Global solar data
GHI • DNI • DHI • GTI • PVOUT
Use the right resource variable for the right engineering question. Large, clearly labelled values make the resource terms easy to read before you open a data source or simulation tool.
GHIGlobal Horizontal IrradianceUseful for broad solar-resource comparison and many PV yield workflows.
DNIDirect Normal IrradianceImportant for beam radiation and technologies that track the sun.
DHIDiffuse Horizontal IrradianceRepresents diffuse sky radiation received on a horizontal plane.
GTIGlobal Tilted IrradianceRadiation on a selected tilted plane, closer to the geometry of a fixed PV array.
PVOUTPV electricity output estimateModelled output depends on configuration, resource, losses and modelling assumptions.
How a PV designer should use resource data
Start by defining the design location and the purpose of the analysis. A preliminary feasibility study may only need a long-term resource estimate. A detailed simulation needs a consistent meteo dataset and clearly documented assumptions.
Document these items
- Latitude, longitude and site elevation where relevant.
- Resource provider and dataset name.
- Time period / typical meteorological year basis.
- GHI, DNI, DHI or other variables actually used.
- Transposition model and plane-of-array assumptions.
- Temperature source and design temperature basis.
- Shading, soiling, availability, mismatch and other losses.
External site and climate resources
ASHRAE — Global Climate / Weather Data
Nearmap — High-Resolution Aerial Imagery
EagleView — Aerial Imagery & Property Data
Google Earth — 3D Site and Terrain View