Solar power plants in the form of solar concentrators – systems of many mirrors and focusing points of solar rays – have been created all over the world for more than 40 years. They can be either single or consist of several towers with their own fields of mirrors. In China, they are creating a unique solution – a double-tower solar concentrator with a cross arrangement of mirrors, which promises to increase the efficiency of the installation by 24%.
Image source: CGTN
Created in 2014 in the American Mojave Desert, the largest solar concentrator in the world at that time is represented by a complex of three towers, each of which is surrounded by its own field of concentrically placed mirrors. The power it produces reaches 392 MW. The Chinese installation in Gansu province will consist of two 200-meter towers, but the concentric fields of mirrors of each of them will intersect. This is a feature of the project – the mirrors in the intersection zone will serve both one and the second tower, directing sunlight to the concentrator of one and the other installation in the most optimal way for each time of day.
As in other similar concentrators, molten salts are supplied to the focusing zone of the mirrors at the tops of the towers. This will allow concentrated thermal energy to be stored even at night, directing it to generate steam and generate electricity throughout the day, even after sunset. Each year, the Chinese installation will be able to produce up to 1.8 GWh of electrical energy, providing a buffer for local energy production from traditional renewable sources – from the Sun and wind.
«Mirrors in the overlap area can be used by any tower, the developers explain. “This configuration is expected to improve efficiency by 24%.” The increased efficiency is also helped by the fact that the mirrors used have a 94 percent reflective efficiency, meaning that most of the solar energy that hits them is directed back to the power-generating towers. In total, the station will use reflection from 30 thousand mirrors. The installation is 90% complete and will be put into operation by the end of 2024.