SPLTRAK Abstract Submission
Extraction of Prevailing Soiling Rates from Soiling Measurement Data 
Joshua Peterson, Julie Chard, Justin Robinson
GroundWork Renewables, Inc., Sand City, CA, United States

The accumulation of airborne particulate matter on PV module surfaces is referred to as soiling. Having a good understanding of the soiling rate at a site is of critical importance in the development stage of large-scale PV projects. GroundWork Renewables, Inc. (GroundWork) has deployed hundreds of soiling measurement kits to measure localized PV module soiling rates during preconstruction resource assessment. The soiling measurement kits employ a pair of matched PV modules. Soiling is measured by comparing the output current of the “soiled” module to that of the “clean” control module. Raw data from soiling measurement kits are often difficult to interpret due to inherent noise, incomplete or inconsistent cleaning events, and variations resulting from paired modules not being perfectly co-planar. GroundWork has developed a soiling data processing tool to analyze soiling measurement data. Monthly and annualized soiling rates are generated, along with their corresponding uncertainty. The presentation will describe key features of the data processing steps, the challenges associated with soiling rate calculations, and the methods used to overcome these challenges.