PV Panel performance

The panel performace is assessed by computing the module and inverter efficiencies. They are computed using hte *PVWatts* model, which is implemented in the python *pvlib* library. The efficiency is hereby obtained by dividing the DC power output of a panel by the product of the tilted radiation and the area of the panel. The inverter efficiency is modelled as a function of the DC power output.

The DC power output is computed as a function of the panel performance rating, the cell temperature and the radiation received by the panel. We obtain the panel performance ratings by averaging the values obtained from the datasheet of the mid-range 60-cell mono-crystalline modules from 3 leading manufacturers, namely JA Solar, Jinko Solar and Trinasolar.

The cell temperature is computed from the ambient temperature and the radiation using the *PVSyst* model, also implemented in *pvlib*. The standard values recommended for rooftop-mounted panels are used. We use daily maximum temperature, as this models the worst-case" efficiency for a given month.

The efficiency parameters are computed for the full range of daily maximum temperatures and solar radiation values that are observed in Switzerland. This process is performed in *Efficiency_model.ipynb*. These are then mapped to the temperatures (using pixel sizes of 1km) and radiation values of each rooftop using the script *efficiency_mapping.py*, which may be run on a cluster using the bash script *exec_efficiency_mapping.sh*.

For the description of the metadata of the files, refer to "data/README.md"

Output files

Two output files are generated here:

• *Panel performance*: This file contains the panel and inverter performance characteristics as a function of ambient temperature and tilted radiation received by the panel. It covers the entire range of values found in the data, and does not need to be re-computed if the data is changed (unless a significant increase in tilted radiation results in an extended range of values).

• *Panel performance per roof*: This file contains the performance characteristics (efficiency and performance factor) mapped to each roof for each timestamp. This file needs to be re-computed each time the tilted radiation changes.

Input files

• Tilted radiation: required for both scripts
• Maximum temperature: required for both scripts
• Rooftop characteristics: required to run *efficiency_mapping.py*