DNO Costs and Processes explained

DNO applications are needed when installing solar PV panels, battery storage where the battery has a back up or “islanding” functionality, heat pumps, and EV chargers.

You MUST apply for the DNO before installing your system.

There are basically 3 types of DNO for solar PV:
G98 – for systems if the generation is more than 16A per phase which is the equivalent of 3.68kW for a single phase supply or 11.04kW for a three phase supply.
G99 -for larger systems up to 50kW or systems if the generation is more than 16A per phase

G100 - if your G99 application comes back and your system’s export needs to be limited, a G100 application is required.

Your installer should undertake the DNO application for you.

After your DNO application has been assessed, you will usually be sent something called a “connect offer”. This includes the maximum specification of the connection and if there are any connection charges.

There are usually three outcomes of a DNO application.
1. Your application is accepted, and your DNO is happy with the size of the system you have requested to install. This means you can proceed with your installation, with no extra charges or amendments.
2. The system size is capped at a given kWp AC rating, and an export limitation is required. Sometimes a small fee is charged for a “witness test”, where your provider ensures a limitation has been put in place.
3. Your supply size needs to be upgraded from a single phase to a three phase system in order to go ahead with your solar panel installation. This additional charge can be pricey depending on the site.
In the event that the DNO declines your application to connect, it could be necessary to install an export power management system to limit the electricity from the PV system to the grid.

HOW MUCH DOES A DNO APPLICATION COST?
The G98 DNO application for “connect and notify” is a free application, however administrative fees from your solar panel installers are usually charged in order to process the application. As for the G99 and G100 applications, they can cost anywhere between £300 – £750 each depending on the network.

HOW LONG DOES A DNO APPLICATION TAKE?
Due to the recent demand in domestic renewable energy, waiting periods for DNOs have increased and while there are no delays for G98 due to the nature of the application, G99 and G100 requires an application and approval before any installation can be done, and you can expect it taking 8-12 weeks and in some cases up to 4 months.

For the typical G99 domestic type A installation, abbreviated or fast-track applications are available from your DNO.

G99 will require commissioning documents to be submitted to the DNO after an installation was commissioned.

For larger G99/G100 compliant systems, the DNO may require feedin limiting devices to be fitted which could be costly in terms of the hardware and the DNO's involvement.

G99 will require commissioning documents to be submitted to the DNO after an installation was commissioned.

For larger G99/G100 compliant systems, the DNO may require feedin limiting devices to be fitted which could be costly in terms of the hardware and the DNO's involvement.