The lowest ican buy in 15.44 p per unit and export at 27.44p max.
This is where one needs to do the sums appropriately for one's situation and consumption profile. I can buy in at £0.08 overnight but I don't get anything for export so it doesn't make sense for me to have a battery that is too large. I charge 7KWh overnight and then use it in the day when I would be paying £0.30 for the power, so I save around £45/month. In the summer I give loads of power back to my supplier and earn nothing for it, but I'm happy to support Ecotricity, I like the company ethics and a fair few of my mates work for them.
The only thing I would change about my installation is that when I had mine installed the technology to isolate the panels from the grid in case of an outage was pretty expensive, now it's very feasible, so if I were to do it again I'd go for a Tesla Powerwall with 10KWh that would give me grid independence for 24 hours. Mind you, in the nearly 40 years we've lived here we've never had a power cut longer than a few hours so it's a pretty low risk I reckon.
