At the risk of being off topic as far as your programmable charging options go, which are great ideas, a cautionary tale of helping "conserve" for the government.
Years ago now here in GA we had a bad drought and they showed pictures of low lake levels and boats on dry land and such. So the mayor of Atlanta at the time made water her top concern.
They asked everyone to cut their water use back by about 10% to help out, and we did, in fact we cut water usage by 22%.
Not long after that the water company said their budget was short by (you guessed it ) 22% so they would need to raise rates by oooo we don't know 22%?
Later on the rain cycled back and the lakes filled back up and the grass was green again but the water company felt it was better just to keep that extra 22% (just in case)