Is Your PV System Underperforming? A Guide to Optimizer Application and Configuration

In practical applications of photovoltaic (PV) power generation, issues such as shading, differences in module orientation, and module degradation often lead to a decrease in system output. Research indicates that shading can result in power generation losses of up to 70% (Source ①: NREL). Particularly when a specific module is shaded, the current and power output of the entire series circuit can significantly decrease. This is where photovoltaic optimizers come into play. They adjust the output current of the affected modules through internal DC-DC control circuits, achieving current matching with other modules and effectively reducing generation losses due to mismatch. This article will detail the specific application needs for photovoltaic optimizers in both existing and new installations, as well as the solutions they provide.

Key Measures for Enhancing Output in Existing PV Plants

For operational photovoltaic plants, retrofitting with optimizers is undoubtedly a crucial upgrade strategy. This technology not only significantly boosts system output but also provides strong support for the long-term stable operation of the plant. Here are some typical application scenarios:

Retrofitting Old Plants (Without Replacing Modules) Some older plants that have been operational for many years often experience a decline in output due to module aging, performance degradation, and changes in working environment. According to research, the power generation efficiency of aging modules may decrease by as much as 20% (Source ②: IEA), leading to severe mismatch issues. Installing optimizers can not only address this problem but also recover lost generation to the maximum extent. Additionally, the module-level monitoring feature allows real-time tracking of module performance, enabling precise identification of problematic modules and saving maintenance time.

Retrofitting Old Plants (Complete Module Replacement) Typically, plants constructed before 2018 plan to replace old modules with the latest ones. During this replacement, changes in module dimensions may cause shading (as illustrated below), resulting in power loss. Based on Sheng Gao's project experience, systems utilizing optimizer technology can significantly enhance overall generation in the presence of shading, with average increases of 15% or more.

Larger new modules may cause some shading

Retrofitting Old Plants (Partial Module Replacement) With the rapid development of module manufacturing, when modules in older plants need to be replaced due to damage, they often face the dilemma of the original manufacturer no longer producing the same specifications. Simply replacing damaged modules with popular current market modules may lead to mismatch issues within the same module string. To address this challenge, retrofitting with optimizers emerges as a more economical and effective choice, effectively eliminating mismatch phenomena and ensuring plant efficiency.

Shading Mitigation Photovoltaic plants typically have a lifespan of up to 25 years, during which surrounding environments may change. Newly constructed buildings, transplanted trees, or additional rooftop equipment can introduce shading issues for photovoltaic modules. In such cases, the application of optimizers is particularly important. By employing optimizer technology, the impact of shading on system output can be significantly reduced, recovering losses caused by shading.

Optimization Configuration Recommendations for New Installations

For users who have not yet installed photovoltaic systems, proactively configuring optimizers is equally significant. From the initial planning and design phase of the plant, optimizers should be considered to ensure high efficiency, stability, and intelligent power generation capabilities from the outset. The following scenarios are particularly suitable for the installation of photovoltaic optimizers:

Complex Roof Structures One of the core factors determining the scale of rooftop photovoltaic installation is the orientation of the roof. Modules in the same string oriented in two different directions can lead to power losses. Photovoltaic optimizers enable each module to operate at its maximum power point, unaffected by other modules in the same string, thus maximizing the utilization of rooftop space.

Shading Issues Shading from surrounding rooftops can cause power generation losses in photovoltaic systems. Even minor tree shade or overhead line shadows can significantly impact the overall output of the plant. Photovoltaic optimizers utilize module-level MPPT (Maximum Power Point Tracking) to independently optimize shaded modules, thereby enhancing overall system generation.

Variable Natural Environments Common environmental factors such as dust accumulation, bird droppings, and snow can also greatly affect the output of photovoltaic plants. If your rooftop is located in an area with variable natural conditions, it may lead to underperformance in PV generation. Installing optimizers can effectively address these challenges, ensuring stable power generation.

Safety and Maintenance Requirements Photovoltaic systems continuously generate voltage, and systems that cannot perform low-voltage safety disconnections in the event of faults or fires pose safety risks. Photovoltaic optimizers can promptly identify potential risks through module-level monitoring and complete rapid shutdown within 15 seconds, reducing voltage to safe levels and ensuring the safety of both the photovoltaic system and maintenance personnel.

In summary, photovoltaic optimizers play a vital role in enhancing the output of photovoltaic systems, ensuring safety, and facilitating maintenance. Whether for operational or new photovoltaic plants, retrofitting with optimizers in specific scenarios is a wise choice.

Sources:

① NREL PV Performance: https://www.nrel.gov/docs/fy19osti/72399.pdf 

② IEA Photovoltaic Power Systems Programme: https://iea-pvps.org/