Glossary

Solar Irradiance

The power of solar radiation received per unit area, measured in watts per square meter (W/m²).

What is Solar Irradiance?

Solar irradiance is the measure of solar power received on a surface per unit area, expressed in watts per square meter (W/m²). It is a fundamental metric in solar energy system design and performance prediction.

Types of Solar Irradiance

Global Horizontal Irradiance (GHI)

The total solar radiation received on a horizontal surface, including both direct and diffuse components.

Direct Normal Irradiance (DNI)

The solar radiation received directly from the sun on a surface perpendicular to the sun’s rays.

Diffuse Horizontal Irradiance (DHI)

Solar radiation scattered by the atmosphere that reaches a horizontal surface from all directions except directly from the sun.

Why It Matters for Solar Design

Solar irradiance data is essential for accurately predicting how much energy a solar system will produce. Tools like SurgePV use TMY (Typical Meteorological Year) data to model irradiance at any location worldwide.