Saharan dust transport to Europe and its impact on photovoltaic performance: A case study of soiling in Portugal

The impact of long range Saharan dust transport, arising from one event in February and other in March 2017, on the performance of photovoltaic flat panels is reported as a case study of soiling. Through satellite images, dust coming from north Africa was detected, while using the Hybrid Single-Particle Lagrangian Integrated Trajectory, specific origin locations of the dust were found. Dust accumulated on glass coupons deployed in Southern Portugal, Évora and Alter do Chão, was analysed by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy. Mass accumulation on those coupons was weekly measured with a microbalance and related with environmental parameters, aerosol optical depth and rain, through a proposed empirical model. Performance measurement took place at Évora using mc-Si PV flat panels and an I-V curve tracer to get two parameters: maximum output power and short-circuit current. It was found that the first dust event led to decreases in the maximum output power of ≈8% and in the short-circuit current of ≈3%, while the second event led to a decrease of ≈3% in both parameters. A relation between PV performance and mass accumulation was successfully explored.