Located in Guazhou County of northwest China’s Gansu Province, a novel dual tower/ dual solar field concentrated solar power (CSP) plant has started commissioning and testing and is expected to officially generate power by the end of this year, said its operator, the China Three Gorges Corporation, on Monday.
The Three Gorges CSP project has two 50 MW towers, two 50 MW solar fields, and each feed their captured solar energy into a single 100 MW power block.
Three Gorges is the world’s biggest renewable energy firm, having built the largest renewable project in the world, China’s 22.5 GW Three Gorges Dam which harnesses pumped hydro electric power.
An issue with tower CSP at its now standardized scale of 100 MW is that at that scale, optical attenuation from the farthest heliostats surrounding the tower receiver can result in less than optimal solar flux at the tower and, consequently, lower solar thermal generation capacity at the turbine in the power block.
So instead of designing a typical 100 MW CSP project comprising one tower surrounded by one solar field, Three Gorges has pioneered a two tower/two solar field design by combining two smaller 50 MW towers, each with a smaller 50 MW solar field radius, so the attenuation issue is mitigated. The cost/benefit of the additional cost of two towers and achieving perfect optical efficiency has been analyzed by solar researchers, and this smaller dual tower design will put that theory to the test.
(Although the Ivanpah project in the Mojave Desert also has multiple towers with corresponding solar fields, each of these is a full scale CSP project and each has a full scale solar field and its own power block for a combined 377 MW.)
