A Solar Power Diverter
Without a solar power diverter, your hot water cylinder will heat up using purchased grid power before your solar generation has a chance to heat it for free. Then when you are generating surplus power later in the day, you will not need it and you will export it to the grid for a few cents per kWh.
With a solar power diverter, the house hold will not have to purchase electricity from the grid to heat water or other nominated resistive devices. Power Diverters electronically disconnect these loads from the grid and then divert only FREE self-generated surpluses to these loads throughout the day. If needed the diverter will be over ridden with programmable boosts functions or manual override, allowing grid top up only when necessary.