The network operator application, explained

Connecting a generator to the grid requires telling the network operator. For most domestic solar systems this is a notification after the work is done; for larger ones it is an application for permission beforehand.

Your installer handles it. It is worth understanding anyway, because the route is set by a specific number on your quote, it can add weeks to your timeline, and the answer can cap what you are allowed to export, which changes the savings figure you were quoted.

Who the network operator is

Not your electricity supplier. The distribution network operator owns and runs the cables and substations in your area, and there is exactly one for your region regardless of who you buy electricity from. The industry body Energy Networks Association publishes the connection rules and can point you at which operator covers your postcode.

Switching supplier does not change your network operator.

The two routes, with the actual numbers

G98, notification after connection, applies to installations up to 16 amps per phase, which is 3.68 kilowatts of inverter capacity on a single phase supply. The installer connects the system, then notifies the operator within 28 days, providing the technical details. No waiting, no permission required, and the operator cannot refuse a compliant notification.

G99, application before connection, applies above that threshold. The operator assesses whether the local network can accept the generation, and may approve it, approve it with conditions, or require reinforcement work. The assessment typically takes weeks, occasionally longer in loaded areas, and the installation cannot lawfully proceed ahead of it.

Note what the threshold measures: the inverter’s rating, not the panels’. This is why so many UK systems pair a larger array with a 3.68kW inverter, keeping G98 simplicity at the price of some clipping on the brightest days, and why “which inverter, which route” is really one question.

Ask which applies to you

Two questions for your installer, before you sign:

“Does my system require G98 notification or a G99 application, and if G99, is the approval in hand?”

“Do you expect an export limit to be applied?”

The first protects your timeline: a quote promising installation next week for a system that needs prior G99 approval has skipped a step. The second is the one that matters financially.

Export limits, and what they do to your sums

Where the local network is constrained, an operator may permit the installation on condition that export is limited to a certain level, enforced by the inverter.

The system still generates fully. You simply cannot send more than the limit to the grid, so surplus above it is curtailed and lost.

Scale decides the damage. A household consuming most of its generation barely notices: its export rarely reaches the cap. A large array on a low daytime consumption house is the opposite case, because its midday surplus is exactly what the cap cuts, and every curtailed unit was worth the 12p or so an export tariff pays. A battery softens the blow by absorbing the curtailed peak for evening use, which is worth pricing when a limit is on the table.

If a limit is expected, ask for the savings projection to be redone with it applied. A projection modelling unrestricted export on a system that will be capped is overstating the return, and the overstatement lands entirely on the export line.

Where it gets slower

Delays are usually a function of the area rather than the property. Some networks are heavily loaded, particularly where there has already been a lot of generation connected locally, and assessments take longer.

If you are on a timeline, ask early what the current turnaround is in your area. This is the step most likely to hold up the installation sequence, and it is the one nobody’s scaffolding schedule can hurry.

Batteries count too

A battery that can export to the grid is treated as generation for these purposes, so adding storage to an existing solar system usually requires its own notification or application, and can tip a previously-G98 property over the threshold if the battery inverter adds capacity.

This catches people retrofitting. If your original system was notified without a battery, adding one is a change the operator needs to know about. Your installer should handle it; confirm they have, in writing, because the paperwork trail matters later.

What you should end up with

Keep whatever documentation comes back. You will want it if you later add storage, extend the array, or sell the house, and it is the record of what is permitted at your property.

If an export limit was applied, make sure you know the figure and that the inverter is actually configured to it. A limit agreed on paper and not implemented is a compliance problem sitting in your loft, and one a future export tariff registration can surface at the least convenient time.

Do not do it yourself

This is one of the reasons a certified installer is worth having. The notification requires technical details of the equipment and the installation, and getting it wrong, or skipping it, causes problems when you later apply for an export tariff: suppliers registering you for the Smart Export Guarantee rely on the installation being certified and properly connected, and a system the network does not know about is a system no supplier will pay. The paperwork is dull precisely because it is load-bearing.