Your panels are on the roof and the app shows power flowing. To actually get paid for the electricity you export, three pieces of paperwork need to line up: your MCS certificate, your DNO confirmation, and a Smart Export Guarantee application. None of it is hard, but plenty of households leave money on the table by never finishing the job.
The paper trail, in order
It runs like this. Your installer commissions the system and registers it on the MCS database, which produces your MCS certificate, usually within ten working days of installation. They also notify the DNO (or will already hold a G99 approval for bigger systems). With those two documents plus a smart meter, you apply to an energy supplier for a Smart Export Guarantee tariff. Once accepted, every unit you export earns money automatically.
Two of those three steps are your installer's job. The SEG application is yours, and it's the step most often forgotten.
The MCS certificate
The MCS certificate is the master document. It proves your system was installed by a certified company to the required standard, and it carries a unique certificate number that suppliers check before paying you a penny of export income. No MCS certificate, no SEG. It also matters for your home insurance, for warranties, and for the buyer's solicitor if you ever sell the house.
Your installer must register the installation and send you the certificate; chase them if nothing has arrived within two weeks. You can verify any certificate yourself on the MCS database at mcscertified.com, which is also a useful trick before hiring an installer in the first place.
The DNO confirmation
As covered in our DNO guide, every system is either notified to the local network operator after installation (G98, small systems) or approved by them beforehand (G99, larger ones). Either way a confirmation document exists, and some SEG suppliers ask to see it during sign-up alongside the MCS certificate.
Ask your installer for a copy as part of your handover pack. A decent handover pack should contain the MCS certificate, the DNO notification or approval, an electrical installation certificate, warranty documents for panels, inverter and battery, and a user guide for the monitoring app.
The smart meter and the SEG application
SEG payments are calculated from half-hourly export readings, so you need a working smart meter (SMETS2, or a SMETS1 meter that has been migrated). If you don't have one, your supplier will fit one for free, though waiting times vary. Book it early, ideally before the panels go in, because you cannot be paid for exports the meter never measured.
Then pick your SEG supplier. You do not have to use the company that supplies your electricity, and rates vary enormously, from a token 4p per kWh to around 15p on the best flat tariffs in 2026. Battery owners can do even better on time-of-use export tariffs that pay a premium in the evening peak. Switching SEG supplier later is allowed, so start with the best rate you qualify for today.
If the money doesn't arrive
Most SEG applications are approved within a couple of weeks and payments appear quarterly or monthly depending on the supplier. If nothing happens, the usual culprits are an unregistered MCS certificate, a smart meter that isn't sending half-hourly readings, or an application that quietly stalled waiting for a document.
Check your supplier's portal for the application status, confirm your meter is in half-hourly mode, and re-send the MCS certificate if asked. If a supplier is genuinely unresponsive, the Energy Ombudsman covers SEG disputes once you've given the supplier eight weeks to resolve a complaint.