A grid connected renewable energy system converts DC electricity from a power source, such as solar panels, to AC mains power and feeds it into the grid. It usually consists of the energy source, an inverter and a meter.
If there is a mains grid power failure, a grid connected renewable energy system disconnects from the grid and energy from solar panels is not available.
Battery banks connected to the grid, with an appropriate inverter, may work as an uninterruptable power supply to make energy available during a power outage for all or some of the electrical loads in a home or business.
Although costs are currently very high and extra components are required, it is technically possible for such a system to enable one of these options:
energy from the grid to be stored during off-peak times of lower price and supplied during peak times where energy is charged at a higher rate (at homes with a time-of-use tariff for energy)
surplus energy from renewable energy generators to be stored for use on site (at homes without a premium feed-in tariff for exported energy).
One diagram shows a house that has solar panels that are connected to a grid connect inverter, via a switch board and electricity meter to the power grid.
Grid connected system.