Created by R.G., ZHAW, on 15.07.2024
In order to qualify for federal support in accordance with Article 71a, the planned installation must comply with the requirements set out in this Act. This necessitates the submission of a yield simulation of the system. The specific requirements for this are outlined in the Swiss federeal office of environment’s (SFOE’s) guidelines. This article provides an overview of the application process and the parameters that must be taken into account.
Application procedure
The process in the image below shows how the application procedure takes place. The steps colored in blue are worksteps carried out by the applicant and the red ones by the SFOE. It is recommended that the simulations should already ensure that sufficient yield can be achieved so that the minimum requirements of the federal government are not reached. Otherwise, the system already built may not receive any support from the federal government, as it could be that in the three measurement years, poorer years in terms of irradiation could mean that the specifications cannot be met on average. In order for the project to be submitted, the following documents must be known (individually or in the simulation reports):
- Map with marked floor plan of the PV system
- Schematic diagram of the PV system
- Datasheets for PV modules, inverter and transformer
- Technical drawing/sketch of the substructure, including the distances, inclinations, PV modules, shading angles and the inclination of the terrain.
- Far horizon data used as a diagram
- Meteorological data used in monthly resolution for reference period
- Bifaciality parameters used
- Monthly albedo values used
- Simulation reports
Methodology for yield simulations
The applicant is at liberty to select the simulation tool and the source of the environmental parameters, including factors such as the horizon, albedo and meteorological data. In order to submit an enquiry, it is necessary to prepare a detailed simulation report in which the data used is listed and explained. The illustration below provides an overview of the model parameters that should be included in the yield simulations. Values have been divided into the following categories: environmental parameters (green), electrical system parameters (brown), mechanical system parameters (blue), losses (grey) and bifaciality parameters (violet). Bifacial and loss parameter values, written in white, represent the values that the SFOE will use to double-check the applicants› yield simulations. It is permitted to use different values if they are known or if they are well-founded in the reports.
If there are any uncertainties on the part of the SFOE, they will request additional documents and check the yield forecast with a recalculation. To check it they will use the PVsyst tool with inputs of Meteonorm. Should the recalculation result in discrepancies with those of the applicant, the latter is afforded the opportunity to justify the differences or to adjust its values.
Links to Sources
- Original Document (German): www.pubdb.bfe.admin.ch → «Wegleitung zur Ertragsberechnung für PV-Grossanlagen»
- Swiss Federal Office of Energy: Large-scale photovoltaic systems
