15/10/2025
The Powerful Influence of Peak Sun Hours (P.S.H.)
• A major mistake in the Nigerian solar industry is adopting a "one-size-fits-all" approach. Installing a system size (kWp) proven in Abuja or Zamfara into a humid region like Port Harcourt or Bayelsa virtually guarantees underperformance.
• Two systems with the same components and the same energy demand will have vastly different results due to location differences.
• The primary cause of this failure (barring demand differences) is the variation in Peak Sun Hours (PSH), also known as Equivalent Sun Hours (ESH).
Understanding Peak Sun Hours (PSH):
• Definition: PSH is a foundational metric measuring the amount of usable solar energy available in an area daily.
• What it is: The equivalent number of hours per day when your solar panels receive maximum solar radiation (standardised at 1000 W/m², or AM1.5). It accounts for Low-intensity sun in the morning or evening and cloud cover.
• What it is NOT: It is not the total number of hours the sun is visible in the sky.
• Calculation: Solar Insolation (Wh/m²/Day) is divided by the standard irradiance (1000 W/m²) to obtain PSH
Why PSH Varies Across Nigeria:
PSH creates a clear north-south gradient across the country, primarily due to two factors:
1. Latitude: Locations closer to the equator receive sunlight at a more direct angle, leading to generally higher and more consistent irradiance. More potential for high PSH.
2. Climate:
o Cloud Cover & Rainfall: Dense clouds block direct radiation, causing irradiance to drop significantly. Regions with long rainy seasons (like the South/Coastal areas) have lower PSH.
o Humidity & Atmospheric Moisture: High water v***r scatters and absorbs solar energy, reducing the intensity of light that reaches the ground, leading to consistently lower PSH in coastal regions.
Read the full story; a detailed explanation of the concept of Peak Sun Hours, how/why it varies across locations, the math, and the effect of solar sizing at https://greenterms.ng/why-a-system-that-works-in-zamfara-might-fail-in-bayelsa-understanding-peak-sun-hours/