By zhanqun1 
Amidst the vast and boundless deserts of northwestern China stands a colossal structure known as the “Super Mirror Power Station”—the 100 MW molten salt tower solar thermal power station in Dunhuang, Gansu. This awe-inspiring project, resembling a giant silver sunflower, embraces the blazing sun, converting every ray of sunlight into valuable electricity, providing thousands of households with a continuous supply of clean energy.
A Marvelous Engineering Feat
Designed, invested in, and constructed independently by a Chinese enterprise, this power station has been operating since its grid connection at the end of December 2018, becoming one of the country’s first batch of solar thermal demonstration projects. Spanning over 1.4 million square meters, with a total land area of 780 hectares, the station boasts an impressive annual power generation capacity of 390 million kWh. This translates to an annual reduction of approximately 350,000 tons of carbon dioxide emissions—an environmental benefit equivalent to afforesting 10,000 acres of land. As the world’s largest solar thermal power plant in terms of light-concentrating area and the highest heat-absorbing tower, it signifies China’s entry into the exclusive league of nations mastering 100 MW-scale solar thermal technology.
A Fairy-Tale Power Factory
Imagine having a magical garden filled with countless shimmering mirrors. But these aren’t just ordinary mirrors—they are intelligent heliostats, capable of rotating to follow the sun’s movement, ensuring that every ray of sunlight is precisely reflected onto a central tower. This towering structure is not a typical boiler but a heat collector known as the receiver tower.
The Fascinating Journey of Sunlight Turning into Electricity
When sunlight is reflected onto the receiver tower, something extraordinary happens. Inside the tower is a special “magic salt” known as molten salt. This salt melts into a liquid at high temperatures and can store an enormous amount of heat. As sunlight continuously heats the receiver tower, the molten salt inside reaches an astonishing temperature of 565°C (1,049°F).
Now comes the moment of transformation! The high-temperature molten salt flows through pipelines, much like hot water in a thermos. However, instead of directly generating steam, it heats water in another system, producing high-temperature, high-pressure steam. This steam then powers a turbine, which rapidly spins like a giant fan. The turbine, in turn, drives a generator, ultimately producing the electricity we use every day.
The Secret to Round-the-Clock Power Generation
But did you know? Even at night or on cloudy days when there is no sunlight, this super mirror power station continues generating electricity. This is thanks to a special energy storage system: the excess heat collected during the day is stored in a separate molten salt tank, which acts like a giant thermal battery. When needed, the stored heat is released to continue producing steam and electricity. This ingenious design ensures a stable power supply, making the station operational 24 hours a day.
A Gigantic Array of Heliostats
Covering a massive 7.8 square kilometers, the power station is home to more than 12,000 heliostats, arranged in concentric circles around the towering receiver. These intelligent mirrors, meticulously designed by engineers, automatically adjust their angles according to the sun’s movement, maximizing solar energy capture. As sunlight bathes the desert, the heliostats synchronize their reflections, directing millions of beams toward the receiver tower, completing the magical transformation from solar energy to electricity.
The Science Behind Molten Salt Storage
You might wonder—why is salt used in this power station? To withstand the harsh natural conditions of the region, including extreme temperature variations between day and night and frequent sandstorms, engineers innovatively adopted molten salt as the heat storage medium. Around 20,000 tons of molten salt continuously circulate between two tanks—one storing thermal energy and the other kept at a lower temperature. This system functions like an enormous rechargeable battery, allowing the station to generate power even at night or on cloudy days. With this clever setup, the power station not only achieves round-the-clock electricity production but also significantly improves energy efficiency.
Clean Energy Benefiting Thousands of Households
It is estimated that this molten salt tower solar thermal power station generates enough electricity annually to power approximately 200,000 households, alleviating electricity supply pressures in the Dunhuang region. At the same time, it significantly improves the surrounding environment by reducing greenhouse gas emissions, making an important contribution to ecological protection.
In conclusion, the 100 MW molten salt tower solar thermal power station in Dunhuang, Gansu is more than just a technological marvel—it is a milestone on humanity’s path toward sustainable development. By demonstrating the immense potential of clean energy, it instills hope for a greener and brighter future.