We were told to use your electrical goods, dryer etc at night to maximize solar panels. Hubby explained it to me but it went in one ear out the other. So can't help with the why of it. Hehe.
Surely that depends on what amount they are paying per unit vs what you pay to them. On a really good feed in tariff, it makes sense to pump as much electricity in to the grid as possible during daylight hours. But if they are paying you only a fraction of what you pay them (per unit) then it's more cost effective to use as much as possible of your own free energy during the day and as little of theirs?