Earth Notes: On GB/UK Solar PV FiTs and Plug-in Solar (2026)

Government to go "further and faster" in becoming energy secure: plug-in solar to become legal.

I asked the FiT administrator for the solar PV system at 16WW how it felt about adding me adding some plug-in solar to my house. we already have solar PV and a battery, and we are metered for export (not "deemed" 50% of generation).

(There was some initial confusion if I was asking about entirely-off-grid gadget chargers!)

I was thinking about putting up south-facing plug-in solar in our back garden in winter to supplement the weak output of our east- and west- facing roof PV. about 1kWp of such optimally placed could generate as much mid-winter (about 1kWh per day) as the 5kWp on the roof, and thus cover about 20% of heat-pump consumption, the heat-pump roughly equalling all other 16WW consumption then.

No export

I would only connect the plug-in solar in winter as we already have more generation in summer than we can use. I would thus not expect any exports to the grid from the plug-in solar. Thus neither the generation nor export meter values reported to the FiT administrator (Ecotricity) for payment should be affected.

However, Ecotricity noted:

...

While I understand your point that the additional plug-in solar may not lead to increased export, under the Feed-in Tariff scheme we have to account for any generation that could potentially be exported to the grid, regardless of intention or typical usage patterns. As your export is based on measured export readings, any additional generation capacity connected behind the export meter may impact the export reading.

As there is limited specific guidance covering plug-in or temporary PV installations within Ofgem's FIT framework, I will need to take this away for further review before confirming a final position.

...

Plug-in batteries

I then asked:

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While you are considering the PV element, may I also ask you to outline Ecotricity's position on ‘plug-in’ battery as can be part of a plug-in solar system or can be bought separately. I believe that these are set up not to export to grid.

Note that I already have an AC-coupled battery system, which may make a difference to your answer.

...

To which the response was:

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[When your new Enphase battery was registered with us] your account should have been moved from measured export to deemed export status. Deemed export is calculated at 50% of the generated units.

This may not have been amended at the time due to battery systems being relatively new. However, Ofgem guidance states that where a battery is capable of charging from the grid, the requirements for export metering are not met. This is because the export meter cannot isolate the amount of electricity exported solely by the FIT installation. Instead, the meter would record total exported electricity, including both export from the FIT installation and export from the storage facility.

...

[With] deemed export, plug-in solar panels and batteries should not affect your FIT payments, as export payments will continue to be based on 50% of your generated electricity. From the information provided, the plug-in solar and battery system does not appear to conflict with FIT requirements, so please feel free to proceed.

It also looks like this is a relatively new product on the market and likely to become more common, so thank you for getting in touch about this.

...

We are all working this out together, it seems!

FiT with deemed export + plug-in = OK

So it seems that from the FiT point of view, if you have deemed (not metered) exports, plug-in solar is probably OK.

You may yet need to talk to your DNO, especially if you might go over the 16A-per-phase limit. Details established over the next few months may clarify.