Heliostat accurate control method robust under shading and blocking

Concentrated Solar Power [CSP] technologies address one of the challenges associated with intermittent energy sources such as wind and solar by incorporating thermal energy storage [TES], allowing generation to be shifted to periods without solar resources, and providing backup energy during periods with reduced sunlight that can be caused by cloud cover. Furthermore, CSP's ability to operate on gas when TES runs out offers a base load and dispatchable renewable solution in the systems that use a gas generator as a backup, which in the future can rely on hydrogen. Enhancing optical efficiency is a key challenge in CSP technology development, which requires wirelessly controlling the exact aiming orientation of tens of thousands of heliostats within sub-milliradian accuracy, while optically monitoring the field from outside the optical path where a very high temperature is obtained. Another challenge is the minimal number of pixels designated to each heliostat, as the entire solar field is monitored simultaneously. Optical efficiency optimization is also challenging due to the inherent tradeoff between the Ground Cover Ratio (GCR) and the shading and blocking of the mirrors. The heliostat control method proposed in this paper is applicable to solar power tower technology. This study aims to improve the accuracy of the solar field's tracking under shading and blocking by presenting and implementing a novel tracking method and comparing it to prior art. The method is based on monitoring the reflection from a specular curved bar along the vertical and the horizontal edge of the heliostat (or mirror facet). According to the place of the sun's reflection, the deviation from the receiver is obtained. The results show that the triangulation method using a specular curved bar gives an accuracy of 0.8 mrad, which is superior to the prior art, considering shading and blocking. It also provides the best accuracy in the exploitation of pixels. This enhancement in efficiency will bring us closer to achieving 90–95 % availability of renewable electricity at the cost of gas. This advancement stands as a significant stride in our ongoing battle against climate change.