A durable and scalable anti-soiling coating for solar modules

The UK is committed to achieve net zero carbon emissions by 2050. This will require a massive shift in the way electricity is generated, away from burning fossil fuels and towards the use of renewable sources such as wind and solar. The cost of solar modules has reduced dramatically over the past few years and subsidy-free deployment is expanding rapidly, especially at utility scale. It is forecast that more than 40GW will be in use in the UK by 2030. Solar assets are financed by professional managers who are concerned by the ongoing operational costs of maintenance that affect power output and the return on investment. In particular, attention is being drawn to the problem of cover glass soiling that attenuates the light into the module. Soiling can reduce power output by up to 5% in the UK and is a far more serious problem (up to 50%) in arid sunbelt regions such as occur in India and the Middle East. Polymer-based hydrophobic anti-soiling coatings have been shown to work in principle, but their durability is not sufficient to withstand 24/7 exposure to environmental stresses or to abrasion damage caused by regular cleaning. The objective of this research is to develop and test a thin inorganic rare-earth oxide coating for application to solar cover glass. The hydrophobic coating will be low surface energy to reduce the adhesion to soiling. Its application will reduce the frequency of costly cleaning cycles. The coating will be capable of being applied at industrial scale using an Atmospheric Chemical Vapour Deposition process that is compatible with glass manufacturing. Use of the coating will significantly improve the practical power output of solar modules and will have worldwide impact.