If you're installing solar panels that connect to the grid, you'll need to deal with a DNO application. Here's what that actually means and how the process works.
What Is a DNO?
DNO stands for Distribution Network Operator. In the UK, DNOs own and operate the local electricity distribution networks — the cables and infrastructure that carry electricity from the national transmission system to homes and businesses.
The UK is divided into licensed distribution network areas, each operated by a different DNO. The main ones are National Grid, UK Power Networks (UKPN), Scottish and Southern Electricity Networks (SSEN), SP Energy Networks, Electricity North West, and Northern Powergrid.
When you're installing a solar system that will export to the grid, you're connecting a generation asset to one of these networks. That's why the DNO needs to be involved.
Why Do You Need a DNO Application for Solar Panels?
The distribution network was designed primarily to carry electricity in one direction — from large power stations to end users. Solar panels change that dynamic by introducing generation at the local network level.
Before a solar system can be commissioned and start exporting, the DNO needs to be aware of it and, in some cases, approve it. This ensures the local network can handle the additional generation without causing power quality or safety issues.
Important: Failure to notify or apply to the DNO before commissioning is a breach of your connection agreement and can result in enforcement action or your customer being unable to register for export tariffs.
What's the Difference Between a G98 and G99 DNO Application?
G98 and G99 refer to the Engineering Recommendations that govern how small-scale generators connect to the distribution network.
For smaller systems (up to 3.68 kW per phase on single-phase connections). You notify the DNO before commissioning — you don't need to wait for approval.
Required for larger systems. You must submit the application and receive approval from the DNO before commissioning. Takes longer and requires more technical documentation.
Who Submits the DNO Application — the Installer or the Homeowner?
In practice, it's almost always the installer. While technically the responsibility sits with whoever is connecting to the network, homeowners don't have the technical knowledge to complete a DNO application correctly. Most DNOs expect the submission to come from the installing company.
This means every solar installer needs to either manage DNO applications themselves or use a specialist service to handle it on their behalf.
What Happens After the DNO Application Is Approved?
Once a G98 notification is accepted or a G99 application is approved, the DNO issues confirmation and — for export connections — an export MPAN or export number. This export number is what your customer needs to register for the Smart Export Guarantee (SEG) with an energy supplier.
Without the export number, your customer can't get paid for the energy they export, which is increasingly a selling point for solar installations.
How Much Does a DNO Application Cost?
The DNO itself doesn't charge for G98 notifications or straightforward G99 applications. Costs only arise if the DNO needs to upgrade the local network to accommodate the connection.
If you're using a submission service like ours, there's a fee for the service — but most installers find this saves significant time and reduces the risk of rejections and delays.
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