Maximization of concentrated solar thermal (CST) technology performance and minimization of operational expenditures (OPEX) require considering not only the solar resource, but also other effects such as soiling. Dust accumulation modifies the optical properties of solar collectors and mirror surfaces leading to a significative reduction of the useful solar energy. Current research points out that soiling can decrease specular reflectance by about 10% per month in low-soiling regime regions and higher than 40% in locations with high atmospheric aerosol loads, such as deserts. Thus, soiling stands out as one of the most impactful factors to be considered when assessing CST performance and corresponding OPEX. Nonetheless, soiling assessment is still performed in CST manually by operators using portable reflectometers, which is a time-consuming task. Besides, automatic instruments, such as the Tracking Cleanliness Sensor (TraCS) or the AVUS Instrument, only do spatial punctual measurements, which means that for bigger solar fields and for a precise soiling assessment, multiple ones have to be installed, increasing the capital expenditures (CAPEX). Additionally, there is no current instrumentation to measure soiling effect in Fresnel secondary optics or Stirling dishes, due to their height and size.

Therefore, the development of new techniques is needed to automatize and generalize soiling assessment for all CST technologies, while simultaneously making it faster and able to measure a greater number of units. In this project, a novel technique using a 3D laser scanner will be developed and tested at real solar fields, such as the one at IMDEA Energy in Spain, and at the Cyprus Institute. Measurements will be compared with reflectometer data aiming to establish a model with an absolute reflectance error lower than 2%. Some preliminary tests have been already performed at IMDEA Energy, showing promising results.

Partners: IMDEA Energy Institute (Coordinator) (Spain); The Cyprus Institute (Cyprus); Fraunhofer Institute for Solar Energy Systems ISE (Germany)

Funding Institution/Program: EU-SOLARIS

Call: EU-SOLARIS – Internal Project Proposals 2023

Type of action: Research and Innovation

Period: February 2024 – July 2025

IMDEA Energy Institute external funding: 16.000,00 €

Principal Investigator: Dr. Ricardo Conceição