Meteodata and specific production

[SPGT]

With the same tilt angle, module,inverter,location I am getting higher global horizontal radiation but lesser specific production with Meteonorm7.1 and lower global horizontal radiation but higher specific production with NASA data. Why does that happen if every component is same?

[André Mermoud]

For comparing differences bvetween equivalent simulations, you should compare the "Loss diagrams", which will show exactly what is different in the behavior of your systems.

In your case I can see 2-3 possible causes:

- If the ambient temperatures are not the same, the Temperature losses will be different.

- If the Diffuse component is different, the result of the transposition may be different.

- If the Irradiance distributions are very different, the Irradiance losses may be different.