Albedo measurement: a novel estimation approach to enhance bifacial PV modules reliability

Enertis Applus+, with extended expertise in the renewable energy and energy storage sectors, investigated the variability of albedo, the percentage of radiation reflected by a surface, in short-term measurement campaigns and compared it with satellite measurements and onsite long-term measurements obtained from nearby meteorological stations. This study was carried out in collaboration with the Technological Institute for Microelectronics (TiM) of the University of the Basque Country (UPV/EHU) within the framework of an R&D project by the Center for the Development of Industrial Technology (CDTI).

Albedo is an essential input parameter for estimating the lifetime performance of bifacial PV modules, a factor that directly affects the profitability of photovoltaic (PV) projects.

Up to now, the reasons causing albedo variability were not well known, and it seemed to be partly random and due to several factors, such as changes on the surface due to its nonuniformity, seasonality and humidity. Results obtained in this study suggest that albedo variability is not completely random and that it increases considerably closer to the solstice in all measurement methods analysed.

As part of the study, Enertis Applus+ and TiM developed a statistical model comparing short-term measurement campaigns with long-term ones and satellite ones. This model defines the minimum number of required measurements for each surface or climate type to ensure that onsite short-term albedo matches with onsite long-term measurements with a previously defined admissible error. Therefore, this methodology allows us to optimise the duration of onsite measurement campaigns according to surface type and seasonality, providing more accurate data than satellite measurements.

The developed statistical model allows not only to determine the optimum measurement number and duration but also to provide clients with an admissible error and uncertainty factor, as well as the real degree of albedo variability depending on the time of year. This improves the accuracy and reliability of periodic, short-term albedo measurement campaigns as an alternative to satellite measurements with a lower spatial resolution and provides a more accurate estimate of a project’s production and profitability.

Contact us if you require further information. As part of our solar testing and solar inspection services, we offer albedo measurement campaigns along with other key services to ensure quality control and the long-term success of solar power plants.