The Real Impact of Solar Module Size on PV Plant Design:

Impact of solar module size on PV plant design

Introduction

Over the past few years, PV module sizes have increased significantly, moving from 60-cell and 72-cell modules to large-format modules exceeding 500 W, 600 W, and even 700 W. While higher wattage modules reduce the number of panels required, the real impact of module size goes far beyond module count. It affects structural design, electrical design, logistics, installation, and overall project economics.

1. Impact on Structural Design

Larger modules mean increased module area, weight, and wind load. This directly affects mounting structure design.

  • Higher wind pressure on larger surfaces
  • Increased bending moments on rails and supports
  • Requirement of stronger purlins, rafters, and foundations
  • Increased structure cost in high wind zones

In some cases, the structure cost increase can offset the savings from fewer modules.

2. Impact on Land Utilization and Layout

Large modules can improve land utilization in utility-scale solar plants because fewer mounting tables and foundations are required. However, in irregular plots or rooftop projects, large modules may cause:

  • Space mismatch
  • Edge losses
  • Difficult layout optimization

Therefore, module size should be aligned with site geometry.

3. Impact on Electrical Design

Bigger modules generally mean:

  • Fewer modules per string (due to higher Voc)
  • Reduced number of strings
  • Reduced DC combiner boxes
  • Lower DC cable quantity

However, higher current modules may require larger DC cable sizing, which can increase cable cost.

4. Impact on Logistics and Installation

Large modules are more difficult to handle:

  • Transportation limitations
  • Higher risk of module damage
  • More manpower required for installation
  • Slower installation in rooftop projects

But in large ground-mounted plants, fewer modules can reduce installation time overall.

Conclusion

The selection of PV module size should not be based only on module wattage. The optimal module selection depends on structural design, land layout, electrical configuration, logistics, and project cost optimization.

In modern PV plant design, the best project is not the one with the highest wattage module, but the one with the most optimized overall system design.

GreenEnco® design optimisation service offers a unique opportunity to ensuring that your project is adequately designed. Our Technical Due Diligence services will ensure that the relevant international standards and best practices are being adhered to throughout your project. Contact us on how we can add value to your project and minimise any future asset downtime.