We have had a succession of meters, the old turning dial meter has been known to run backwards, my old digital meter only recorded import, the new digital meter which was fitted with my solar flits from import to export, and my smart meter also records both import and export, but to be paid for export you need a second MPAN number, as in theory you can be paid for export from a different billing agent and who you pay for import.
In the past you could have two different meters one for import and one for export, and could also be paid for export by assuming what was likely, but today only two ways to be paid for export, one is an old meter running backwards, and the other is a smart meter with two MPAN numbers assigned to it.
No, solar plug in doesn't charge batteries so can't export.
Not a clue where that comes from? Plug in solar will likely export, no way to stop it, but to be paid for export, you need a smart meter, and need to complete the G98, with installed solar normally the installer would submit the G98 or G99, and since until August 27th you can't legally use plug in solar, we have no idea of what changes there will be to G98 to allow it to be completed by the householder.
The whole question as to what one will gain with plug in solar, remains open, as to date, all the youtube videos I have watched, the people already had solar, so second MPAN number, or they had batteries.
I can see my use, and work out likely results as my system 7.5 times bigger to plug in. But there are so many other variables, my installed system makes me money in three ways.
1) Input from Solar.
2) Smoothing and transfering energy due to battery.
3) Use of an off-peak supply.
They all work together, and it is nearly impossible to work out gains from just one.
I have three tariffs, off-peak 8.625p/kWh, export 12p/kWh and peak import 32.277p/kWh the latter is higher than the standard rate, so I need to use enough at 8.625p to be worth paying the extra with the 32.277p, so with only 800 watt and no battery, it is unlikely you would even break even using an off-peak tariff.
But it seems the limit is 800 watt per circuit, so 4 ring finals in this house, so 3.2 kWh could be generated, if I get rid of all lighting plugged into my ring finals. Not a clue why it states that, seems daft to me. However unless being paid for export, it would be daft to have multi-units.
It seems the DNO has to issue the MPAN number, not the billing agent.