Long-term Averages from Time Series or TMY vs. Prospect

Unlike Solargis Evaluate Time Series or TMY data, which are retrieved in real-time when an order is made, Solargis Prospect relies on a pre-calculated database that is updated every year.

The impact of this on long-term averages is influenced by the following factors:

• Irradiance Model. Evaluate uses the latest model available at the time of order, while Prospect uses the model available at the last database update.

• Period of Years. Evaluate uses the most recent data available at the time of order, whereas Prospect uses the period of data available at the last database update.

• Terrain model. There are small differences in spatial resolution between Evaluate and Prospect.

Periods and model versions that are used on the pre-calculated Prospect database can be always checked in the Prospect app for any chosen site under the section metadata, available on the detailed view of the project. On the other hand, on Evaluate, metadata is always included on the first rows of the CSV files delivered with the service.

The newest releases, including database updates and model improvements, are announced in the Release Notes section.

In general, the difference in annual averages of Global Horizontal Irradiance (GHI) calculated from time series or TMY under Solargis Evaluate and data available in Solargis Prospect can be up to ±1%.

To account for this uncertainty, it is recommended to add ±1% to the model's uncertainty factor. For example, if the model uncertainty for GHI annual values provided with Evaluate’s service is ±4%, it should be increased to ±5% when using Prospect values for the same site. Please note that site-specific uncertainty values are only provided via Evaluate.