This paper reports the results of an international interlaboratory comparison study on light‐ and elevated temperature‐induced degradation (LETID) on crystalline silicon photovoltaic (PV) modules. A large global network of PV module manufacturers and PV testing laboratories collaborated to design a protocol for LETID detection and screen a large and diverse set of prototype modules for LETID. Results across labs indicate the reproducibility of LETID testing is likely within ±1% of maximum power (P_MP). In intentionally engineered LETID‐sensitive modules, mean degradation after the prescribed detection stress is roughly 6% P_MP. In other module types the LETID sensitivity is smaller, and in some we observe essentially negligible degradation attributable to LETID. In LETID‐sensitive modules, both open‐circuit voltage (V_OC) and short‐circuit current (I_SC) degrade by a roughly similar magnitude. We observe, as do previous studies, that LETID affects each cell in a module differently. An investigation of the potential mismatch losses caused by nonuniform LETID degradation found that mismatch loss is insignificant compared to the estimated loss of cell I_SC, which drives loss of module I_SC. Overall, this work has helped inform the creation of a forthcoming standard technical specification for LETID testing of PV modules, IEC TS 63342 ED1, and should aid in the interpretation of results from that and other LETID tests.

Photovoltaic modules in desert areas benefit from high irradiation levels but suffer from harsh environmental stress factors, which influence the Levelized Cost of Electricity by decreasing the lifetime and performance and increasing the maintenance costs. Using optimized half-cell module designs mounted in the most efficient orientation according to the plant requirements can lead to reduced production costs, increased energy yield and longer service lives for PV modules in desert areas. In this work, we review the technical advantages of half-cell modules in desert regions and discuss the potential gains in levelized costs of electricity due to reduced material consumption, a higher cell-to-module power ratio, lower module temperatures, better yields, reduced cleaning cycles and finally, reduced fatigue in interconnection due to thermal cycling. We show that half-cell modules are the most cost-effective option for desert areas and are expected to have a relevant lower Levelized Cost of Electricity.

Crystalline silicon solar cells were, are and will continue to dominate the Photovoltaic PV module market. In the past decade, significant efforts have been made to better understand and characterize observations using Electro-Luminescence (EL) to investigate the appearance of c-Si solar cells. While standards have been developed, a clear definition of the nomenclature for observations in EL images is still missing. Within the project PV-Riss, a group comprising manufacturers, advisory experts and research facilities worked on an overview of various observations found in the literature (typically of Al-BSF and PERC cells). The individual observations were categorized into four main categories, namely: 1) single cracks, 2) multi-cracks, 3) anomalies in the electrical circuit and all others into 4) miscellaneous. Each category includes several subcategories to include most relevant observations within EL images. These categories can be applied to all existing and new cell types and are independent on the size (ranging from “old” 4” to new M/G12), shape (full, half, third, x-cut), material (mono, multi), or cell technology (AlBSF, PERC, TOPCON, HJT, IBC, Perovskite on Si), as well as of the PV module design (size, glass/backsheet, glass/glass, internal wiring of the electric circuit). Along with a detailed description of observations in EL images, several important definitions are provided that are essential for general understanding, nomenclature, and the mapping of observations to ensure clear and comprehensive communication and reporting. Following the definition of most relevant observations, key observations will be discussed within a classification proposal. This classification proposal aims to facilitate future discussions and to assess EL observations, combining the risk of power loss that exceeds warranty with the probability of potential electrical safety risk.