Absorption

In photovoltaics, shading refers to the reduction of solar irradiance on solar panels due to external influences. These influences can be either static (e.g., trees, buildings, antennas) or dynamic (e.g., clouds, shadows from passing vehicles).

Effects:

  • Power reduction: Shading significantly reduces the power output of affected modules, as less sunlight is converted into electrical energy.
  • Hotspots: If individual solar cells within a module are shaded, hotspots may form. These can overheat and reduce the module's lifespan.
  • Voltage drop: Shaded modules can cause a voltage drop in the entire string, impairing the overall system's performance.

Causes:

  • Structural conditions: Trees, buildings, terrain elevations in the surroundings, and even the building's own roof structure can cast shadows.
  • Natural influences: Clouds, fog, as well as the sun's movement throughout the day and year, create constantly changing shading patterns.
  • Foreign objects: Bird droppings, leaves, snow, or other foreign objects on the modules can also cause shading.

Countermeasures:

  • Optimal orientation: Careful orientation of the modules towards the south and at an angle toward the celestial equator minimizes shading from natural influences.
  • Module selection: Solar modules with bypass diodes can mitigate the effects of shading by redirecting current around the affected cells.
  • Power optimizers: These devices allow individual power optimization for each module, reducing the impact of shading.
  • String design: Smart string design, grouping modules with similar shading together, can improve overall system performance.
  • Cleaning: Regular cleaning of the modules removes debris and increases the system's efficiency.

Conclusion:

Shading is one of the most important factors affecting the performance of a solar power system. Careful planning and the selection of appropriate components can minimize the negative effects of shading and ensure the system's long-term yield.

Additional keywords: Hotspots, Bypass diodes, Power optimizers, String, MPP tracker