China start work on world first solar thermal power plant

They call it the world’s first dual tower concentrated solar power plant and while the Chinese tend towards hyperbole when discussing their environmental work, it is certainly an impressive piece of infrastructure

Situated in the northwest of China’s Gansu Province, commissioning on the project has begun and it is expected to begin producing power by the end of this year. 

Its significant feature is that it will be able to provide consistent power output 24 hours a day with or without direct sunlight.

Whereas the solar panels we are used to seeing in fields and on roofs in the UK work by absorbing sunlight into PV cells within the panel, with solar thermal the panels are high quality mirrors (known as heliostats) which reflect the sun onto a receiver. In this case however, there are two receivers.

In the new Chinese project, there are 30,000 such mirrors, across an area of 800,000m², along with two receivers and a turbine generator.

Significantly, the mirrors move to follow the direction of sunlight and being of very high definition, can reach a reflection efficiency of 94%,  greatly improving the efficiency of power generation.

The heat absorbed by the two towers is transferred into two vast storage tanks filled with molten salt at 300 and 500 degrees Celsius respectively. The salt can store several times more heat than water and it can store that energy for weeks without significant losses. It is this stored heat that allows continuous and consistent power output for 24 hours.

Once up and running, the power station is expected to generate 1.8 billion kWh, cutting about 1.53 million tonnes of carbon dioxide emissions.

According to a report on China’s solar thermal power industry in 2023, the total installed capacity of the country’s solar thermal generating units reached 588 megawatts, accounting for 7.8 percent of the installed solar thermal capacity in the world.