Unnecessary Grid Usage Despite Available Solar – How to Prioritize Self-Consumption?

[OSS_QV]

PVsyst 8.0: I’m modeling a grid-tied, zero-export PV system (no batteries) and encountering an issue where the grid supplies power even when solar generation is available.For example, in January, Solar should cover all possible load (73.7 + 82.2 ≈ 156 MWh), leaving only 25 MWh to the grid. Instead, the grid supplies 107.5 MWh, and 82.2 MWh of solar is wasted.

I have set grid limitation to 0 kW (no export) and applied at the inverter level.

 

[Bruno Wittmer]

The monthly values do not tell whether PV generation and load are aligned all the time. If you don't have any storage in the system, the load may not be covered in different situations, like outside daylight hours, early in the morning or evening if the load is high, or during cloudy periods in the middle of the day. Therefore, it is quite normal, that you cannot self-consume all the monthly or yearly PV generation, even if it is less than the integrated consumption.