Technical Guideline 10 of FGW e.V. describes the technical procedure for determining the site yield after commissioning as defined by the EEG 2017. This guideline specifies the procedure for reviewing the site quality based on operating data, which according to the EEG 2017 is to be carried out after five, ten and fifteen years. This procedure is applied to all wind turbines whose value to be applied was determined via the tendering system.

The guideline describes how the site yield and thus the site quality can be calculated on the basis of the stored operating data. An essential content of TR 10 are the technical specifications for the calculation of lost revenues of a wind turbine for the periods in which the turbine was technically not available. These calculations shall be performed if the wind turbine has a time availability below 97%.