Can You Use Solar Panels with a Prepayment Smart Meter?

Yes — plug-in solar works with prepayment meters, and you'll see your credit last longer. Here's what's different and how to get the most from it.

Prepayment Meters and Solar: The Basics

Roughly 4.5 million UK households are on prepayment meters. If you're one of them, you can absolutely use plug-in solar — and in some ways, the savings feel more immediate than on a credit meter.

With a SMETS2 prepayment meter, your credit balance decreases as you consume electricity. When your plug-in solar panels are generating, your consumption drops, and your credit lasts longer. You can literally watch the deduction rate slow down during sunny hours on your in-home display.

How Solar Interacts with Prepayment

During generation: your solar panels offset your household demand. If your panels produce 500W and your home is using 600W, you're only drawing 100W from the grid. Your credit depletes at a fifth of the normal rate.

During export: if your panels produce more than you consume, the surplus goes to the grid. On a prepayment meter, this does not add credit to your balance automatically. Export payments are handled separately through the SEG, which pays into a separate account or bank transfer — not onto your prepayment card.

At night: normal prepayment behaviour resumes. Your solar isn't generating, so credit depletes at the usual rate.

Can You Get SEG on Prepayment?

Yes, but it's slightly more involved. You need:

A SMETS2 prepayment meter with the export register enabled
An SEG agreement with a participating supplier

The SEG payments typically go to a bank account rather than your prepayment meter credit. Some suppliers are developing systems to credit prepayment accounts directly, but this isn't universal yet.

Even without SEG, the import savings alone make plug-in solar worthwhile on prepayment. Every kWh your panels produce that you use directly is a kWh you didn't need to prepay for.

Switching from Prepayment to Credit

If you're on a prepayment meter involuntarily (e.g., installed by a previous tenant or as a condition of debt), you may be able to switch to a credit meter. Since January 2025, Ofgem has strengthened rules around involuntary prepayment. Contact your supplier to discuss options.

Switching to credit with a SMETS2 meter opens up time-of-use tariffs and simpler SEG arrangements, which improve the overall return from solar.

SMETS2 Prepayment vs SMETS1 Prepayment

Older SMETS1 prepayment meters have the same limitations as SMETS1 credit meters for solar: no export register, potential issues with reverse current, and loss of functionality when switching suppliers.

If you're on a SMETS1 prepayment meter, request a free upgrade to SMETS2. The smart prepayment functionality (top up via app, no key needed) transfers to the new meter.

Practical Tips for Prepayment Solar Users

Top up strategically — in summer when your solar is generating well, you'll use less grid electricity. You can top up less frequently or in smaller amounts.

Monitor the IHD — your in-home display shows real-time consumption rate. On sunny days, watch it drop when your panels are generating. This is the most satisfying part of prepayment solar.

Track savings manually — compare monthly top-up amounts before and after solar installation. The difference is your saving.

Consider a battery — for prepayment users, a battery is particularly valuable because it shifts solar generation to evening hours, directly reducing the credit you use.