One of the new CSP projects being built by Three Gorges Renewables is a novel dual-tower design at Guazhou, in Gansu Province: Construction images below
Three Gorges Renewables is now building three of the 30 new Chinese CSP projects underway, the editor of CSP Focus, Mr. Sun in China previously told SolarPACES, and were advertising for bids in 2022. They are one of China’s biggest State-Owned enterprises, having built the largest renewable project in the world, Three Gorges Dam for pumped hydro electric power.
A multi-tower configuration with a single power block in concentrated solar power (CSP) is not unheard of at the research level globally, like this multi-tower/particles CSP concept from Germany, and recent papers from Spain and China assessing aspects of dual tower.
But Three Gorges Renewables will be the first in the world to actually put dual tower CSP to the test at full scale in a commercial project. As a 100 MW tower CSP project, the risk is of attenuation of solar flux from the furthest away heliostats encircling the tower receiver, resulting in reduced solar flux at the tower. This would reduce the solar thermal generation capacity at the turbine in the power block (How CSP works). So, having the smaller radius of a 50 MW solar field solves that issue of attenuation, and researchers have analyzed the trade-offs – in the extra cost of two towers, versus perfect optical effectiveness.
“The 100 MW configuration is “tower molten salt technology, with an installed capacity of 2×50MW, a dual-tower and one-unit configuration, supporting two heat-absorbing towers, one ultra-high voltage unit, one intermediate reheating, an 8-stage reheating (tentative), axial exhaust, and a direct air-cooled condensing steam turbine. The rated capacity of the steam turbine is 1×100MW, and it is planned to be connected to the grid and generate power by the end of December 2023.
The 700,000-kilowatt (700 MW) ‘Solar Thermal Energy +’ project in Guazhou, Gansu Province, of Three Gorges Hengji Energy Pulse is one of the first batch of large-scale base projects in China’s 14th Five-Year Plan.”
According to the news from Gansu Province on Phoenix Net, the construction personnel at the site of the 100MW tower molten salt energy storage solar thermal power generation project of the 700,000-kilowatt “Solar Thermal Energy +” project of Three Gorges Hengji Energy Pulse are working with full enthusiasm, racing against time and accelerating the project construction progress.
Currently, the foundations of the two heat-absorbing towers, main factory buildings, cold salt tanks, hot salt tanks, as well as the pre-site production administration building, production complex building, site fencing, and the assembly workshop for the heliostat mirror are under intense construction. The entire solar thermal field will consist of 26,964 heliostat mirrors and is planned to be completed by early June.” said Peng Shide, the person in charge of the 100MW solar thermal project at China Three Gorges New Energy Group in Guazhou.
The project is jointly built by Hengji Energy Pulse, a member unit of the Chinese National Solar Thermal Alliance, and the state-owned enterprise China Three Gorges New Energy Group. It has a total investment of approximately 4.93 billion yuan and will construct a 100MW solar thermal power generation + 200MW photovoltaic power generation + 400MW wind power generation facility.