To access the quality of the irradiance estimates provided by our solar dataset, 3TIER examined 120 high-quality reference stations around the globe. Results indicate that 3TIER's standard error is 5% for GHI and DIF and 9% for DNI. These results are consistent across the globe, which means 3TIER data can be used worldwide with the same degree of certainty.

Compared to publicly available data sources, such as NREL and NASA, 3TIER's dataset has similar bias and standard errors, but significantly lower root mean square errors (RMSE). A lower RMSE indicates that our estimates of irradiance are closer to actual observed values on an hour-by-hour basis.

For additional information, please see 3TIER's global solar validation white paper:

• Global Solar Validation White Paper