Best answer by Llamedospete
I don't think that you can at the moment as I believe that this is a trial by OVO, and also only in one or two areas off the country.
I have domestic batteries fitted together with economy 7 tariff and can really recommend them, I have a 7.2kwh Sofar Solar and Pylontech system that I bought direct from an online supplier.
I also have 4kwp of solar PV on the roof, the two compliment each other.
So far I am really pleased with the results and they are performing very well.
If you want any further info I will be pleased to supply it.
RRegards to all Pete.