How much solar can I export to the grid in the UK?

Quick answer

There is no single rule saying every UK home can export only 3.68kW of solar. In Great Britain, 3.68kW on a single-phase supply is the familiar 16A-per-phase threshold used by G98. It is a connection-rule threshold, not a universal ceiling on every solar installation.

If the proposed generation is above the G98 threshold, the installation normally moves into G99 and the Distribution Network Operator assesses the connection. The DNO may approve the proposed capacity, agree a lower export capacity or require an export-limitation arrangement.

Is 3.68kW the maximum solar export limit?

No. Under the Great Britain G98 route, compliant generation at a single premises can have a combined registered capacity up to 16A per phase. At 230V, that is 3.68kW on a single-phase supply or 11.04kW across three phases.

Going above that threshold does not mean the system cannot be connected. It means G98 is no longer the normal connection route. G99 applies to generation rated above 16A per phase, or where the installation otherwise falls outside the current G98 requirements.

Read the full G98 vs G99 solar guide

What happens if your system is above 3.68kW?

A G99 application lets the DNO assess the proposed generation before connection. The outcome depends on the equipment, phase arrangement and the capacity of the local network rather than one national household number.

The DNO can approve the proposal as submitted, agree a particular Maximum Export Capacity or require other connection conditions. That is why two similar solar systems in different locations can receive different connection outcomes.

What is a G100 export limit?

G100 is the engineering framework used for export limitation. An export-limitation scheme measures the power flowing out through the grid connection and controls generation, storage or demand so the agreed export capacity is not exceeded.

This can allow a property to have more solar or battery capacity installed behind the meter than it is permitted to export at one moment. The export setting is part of the agreed connection and should not be treated as a customer-adjustable setting.

Does an export limit mean wasting solar?

Not necessarily. An export limit controls what crosses the grid connection, not simply the headline size of the solar array. Electricity being used in the home does not need to be exported, so a larger system can still serve household demand while net export stays within the agreed limit.

Curtailment can occur when solar generation is high, household demand is low and there is nowhere else for the surplus electricity to go. A battery or flexible daytime load can change that pattern, but the value depends on the system design and household use.

Can a 4kWp or 5kWp solar array export more than 3.68kW?

Panel capacity in kWp and inverter AC capacity are different numbers. A 4kWp panel array paired with an inverter whose registered output is limited to 3.68kW cannot produce more than that inverter limit on the AC side, even though the panels have a higher DC peak rating.

A system using a higher-capacity inverter may be able to export more than 3.68kW if the correct G99 connection has been approved. Alternatively, the installation may have a higher generation capacity but use G100 export limitation to stay within the DNO-agreed export capacity.

kW and kWh answer different export questions

An export limit such as 3.68kW is a power figure: it describes how much electricity can flow at one moment. Annual exported electricity is measured in kWh and depends on annual solar generation, household self-consumption, battery behaviour and any periods when export is curtailed.

The 3.68kW G98 threshold therefore does not create a universal annual kWh export allowance. SEG payments are based on eligible metered exported electricity, using the tariff rate and terms offered by the chosen export supplier.

Compare current SEG rates and export tariffs

What changes if you add a battery?

Battery storage can change the grid-connection assessment because storage can also export through an inverter. Your installer should consider the combined generation and storage arrangement rather than looking at the solar panels in isolation.

Current National Grid guidance also describes a G99 fast-track route for certain single-phase combinations of G98-compliant generation and storage where a G100-compliant scheme restricts export to 16A per phase or less. The exact route still needs to be confirmed for your installation and network area.

What about Northern Ireland?

Northern Ireland uses its own G98/NI and G99/NI standards through NIE Networks. NIE describes G98/NI as applying to fully type-tested micro-generators up to and including 16A per phase, with G99/NI covering the wider generation-connection requirements.

The practical lesson is the same: do not assume one headline kW figure tells you the full connection answer. Ask the installer which NIE Networks route applies and what export capacity is being requested or agreed. SEG itself applies in Great Britain, not Northern Ireland.

What to ask your solar installer

The quote should make the grid-facing design understandable before you sign. If the installer simply says the system is 'limited to 3.68kW', ask whether they mean inverter registered capacity, DNO-agreed export capacity or a G100 export setting.

• What is the panel array capacity in kWp?
• What is the inverter registered AC capacity in kW?
• Is the connection being handled under G98, G99 or a fast-track route?
• What Maximum Export Capacity is being requested or has been agreed?
• Is a G100 export limitation scheme being installed?
• If there is a battery, how does it affect the connection application?
• Will the DNO approval and export-limit details be included in the handover pack?

Put the export limit into your solar decision