The world's first "dual-tower, single-unit" concentrated solar power (CSP) plant initiated trial operations on Thursday in the vast Gobi Desert in northwest China's Gansu Province.
Using an innovative two-tower design, the plant increases energy capture by nearly a quarter compared to conventional single-tower systems.
The solar thermal power plant has an installed capacity of 100,000 kilowatts. It will be a central part of Guazhou's 700,000-kilowatt project, which consists of a 400,000-kilowatt wind farm and a 200,000-kilowatt photovoltaic plant.
The entire project can generate 1.8 billion kilowatt-hours of clean energy annually, reducing carbon dioxide emissions by about 1.53 million tons.
From atop one of the absorber towers, standing over 200 meters tall, the scale of the facility becomes clear: two vast circular mirror arrays, each targeting its own central tower, with nearly 27,000 heliostats tracking the sun like a field of high-tech sunflowers.
What makes the system unique is its intelligent mirror coordination. Heliostats located in the overlapping area between the two mirror fields redirect sunlight to the east tower in the morning and the west tower in the afternoon, maximizing daily energy capture.
"Because of heavy dust and sand in the Gobi Desert, we need to regularly clean these mirrors, which are specially made of ultra-clear glass with 94-percent reflectivity. This ensures more efficient sunlight concentration on the towers, significantly boosting power generation," said project manager Yang Xuliang.
Inside the towers, a complex thermal exchange system is at work.
"This is the trace heating system preheating the pipes. The blue pipes carry salt at over 200 degrees Celsius from the cold salt tank up the tower, while the red pipes bring the heated salt, now over 600 degrees, back down to the tank below, forming a complete circulation system. It works like a traditional solar cooker, except we've replaced water with molten salt," explained Peng Shide, technical director of the project.
The captured energy is stored in two massive tanks containing molten salt, which boils at 600 degrees Celsius, far higher than water's 100 degrees, enabling much greater thermal storage capacity per unit volume.
"This molten salt thermal storage system has a maximum storage capacity equivalent to 600,000 kWh of electricity, enabling up to six hours of continuous power supply. It can not only be heated directly by sunlight but also, in theory, store excess power generated by wind and solar photovoltaic by converting it into thermal energy," said Li Zhenguo, deputy general manager of SunSum Technology, co-contractor of the project.
Compared with traditional single-tower CSP plants, the dual-tower configuration breaks through single-unit capacity limits while improving generation efficiency, total output, and storage capability, paving a new path for the large-scale development of solar thermal technology in China.
Innovative design enables world's first dual-tower solar thermal plant greater energy storage capacity
