Heating/hot water from excess solar energy

Technology nows allows us to monitor the electricity which is about to be exported to the grid and divert it to the immersion heater.
It then automatically directs any excess generated electricity, not used by the house, to the immersion heater in the hot water cylinder.

If the load from the house increases, e.g. the washing machine is turned on, the amount of electricity sent to heat water is reduced to help you maintain independence from the grid.