Helpful video reference. NXTGEN Energy Limited, an MCS-certified solar installer based in Essex and operating across Kent and London, explains the DNO application process in their video "Understanding DNO Applications for Solar Panels with NXTGEN Energy - Your MCS Certified PV Installer". Worth watching to understand what your installer is doing on your behalf and why the paperwork matters.
1. Confirm which form applies to your system
The threshold that separates G98 from G99 is the export capacity of your system, measured in kW per phase.
- G98 (notify after installation): systems up to 3.68 kW per phase (equivalent to 16 A per phase) on a single-phase supply. Most domestic rooftop solar installations fall into this category. The installer commissions the system, then submits the notification within 28 days.
- G99 (apply before installation): systems above 3.68 kW per phase, or any system the DNO classifies as requiring prior approval. G99 requires the installer to submit an application and receive DNO approval before the system is energised. This applies to most larger solar arrays, all three-phase systems, and most battery storage systems above a certain size.
Your installer will know which route applies. If the system has a 4 kW or larger inverter, or if battery storage is included, ask them explicitly whether they are following the G98 or G99 route and when they expect to submit.
2. Find your DNO and its online portal
The UK has six major Distribution Network Operators. East Kent, including Sandwich, is served by UK Power Networks (UKPN). If your property is elsewhere, check your electricity bill or use the Energy Networks Association postcode tool to confirm your DNO.
Each DNO runs its own online portal for G98 notifications and G99 applications. UKPN's portal is at connections.ukpowernetworks.co.uk. Your installer will register and submit there. As the homeowner you do not need a portal account, but you should ask for the submission reference number and the acknowledgement document once it arrives.
3. Gather what the form requires
The installer needs the following to complete either a G98 notification or G99 application:
- The property's MPAN number (on the electricity bill, a 13-digit number starting with a two-digit Profile Class code).
- The full address including postcode.
- The inverter make, model and rated export capacity in kW.
- The MCS installation certificate reference number.
- A single-line diagram showing how the system connects to the grid (the installer draws this).
- For G99: details of any protection relay settings, power factor settings and reactive power capability.
As the homeowner, your job is to make the MPAN available and to confirm the installation address. Everything else the installer prepares.
4. Submit the notification or application
For a G98 notification, the installer logs into the DNO portal, selects the G98 route, enters the system details and uploads supporting documents. The portal issues a reference number immediately, and the DNO sends a formal acknowledgement within a few working days. The notification must be submitted within 28 days of first energising the system.
For a G99 application, the sequence is reversed: the installer submits before installation begins, the DNO reviews the application (up to 45 working days by statute, often faster), and only then can the system be connected. If the DNO requires a modification to the protection settings or inverter configuration, the installer addresses that before commissioning.
Some DNOs have been slow to process G99 applications. If you are waiting for approval and the installer is pressing for a commissioning date, ask them whether a G98 route is permissible for your system size or whether there is an accelerated approval process.
5. Receive and file the acknowledgement
Once submitted and accepted, the DNO issues an acknowledgement document. For G98 this is typically a reference number and confirmation email. For G99 it is a formal letter or PDF confirming approval and any conditions.
File this document alongside your MCS certificate and the Electrical Installation Certificate (EIC) from the installer. You will need it in three situations:
- Smart Export Guarantee (SEG) registration: your licensed SEG supplier will ask for the DNO notification reference.
- Property sale: solicitors increasingly ask for the DNO notification as part of the solar panel legal pack, alongside the MCS certificate and EIC.
- Future modifications: adding battery storage to an existing solar installation, or increasing panel capacity, may require a fresh notification or amendment.
When to call us
Richard does not submit G98 or G99 notifications as a standalone service, but if you are getting solar panels or a battery storage system fitted and need the electrical supply assessment, consumer unit check or DC isolator wiring done to MCS standards, get in touch. We are also happy to look over the paperwork if something does not look right.
Getting solar panels or a battery fitted near Sandwich?
Richard can advise on supply capacity, consumer unit readiness and what the DNO notification process involves for your system.
Contact Richard