- Study finds continuous galvanised steel offers superior resistance to wind driven sand erosion.
- Results challenge the assumption that harder coatings always perform better in desert solar plants.
- Findings have direct implications for PV projects across arid and semi-arid regions of Africa.
A research team led by Spain National Center for Metallurgical Research has delivered new insights into how photovoltaic mounting structures perform under harsh desert conditions, a growing concern for large scale solar projects across Africa.
Published in Solar Energy Materials and Solar Cells the paper entitled “Surface erosion damage in mounting structures of large-scale photovoltaic systems,” examines how different protective coatings used in PV mounting systems respond to sand erosion, one of the most aggressive and under studied degradation factors in desert and semi desert environments.
Utility scale solar plants rely on extensive metallic structures to support modules, tracking systems and drive components. While corrosion and panel degradation are widely documented, the impact of wind driven sand on these structures has received far less attention, despite its relevance in regions with frequent dust storms and high turbulence.
The researchers evaluated three widely used galvanised coatings for steel mounting systems. These included continuous galvanised steel known as Z275, a zinc magnesium aluminium alloy coating referred to as ZM310, and traditional hot dip galvanised steel. In addition, aluminium based motion components protected by an organic coating were also assessed.
To simulate real world desert conditions, the team applied two testing approaches. A free falling sand method and a forced air sand impingement method were used to measure surface degradation and erosion rates. The organic coating used on drive system components successfully met international abrasion resistance standards, confirming its suitability for external solar plant equipment.
Among the metallic coatings, continuous galvanised steel Z275 delivered the strongest performance, showing the lowest erosion rate across both testing methods. It outperformed both hot dip galvanised steel and the zinc aluminium magnesium alloy coating.
According to the researchers, the results demonstrate that higher hardness alone does not guarantee better erosion resistance. Instead, properties such as ductility, coating continuity and resistance to brittle failure play a decisive role in how coatings withstand repeated sand impacts over time.
The study also highlights the value of forced air sand testing as a practical alternative to traditional methods. This approach is faster, less physically demanding and allows for control of impact angles, sand velocity and mass flow, enabling more realistic simulation of operating conditions in desert environments.
These findings are particularly relevant for solar developers and engineers working in Africa, where many new utility scale PV projects are located in arid regions. Wind driven sand erosion can significantly affect the service life of mounting structures, especially as particle impact angles vary widely during dust storms and turbulent conditions.
By improving understanding of coating performance under erosion stress, the research provides valuable guidance for material selection, system design and long term reliability of solar plants operating in some of the continent most challenging environments.
Author: Bryan Groenendaal
