All Plico systems are grid-connected.
Even Plico systems with battery storage will remain connected to the main electrical grid. There will be times when you need to draw from the grid, such as when your battery is empty, or you ramp up high energy use appliances. Your system will also send excess solar energy to the grid (and this is how STCs are allocated to your household) when your battery is full. Grid connection is also essential to earning Plico members financial rewards through our Virtual Power Plant.
An off-grid system costs significantly more because you don't have a buffer to supply additional energy, even momentarily, when it's required. Read this article for a comparison of grid and off-grid systems.