What is the difference between a grid tied and off grid system?
Photovoltaic systems that are connected to the utility grid (utility-connected, grid-tie, or line-tie systems) do not need battery storage in their design because the utility acts as a power reserve. Instead of storing surplus energy that is not used during the day, the homeowner sells the excess energy to a local utility through a specially designed inverter. Off grid systems rely on their own distinct system of solar panels, batteries, and inverters to generate electricity.
