Shuangjiangkou Dam in Sichuan - the tallest dam under construction in the world uses heliostats to work in frost

High in the Sichuan Mountains, at an altitude of approximately 2,200 meters above sea level, a monumental hydrotechnical project is being built - the Shuangjiangkou Dam. Its planned height is as much as 315 meters, which makes it the highest dam under construction in the world. For comparison, the current record holder, the Jinping-I Dam, measures 305 meters. If everything goes according to plan, the Chinese structure will surpass it by another 10 meters.

Building this colossus is a huge engineering challenge. The dam is being built in a narrow mountain valley, where winter temperatures drop to as low as -20 degrees Celsius. Such harsh climatic conditions constitute a serious obstacle to construction works, especially when erecting the clay core of the dam.

The sun is at the service of engineers

The biggest innovation at the Shuangjiangkou construction site is the use of heliostats - special mirrors that track the movement of the sun and direct its rays exactly where they are needed most. A total of 27 such devices were installed. Their job is to focus light on the construction area to raise the temperature of the dam's clay core.

Why is it so important? The material from which the core is made must be placed and compacted under strictly controlled conditions. When the temperature drops below freezing, it becomes virtually impossible to achieve the required density. Previously, work could only be carried out for just over half a year. Thanks to the use of heliostats, which raise the temperature by about 3 degrees Celsius, engineers gain up to three additional hours of work every day, when conditions allow it.

While three degrees Celsius may seem like a small difference, it's a real game-changer on a construction site. Each additional hour of work allows you to arrange and compact subsequent layers of material faster, which translates into a real acceleration of work progress. In the case of such a gigantic structure, where over 45 million cubic meters of filling material are needed, every hour is worth its weight in gold.

Powerful energy and impressive numbers

Shuangjiangkou is not only about record heights. The dam will be equipped with four generators, each with a capacity of 500 megawatts. The total power of the plant will reach an impressive 2,000 MW. The first unit was already connected to the grid in June 2026, and once all four units are operational, the plant is expected to produce approximately 7.7 billion kilowatt hours of energy per year.