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Typical Meteorological Year (TMY) vs Typical GHI Year (TGY) vs Typical DNI Year (TDY)
Availability of TMY, TGY and TDY within the Solcast system, and how to extract data for the corresponding values.
Solcast TMYs can be configured by the customer to be TGY, TDY, or anywhere in between.
TMY (Typical Meteorological Year) is a general term for a year of synthetic data that presents realistic "typical" meteorological conditions for a location.
TGY (Typical GHI Year) is a type of TMY that is constructed so that the GHI (global horizontal irradiance) of the TGY matches the long-term average GHI for that location. This is the most common type of TMY used in the Solar Industry.
TDY (Typical DNI Year) is a type of TMY that is constructed so that the DNI (direct normal irradiance) of the TDY matches the long-term average DNI for that location. TDYs are more commonly used for Concentrated Solar Power (CSP) plants which are very sensitive to direct irradiance. Tracking solar systems (dual and single axis) can also benefit from a TDY because they better capture the direct irradiance than a fixed-tilt solar system.
You can select between TGY, TDY, and anywhere in between by adjusting the ghi_weight and dni_weight parameters in Solcast TMY requests.