DNO notification for PV

How a proposed solar or storage installation is registered with the correct network operator.

A grid-connected solar PV or battery installation must be recorded with the network company responsible for the electricity connection. In Great Britain, that is normally the DNO. The correct process may be a notification after installation or an application and authorisation before installation.

This is separate from buying electricity. The supplier bills for energy and may offer an export tariff; the DNO operates the local wires, substations and connection. Changing supplier does not change the network operator.

Find the network operator first

The ENA provides a postcode-based network-operator finder. An electricity bill may also identify the operator. Some newer developments are connected through an independent DNO, so it is better to check the actual supply point than to rely on a regional map.

The installer will normally make the submission, but the owner should know which operator received it and keep the reference. Government guidance says the owner is responsible for ensuring that the DNO has received the notification and, for apply-to-connect work, granted authorisation before the work is carried out.

Decide the route from the complete design

For homes and small businesses in England, Scotland and Wales, route selection is governed by G98 and G99. G100 applies separately where the DNO agrees a customer export or import limitation scheme.

G98: connect and notify

G98 applies to a Fully Type Tested installation on the public low-voltage network where aggregate Registered Capacity is no more than 16 A per phase and the other G98 conditions are met. At 230 V, 16 A corresponds to 3.68 kW on single phase or 11.04 kW across three phases.

A qualifying single-premises installation can be commissioned before the DNO is notified. The current G98 Installation Document, system schematic and required cutout photograph must be sent within 28 days of commissioning.

G99: usually apply before installation

G99 applies where generation or storage is above 16A per phase or does not meet current G98. Most small G99 routes require an application and DNO assessment before the equipment is installed or commissioned.

G99 also contains streamlined Small Generation Installation procedures. SGI-1 is notification-only when all of its conditions are met. SGI-2 and SGI-3 are apply-before-install procedures using fully type-tested equipment and, where required, a G100 export limitation scheme.

The inverter’s continuous AC rating is the starting point for inverter-connected generation. The solar array’s DC peak rating and a battery’s energy capacity in kWh do not decide the route. Existing generating equipment must be included, so adding an AC-coupled battery or second inverter can change the result.

G100 is a control standard, not a third connection route

G100 sets the requirements for a customer limitation scheme that controls net export or import at the connection point. It can be part of a G99 design where the DNO agrees less export than the installed generating capacity could otherwise produce.

An export cap does not automatically put a larger installation into G98. The application must show Registered Capacity, the proposed Maximum Export Limit and the G100 scheme as separate items. The DNO decides whether the complete arrangement is acceptable.

Information the installer will need

The exact portal differs between operators, but common inputs include:

the installation address and MPAN
customer and installer contact details
the make, model, capacity and system reference for each new and existing inverter or generator
battery details where storage is included
the commissioning date for a notification, or proposed date for an application
a circuit or single-line diagram
site and location plans for a G99 application
type-test or other compliance evidence
G100 equipment and the requested export limit, where applicable

The MPAN identifies the electricity supply point. It is not the serial number printed on the meter. The bottom line of the supply number on a bill commonly contains the 13-digit core MPAN; the supplier can confirm it if it is unclear.

DNO records

A robust handover file contains:

a copy of the submitted notification or application
the DNO acknowledgement, authorisation, offer or case reference
the final system schematic
the capacities and system references used to select the route
the G98 or G99 commissioning document
any G100 application, product evidence and commissioning record
records of conditions, export limits or later approved changes

A DNO record is not the same as an MCS certificate, an electrical installation certificate, building-regulations evidence or an export contract. Each document has a different purpose. An acknowledgement should not be described as proof of every other approval or eligibility condition.

If an existing installation has no paperwork

Do not recreate a notification from an assumed inverter size or tell the DNO that the system matches a route before checking it. Record the installed make and model, all AC inverter ratings, storage arrangement, MPAN and any existing export-control equipment. Compare the equipment with the current type-test information, then ask the relevant network operator how it wants the installation regularised.

The correct response may depend on when the equipment was connected, whether it was modified, the standard that applied at the time and whether its present configuration matches the available records. The primary sources do not support a nationwide promise that late notification is always accepted without further evidence or action.

Equally, missing paperwork should not be turned into unsupported claims that home insurance is automatically invalid, that a property cannot be sold, or that the installation is automatically ineligible for every export tariff. Establish the facts with the DNO and the relevant insurer, conveyancer or supplier rather than using one missing record as proof of another organisation’s decision.

Northern Ireland uses a separate process

G98 and G99 here are the Great Britain documents. Northern Ireland publishes G98/NI and G99/NI through NIE Networks. G98/NI also covers Fully Type Tested micro-generators up to and including 16A per phase, but its forms, connection requirements and timescales must be taken from NIE Networks rather than copied from a GB DNO.