With turbines that are the hardest, the deepest and the world’s most powerful, China’s new Baihetan Dam on the Yunnan-Sichuan border does a fine line in generating superlatives, as well as electricity.
Entering into initial service at the end of last month, a few days ahead of the Communist Party’s main centenary celebrations, the dam will have total installed capacity of 16 million kilowatts when all of its turbines are working next year. This makes it the world’s second most powerful hydroelectric dam after the Three Gorges Dam in Hubei province.
The new dam is the largest, and technically most difficult, bit of infrastructure in the West-East Electricity Transfer project, which is designed to tackle energy shortages in urban and industrial areas in the east coast with power generated in inland provinces, where wind and hydro power plants are concentrated. A construction boom over the past 50 years has seen five of the world’s 10 largest dams built in China. Coming with a Rmb220 billion ($34 billion) construction cost, Baihetan is likely to be the last of the country’s mega dams.
In fact, there are very few natural sites left in China that allow for such large-scale power generation after Baihetan, which sits on the Jinsha River. At the same time, other forms of renewable energy are becoming cheaper and more efficient. Future hydropower projects in China are likely to be smaller in scale and rely on so-called pumped storage technology, where water is recycled between an upper and lower reservoir. That’s good news for populations that live in areas designated for dam construction: some 50,000 people were relocated to make way for Baihetan, for instance.
The impressive know-how Chinese companies have developed in the construction of the Three Gorges and Baihetan dams can be added to China’s arsenal of infrastructure technology available for export, along with 5G networks and high-speed trains.
According to the Global Times the construction of the new dam also demonstrates the advantages of China’s system of government. Baihetan, which was built in just four years, “fully reflects China’s strong organisational and mobilisational capabilities, and fully proves the institutional advantages of socialism with Chinese characteristics,” the nationalistic newspaper wrote.
So just what is so impressive about Baihetan given it isn’t the largest in term of overall generating capacity? Well, for a start the geology of the site is tricky – the walls of the V-shaped canyon are made of dry, crumbly rock that is prone to shifting and breaking.
In addition, the gorge is narrow and the rock walls are not symmetrical, meaning the 289-metre high dam-wall cannot be either. In engineering terms this is a challenge because it means water pressure can’t be spread more evenly over the arch of the wall, as ideally would be the case. The area is prone to seismic activity as well – so the dam has been built in the knowledge that it will need to be constantly monitored and “repaired”.
Lastly, the narrowness of the gorge meant there was very little space for the turbines and other machinery – forcing the engineers to dig large caverns in the valley walls. Those underground chambers are the largest of any hydroelectric plant in the world and the network of passageways running inside the mountains next to the dam are the longest of their kind too.
But the most impressive technological feat are the 16 turbines. Each has an output capacity of one gigawatt, which is the most powerful ever per unit. When all 16 become operational in 2022, the dam will generate 62 billion kilowatt hours of electricity a year, helping to reduce China’s carbon emissions by 51 million tonnes annually. This will bring the country a step closer to Chinese President Xi Jinping’s goal of achieving carbon neutrality by 2060.
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