This is an interesting household using a combination of: E10 / Solar PV / Sunamp heat battery.
Much of the time, solar PV doesn’t generate when the household needs it, so it’s exported to the grid with no payment to the householder. However in this house the Sunamp heat battery is charged by the solar PV – capturing the wasted energy for use as hot water later. It can be topped up at off-peak times using the E10 meter. Very clever!
Here’s a brief video explaining how it fits together:
Andy’s amazing live energy monitor from this house: http://wattson.energyhive.com/dashboard/AndyT
Robert Llewellyn @ Fully Charged: https://www.patreon.com/bobbyllew