Their PV and battery system has an export limited to zero. What does this mean for them if they want to join a VPP?

In this scenario where their local network operator has limited the export of electricity from their home to zero, this means that they won't be able to participate in a VPP. A requirement for their battery to participate in a VPP is to export energy when a VPP event occurs; if this cannot be achieved, they will not be able to participate.