's plan that includes doubling the amount of energy gained from hydropower this could mean significant increase in methane emissions, according to some experts of about 8 %. However certain methods allow capturing of this methane that could be later used for power generation, of course with proper design of dams which would stop methane reaching the atmosphere. Some estimations say 2.6 million tones could be collected from dams for additional power generation. It is also very important to prevent sewage from entering reservoirs and this is perhaps the biggest problem since China's sewage system isn't acceptable in many areas. Methane emissions are especially serious problem in shallow tropical reservoirs and luckily China's dams are mostly deep enough and in temperate zones.
However,some scientists are still worried about future projects. Some people like Chinese writer Dai Quing have been issuing the warnings about environmental damage and frequent landslides as the result of huge weight of water behind the dam and fluctuations in the water level that were caused by the largest Three Gorges dam and could continue in future projects as well.
