Yichi Zhang, General Manager of PV Module, Solar – TUV Rheinland | Topic: Energy Yield: Looking beyond the Standard Test Conditions
The energy delivery of a PV module is of primarily importance for the economical operation of a PV power plant. Commonly, PV modules are sold based on nominal power value, which is related to standard test conditions (STC), while real world operating conditions differ significantly from STC. However, this parameter does not take into account the specific properties of different PV module technologies and their suitability for operation in a certain climate.
Our research has revealed astonishing differences in the specific energy yield performance of PV modules of up to 25% depending on operating climate of the test site. Thus, to optimize the energy yield delivery and to reduce the LCOE of a PV system it makes sense to look beyond STC performance and to select PV modules suited best for a certain location.
While uncertainties of energy yield prediction by computer simulation tools are high, the series of standards IEC 61853 shows indoor measuring methods to rate and compare the energy delivery of different PV module technologies for varying operating conditions. Since more and more bifacial PV module technologies arise, recently an optimal energy yield delivery became topic of great interest for crystalline solar industry and the market seeks feasible solutions to compare and rate different products regarding their energy production.
This presentation shows results of PV modules performance characterization in the laboratory as well as outdoor energy yield measurements of conventional monofacial, bifacial and thin-film PV module technologies. As indicator for the suitability and energy yield delivery of a PV module type for a certain climate TUV Rheinland developed the first “Energy Yield Rating Label” for PV modules, which is independent of annual meteorological fluctuations and useful to compare all available PV module technologies. This label will give guidance to planers and investors of PV power plants to identify the