What is a DNO application, and why do I need one?
What is a DNO application? A DNO application is an official request to your local Distribution Network Operator (DNO) for authorisation to connect a new energy system, such as commercial solar panels, to the UK electricity grid.
You need a DNO application because it guarantees your installation is safe, compliant, and will not negatively affect the local power supply. Without approval, your system won’t legally be connected to the grid.
The UK is divided into 14 ‘districts’, each with its own MPAN (Meter Point Administration Number) prefix, and is run by one of 6 DNOs as listed below:
| MPAN Prefix (Distribution ID) | Area | Operator |
| 10 | Eastern England | UK Power Networks |
| 11 | East Midlands | National Grid PLC |
| 12 | London | UK Power Networks |
| 13 | Merseyside & Northern Wales | SP Energy Networks |
| 14 | West Midlands | National Grid PLC |
| 15 | North Eastern England | Northern Powergrid |
| 16 | North Western England | Electricity North West |
| 17 | Northern Scotland | Southern & Scottish Energy |
| 18 | Southern Scotland | SP Energy Networks |
| 19 | South Eastern England | UK Power Networks |
| 20 | Southern England | Southern & Scottish Energy |
| 21 | Southern Wales | National Grid PLC |
| 22 | South Western England | National Grid PLC |
| 23 | Yorkshire | Northern Powergrid |
MPANs for Electricity explained:
An MPAN is a 21-digit number that uniquely identifies your electricity meter and is divided into two lines of information, as shown in the graphic above.
The top line contains technical codes that help your energy provider and DNO recognise how electricity is used and should be charged:
Profile Class: A 2 digit number that divides consumers into 1 of 9 categories based upon consumption and load profile. These consumption patterns monitor patterns in usage to help manage the network and provide better services.
00: Non-Domestic Customers with peak load usage above 100 kW.
01: Domestic Unrestricted Customers.
02: Domestic Economy 7 Customers. E7 customers have cheaper electricity rates at night.
03: Non-Domestic Unrestricted Customers.
04: Non-Domestic Economy 7 Customers. E7 customers have cheaper electricity rates at night.
05: Non-Domestic Maximum Demand Customers with a Peak Load Factor of less than 20%.
06: Non-Domestic Maximum Demand Customers with a Peak Load Factor between 20% & 30%.
07: Non-Domestic Maximum Demand Customers with a Peak Load Factor between 30% & 40%.
08: Non-Domestic Maximum Demand Customers with a Peak Load Factor over 40%.
Meter Time Switch Code:
States how many registers your meter has and what times they operate. If your meter has 2 registers, it will also show what times they operate.
Line Loss Factor:
Describes the expected cost that a DNO charges a supplier for use of their cables and electricity network. It also indicates the possible charges a supplier may face due to the loss of energy that occurred during the process of getting the electricity to your meter.
The bottom line contains the primary 13 digits of your MPAN, it identifies which area you are in, a unique number to identify your electricity supply point and a check digit.
✅ Distribution ID: A 2-digit number assigned to each District.
✅ Meter Point ID Number: A unique (per district) 8-digit number that identifies the physical metering point.
✅ Check Digit: 3 digits that validate the previous ones through a formula to prevent errors during data entry or supplier transfers.
G98 vs G99
G98 and G99 are UK regulatory standards governing the connection of solar PV systems and battery storage to the national grid. Under G98, systems up to 3.68kW per phase (or 16A per phase) can be connected, making it suitable for most domestic installations. For any system exceeding these limits, G99 compliance is required.
The G98 application process follows a 'connect and notify' system, allowing installation to continue immediately with notification to the Distribution Network Operator (DNO) upon completion. On the other hand, G99 requires prior approval from the DNO before installation can begin, a process that can take several weeks. G98 approvals are typically immediate, whereas G99 applications involve a waiting period to guarantee the grid can accommodate the additional load.
There is also a significant difference in application costs. G98 applications are generally free of charge, while G99 applications typically incur a fee, often ranging from £300 to £750. Approval for a G99 application can take anywhere between 10 & 45 working days, depending on the difficulty of the application as is usually best handled by an expert provider, such as Excel Energy UK.
Creating an income stream from surplus Selling Energy
In the UK, businesses with solar PV systems or other renewable technologies can generate extra revenue by exporting surplus electricity back to the national grid through the Smart Export Guarantee (SEG).
Under this government-backed scheme, accredited energy suppliers must compensate small-scale renewable generators for each unit of electricity exported.
At Excel Energy, we guide our clients through the process of system registration, metering, and compliance to insure they maximise the financial benefits of their commercial solar installations while contributing to a more resilient energy infrastructure.
Here’s how you can maximise income:
Integrate battery storage
Installing a commercial-grade battery storage system allows you to capture excess solar generation during peak sunlight hours and utilise this stored energy during periods of low generation or peak demand, considerably reducing reliance on grid-supplied electricity.
Improve on-site energy consumption
Schedule high-energy processes and equipment operation, such as industrial machinery or HVAC systems, to coincide with periods of maximum solar generation. This reduces grid import requirements and maximises the direct use of self-generated renewable energy.
Register for an export tariff
By registering in an appropriate SEG export tariff with an accredited supplier, you can make money from surplus electricity exported to the grid, generating a further revenue stream for your business.
The outcomes of a DNO application
After your DNO application has been received and assessed, the Distribution Network Operator can either accept your system connection as is, reject the proposed installation (though outright rejections are extremely rare), or they will impose what is known as “export limitation” In the first and third cases, you will be sent a connection offer. This includes any limitation figures of the connection and whether there will be any connection charges.
Further details of these outcomes are listed below:
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: Your application was rejected
and the DNO will not allow your equipment to connect to the grid. But categorical rejections are rare and it is more likely that some additional works are required to be performed to either limit the AC output of the inverter or you will need to pay to upgrade some of the local infrastructure, as seen in points 3a and 3b:
3A: The system size is capped
at a given kWp AC rating, and an export limitation is required, (detailed below). Sometimes, a small fee is charged for a witness test, where your provider ensures a limitation has been put in place to protect the local infrastructure.
3B: Your supply size needs to be upgraded
from a single phase to a three-phase system to go ahead with your solar panel installation. This additional charge can vary greatly depending on the works required.
Export limitation is applied through a 3rd type of application called a “G100”, which costs an additional £300-750 and is typically achieved through fitting an export limitation device to an inverter’s AC output, though a majority of modern inverters also have this functionality built in.
DNO Applications can seem very daunting and complicated, but with a little help from a trusted renewables supplier such as Excel Energy UK Ltd, this process can mostly be handled for you, with only a little information required from you. Contact Excel Energy to start your journey into a greener, more reliable future