The world's first 'twin towers and one machine' solar thermal energy storage power station
The commissioning of the west tower of the solar thermal energy storage power station has been successfully completed
On October 1, the world's first "two towers and one unit" solar thermal energy storage power plant entered the final commissioning stage, which is about to test run the whole system.
This power station consists of two 200 meter high heat absorbing towers and nearly 27000 solar mirrors. After successful system debugging, it can achieve 24-hour uninterrupted power supply.
Each sun setting mirror is like a sunflower chasing the light: in the morning, when the sun is set to the east, the mirror faces east to send light to the East Tower; In the afternoon, as the sun sets westward, they immediately turn their heads to serve the West Tower, ensuring that the sunlight does not run empty at both ends.
Twin Towers and One Machine: China's Innovation and Energy Revolution in Solar Thermal Energy Storage
In October 2025, the world's first "twin tower, one unit" solar thermal energy storage power station entered full system trial operation in Guazhou, Gansu. Two 200 meter high heat absorbing towers were lit up simultaneously on the Gobi Desert, marking China's breakthrough in the traditional "single tower, single machine" paradigm in the field of solar thermal power generation and opening up a new path for the utilization of new energy. This innovative project, created by Three Gorges Hengji Energy, is not only the core project of the national "Shagehuang" large base, but also redefines the commercial future of solar thermal energy storage with unique technological design.
The core innovation of "Twin Towers and One Machine" lies in the configuration of "two heat absorbing towers+one set of steam turbine generator units". At the project site, nearly 27000 heliostats form a circular mirror field with overlapping east and west parts, with a total lighting area of 800000 square meters, equivalent to the size of 112 football fields. These mirrors, made of special ultra white glass, have a reflection efficiency of 94% and can track the trajectory of the sun in real time. The overlapping area of the heliostats guides sunlight to the east tower in the morning and turns to the west tower in the afternoon, achieving efficient heat collection throughout the day through dynamic focusing technology. Compared with traditional single tower power stations, this design improves the optical efficiency of the mirror field by about 24%, extends the daily effective power generation time from 8 hours to over 12 hours, and increases the annual power generation by nearly 50%.
The molten salt energy storage system is the key to achieving 24-hour power supply in power plants. The heat absorption tower converts solar energy into high-temperature heat energy at 565 ℃, which is stored in specially designed molten salt. This domestically developed molten salt formula in China has a temperature resistance of 570 ℃, far exceeding the international mainstream standard of 500 ℃, and has a lower freezing point, avoiding pipeline blockage in winter. The cost is reduced by 40% compared to imported products. The entire thermal storage system can store thermal energy that can meet the 6-hour full load power generation of a 100000 kilowatt unit. When the power grid needs it, high-temperature molten salt generates steam through the heat exchange system to drive the operation of the steam turbine generator unit, with fast response speed and stable output power. The circulation system composed of red and blue pipes inside the tower is like the blood vessels of an "artificial sun". It sends 200 ℃ cold molten salt to the top of the tower for heating, and then sends 600 ℃ high-temperature molten salt back to the storage tank to complete energy storage and conversion.
As the core of the 700000 kW "Solar Thermal Energy Storage+" project, this power station forms a multi energy complementary system with 400000 kW wind power and 200000 kW photovoltaic power. In the case of unstable wind and photovoltaic power output, solar thermal energy storage can quickly release heat energy to fill the power supply gap and ensure stable grid frequency. After the project is put into operation, it is expected to provide 1.8 billion kilowatt hours of clean electricity per year, equivalent to the annual electricity consumption of 600000 households, reduce carbon dioxide emissions by about 1.53 million tons, and lower the cost of electricity to 0.35 yuan per kilowatt hour, approaching the level of coal-fired power. This will move solar thermal energy storage from a demonstration project to a replicable business model.
From the topping out of the twin towers in 2023 to the full system trial operation in 2025, the project has overcome multiple "bottleneck" technologies such as high-precision driving of the heliostat and high-temperature resistant coating of the heat absorbing tower, achieving the localization of core equipment. In the future, Guazhou will also pilot the "three towers and one machine" and "four towers and one machine" models to further improve the utilization rate of the mirror field. This "energy lighthouse" standing on the Gobi Desert not only proves the regulatory value of solar thermal energy storage in new energy bases, but also provides a low-cost and high-efficiency Chinese solution for global energy transformation.
