California-based PV testing lab PV Evolution Labs (PVEL) has introduced a new system for measuring power and energy loss due to module soiling in the field.
Soiling is the accumulation of dirt on PV modules, which can reduce annual energy output of a plant by up to 10% depending on the site location. Rather than guess about the level of soiling occurring, PVEL said its customers can now be certain about the performance of an existing site, or the expected performance at a proposed site.
Measuring soiling is gaining attention because, as solar assets become a greater part of investor portfolios, accurate modelling and measuring of performance are critical to solar project investment.
Evan Riley, a PV Specialist at global consultancy Black & Veatch, said:“The measurement of soiling is essential if a project owner or developer wants to truly understand measured or expected performance.”
Available as a standalone unit or integrated with a plant’s existing monitoring system, PVEL’s soiling stations use two full-sized modules, with one allowed to soil naturally while the other is cleaned with an automatic washing system.
Power and energy are monitored for both modules and additional modules can be added to the system and cleaned at varying intervals, allowing staff to determine optimised cleaning schedules for their system. On modules that have coatings designed to repel dirt, the soiling station can be used to compare and evaluate the effectiveness of those coating technologies.