A C-46 contractor is assessing a potential site for a ground-mounted PV system. The site has significant mature trees to the south, east, and west, which will cause substantial shading during different parts of the day and year. Removing the trees is not an option. Which of the following strategies would be MOST effective to mitigate the impact of this extensive shading?
- AUtilize a tracking system to follow the sun's path and avoid shade.
- BDesign the array with fewer, but taller, rows to clear the shade.
- CInstall a single large string inverter and oversize the array significantly.
- DDeploy an array of microinverters or power optimizers on each module and optimize array layout.
Show answer & explanationAnswer & explanation
Correct answer: D. Deploy an array of microinverters or power optimizers on each module and optimize array layout.
Given extensive and complex shading where trees cannot be removed, using module-level power electronics (MLPE) like microinverters or power optimizers is crucial. These devices allow each module to operate independently, preventing shaded modules from pulling down the performance of the entire system. Additionally, optimizing the array layout (e.g., splitting into smaller sub-arrays, adjusting row spacing and orientation) to minimize shade impact on individual modules or strings is essential for such challenging sites.
Why the other options are wrong
- A. Tracking systems are designed to follow the sun, but they cannot 'avoid' existing static shade sources like trees; they would still be shaded and lose efficiency, and the added cost of trackers would be poorly utilized.
- B. While increasing row height might reduce some shade, it's often not feasible for mature trees and might not eliminate the problem entirely, especially for complex, multi-directional shading.
- C. A single string inverter is highly vulnerable to shading, and oversizing won't solve the performance degradation caused by partial shading.
PV Shading Mitigation (Complex Sites)
For PV sites with extensive and unavoidable shading, effective mitigation involves using module-level power electronics (MLPE) to optimize individual module performance and carefully designing the array layout to minimize the impact of shade on system output.
- MLPE (microinverters/optimizers) allows individual modules to operate independently.
- Prevents shaded modules from reducing the output of the entire array.
- Strategic array layout (e.g., splitting arrays, adjusting spacing) minimizes shade impact.
- Shade analysis tools are critical for identifying optimal placement and mitigation strategies.
Memory trick: Complex Conundrums? Choose Clever Component Control and Careful Configuration.