Freezing Cold Risk to Hydropower Infrastructure

Hydropower dams on the Tibetan plateau will be inefficient or inoperable because of freezing temperatures and power lines will wreck the region's natural beauty and exacerbate climate changes, warns geologist Yang Yong

On November 23 Tibet's first largehydropower plantat Zangmu went into operation, sparking huge concern in the Indian media. The new plant marks the start of large-scale hydropower generation in Tibet.

The dam at Zangmu stands 116 metres high at 3,310 meters above sea level. It has a reservoir capacity of 86.6 million cubic metres of water and a generating capacity of 510 megawatts. The project itself will not have a large impact on the local ecology or hydrology, but a single dam is unlikely to be profitable - a cascade of dams will be needed, passing water downstream in coordination with each other. Such large scale development will inevitably threaten the rivers of Tibet and the entire Plateau. If this approach is not changed the rivers of the Qinghai-Tibet Plateau face disaster.

During the 13th Five-year plan large hydropower dams will be developed on the Jinsha (upper Yantgtze), Lancang (Mekong), Nu (Salween) andYarlung Tsangpo, creating the highest density dam cluster in the world.

It is not known exactly how many hydroelectric plants Tibet already has, but there are less than 10 larger ones (50 megawatts or more) and over a hundred smaller ones. These are often inefficient and short-lived. Most of the hydroelectric plants I have studied at an altitude of 3,500 metres or more in Sichuan, Qinghai and Tibet suffer from ice blockages during the five months or so of freezing temperatures every year, meaning little or no electricity is generated. The cold weather also damages equipment and greatly increases maintenance costs.

Tibet is not suited to large-scale hydropower development for two reasons. First, the Qinghai-Tibet Plateau is the source of Asia's major rivers, and these are mostly fed by glacier meltwater, rather than precipitation. This means flows are highly seasonal and changeable and so power supply is unstable and the frozen winters and iced-up rivers can damage generating equipment.

Second, due to the quality of land in Tibet's river valleys and the geological conditions, creating reservoirs to regulate water flow is problematic. This reduces the ability of dams to regulate power generation and respond to higher demand. These two factors make development of hydropower in Tibet more technically and economically challenging.

Source: Thethirdpole.net

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• Environment Evaluation
• Dams
• Design & Construction
• Hydrology