In-Situ Solar Tower Power Plant Optimization by Differentiable Ray Tracing

Abstract

Solar tower power plants play a key role to facilitate the ongoing energy transition as they deliver climate neutral electricity and direct heat for chemical processes. These plants generate temperatures over 1000 °C by reflecting sunlight with thousands of mirrors (heliostats) to a receiver. The temper- ature achievable in practice is limited due to the system’s susceptibility to small surface defects and misalignments of individual mirrors, hindering the plant’s full efficiency. We present an inverse render- ing technique that predicts the incident power distribution of each heliostat, including the inaccuracies, based solely on focal spot images that are already acquired in most solar power plants. The method allows reconstructing flawed mirror shapes within sub-mm precision. Applied at the solar tower plant in Juelich, our approach outperforms all alternatives in accuracy and reliability. Our data-driven method is a key ingredient to building digital twins of solar power plants. It can be integrated into the existing infrastructure and plant control at low cost, leading to increased efficiency of existing and decreased expenses for future power plants, the key factors of success in the competitive market. For other fields, our approach can be a blueprint, as we present the option for the very first large-scale indus- trial deployment of differentiable ray tracing. Merging data-intensive Machine Learning with physical modeling creates flexible, data-efficient and trustworthy solutions applicable in science and industry.

In-Situ UNet-Based Heliostat Beam Characterization Method for Precise Flux Calculation Using the Camera-Target Method

“…The ux data obtained through our approach are readily applicable to superposition methods, like the one outlined by Rodríguez-Sánchez et al [6], enabling the direct calculation of the cumulative ux density from all heliostats. Additionally, this data can facilitate the extraction of surface information for individual heliostats, enhancing raytracing simulations as detailed in Pargmann et al [8].…”

“…In response to these limitations, more recent approaches by Rodríguez-Sánchez et al [6] and Pargmann et al [8] have been proposed. These methods leverage target images to derive more accurate ux predictions for individual heliostats.…”

“…Recent studies indicate that improved aimpoint strategies could signicantly boost annual revenue, exemplied by projections of up to a 39% increase for facilities like Gemasolar in Almeria [4]. Given that total irradiance is a superposition of individual contributions from each heliostat, each with its unique focal spot,there is a growing research focus on utilizing target images for precise predictions of single heliostat focal spots [5,6,7,8]. However, current camera-based ux calculation methods are hampered by limitations.…”