Grid connection and solar export in Wales

Solar panels connect to your home first and then to the wider electricity network. Two different parties handle the two jobs. Your local network operator handles the connection, while your chosen supplier pays for the power you export.

This guide explains each role in plain terms. Since Solar Cymru is an independent guide, ask your installer and your supplier for the final word on your case.

Which network operator covers you

Two network operators serve Wales. National Grid Electricity Distribution covers South Wales, from Pembrokeshire to Monmouth and up to Aberaeron and Rhayader. SP Energy Networks, through SP Manweb, covers North Wales.

Public sources do not make the split clear in parts of mid Wales. For that reason, check your own address with the Energy Networks Association operator finder. Climate Action Wales says you must register solar with the local network operator. It adds that the installer usually does this.

The G98 route for small systems

Systems with a combined rating of 16 amps per phase or less follow the G98 route. That means 3.68 kW on a single-phase supply, or about 11 kW across three phases. However, the rating is the inverter’s continuous AC output, not the panel size.

For example, National Grid Electricity Distribution gives a 3 kW single-phase inverter as 13.04 amps, which is G98. A 4 kW inverter is 17.39 amps, which falls under G99.

Under G98 the installer can fit and start up the system first. Within 28 days, they must send the installation document and operation diagram to the network operator. Your installer normally does this. However, several installs within a 500 m area in 28 days use a different route and need agreement first.

The G99 route for larger systems

Larger systems follow G99. In this case the installer applies to the network operator and agrees the connection before commissioning. G99 also covers generation and storage above 16 amps per phase, and batteries count towards the rating.

Sometimes the operator has to strengthen the network before generation can connect, and it can ask the customer to contribute. Because this can add time and cost, ask your installer early. Our post on G98 and G99 in Wales walks through both routes.

The Smart Export Guarantee

The Smart Export Guarantee started on 1 January 2020. It requires licensed suppliers to pay small-scale generators for low-carbon power they export. Suppliers with at least 150,000 domestic customers must offer at least one tariff. Solar up to 5 MW in Great Britain qualifies.

Suppliers set the rate, contract length and terms. Every tariff must pay above zero, and you can pick any supplier that offers one. Ofgem’s 2024-25 report counted 50 tariffs from 11 licensees. The average was about 4.4p per kWh on untied tariffs. Tied tariffs, which bundle a product such as a battery, averaged about 14.5p.

Those are past-year averages, not current rates. Therefore you should compare tariffs before you sign. Our post on the Smart Export Guarantee for Welsh homes explains how to compare them.

Evidence and metering

For solar of 50 kW or less, you must show that the installation and installer hold certification. An MCS certificate works, as does another scheme your supplier accepts. Ask your chosen supplier what proof it needs.

Your exports need a meter. You need an export meter and an export MPAN, and a meter that you can read remotely avoids manual readings. While your installer can advise, the supplier sets the final application rules.

Using power at home or exporting it

Using solar power at home is worth more than exporting it. For example, the Ofgem price cap electricity rate is about 26p per kWh from October to December 2026. In contrast, the 2024-25 untied export average was about 4.4p. This compares two figures from different periods, so treat it as a guide only.

A battery stores spare power for later use. Our post asking whether a solar battery is worth it in Wales works through the numbers. Our page on solar battery storage explains the grid rules. If you plan to charge an electric car, see our post on charging an electric car with solar.

Keep the handover documents

Keep your commissioning and electrical certificates, your MCS certificate and the network operator paperwork. Add the meter details, equipment records and warranties. These documents can support your export setup, and they help a future owner too. The MCS standard also requires the installer to give you handover documents.

Next steps

Ask each installer who owns the network application and when they will send it. Our local pages name the operator for each area. For example, our page on solar installers in Cardiff names one operator. Meanwhile, our page on solar panels around Wrexham names the other.

When you are ready, use our get quotes page to ask MCS-certified installers for a quote. The step is opt-in, so you decide whether to go ahead.