Your local District Network Operator: Pointless, annoying, slow and necessary (sadly).
If you’re planning to install renewable energy devices such as solar PV, home battery storage, or an air source heat pump, you need to notify or apply to your Distribution Network Operator (DNO) before installation.
In this article, we cover the complexities of grid applications and notifications, providing a clear guide on how to navigate this process.
For those who prefer professional assistance, Heatable offers comprehensive support to manage the entire process on your behalf.
We offer home solar panel installation nationwide and handle the DNO application on your behalf. Simply answer these questions, get your fixed price and arrange your free design.
What is a DNO (Distribution Network Operator)?
DNO stands for Distribution Network Operator. These private entities are responsible for managing the power supplies in your local area, including maintaining the physical infrastructure such as powerlines and cables.
As of 2024, approximately 18 DNOs manage local power networks throughout the UK. Notable ones include UK Power Networks, Electricity North West, Scottish & Southern, and Manx Utilities.
A common misconception is that energy suppliers own the cables or infrastructure supplying your home. In reality, energy suppliers pay a fee to the local DNO, which owns and manages the infrastructure connecting power to your home.
If you are unsure who your DNO is and want to find out, then you can use the Energy Networks Association’s postcode checker.
What is a DNO application?
A DNO application for solar involves submitting forms to notify your local Distribution Network Operator (DNO) about the installation of solar panels at your home.
The specific forms you need to use will largely depend on the type of system you are installing, such as a small-scale domestic system or a larger commercial installation.
For instance, if you're installing a typical domestic solar PV system up to 16A per phase, you might need to submit a G98 form after installation.
For larger systems, you might need to submit a G99 form and obtain approval before installation.
Additionally, the timing of the application—whether it needs to be submitted before or after the installation—will depend on the specifics of the system.
For example, most domestic installations require post-installation notification, while larger or more complex systems may require pre-installation approval.
Who needs to make an application to a DNO?
Anyone looking to install a renewable generating device may require pre-approval. Regardless of whether pre-approval is necessary, every system must be notified to the Distribution Network Operator (DNO).
The application and notification process can be complex, so we recommend using a registered installer like Heatable to handle this on your behalf.
What is classified as a generating device?
A generating device is any equipment that generates energy. Examples include:
Solar power inverters
Battery inverters
Air source heat pumps
Ground source heat pumps
Wind turbines
How do you make a DNO Application?
While some Distribution Network Operators (DNOs) accept applications or notifications from private individuals, the process is complex, lengthy, and filled with regulatory requirements.
Heatable handles all applications on your behalf as part of our solar PV and home battery installations.
All DNOs follow the process outlined by the Energy Networks Association (ENA). The ENA stipulates:
Any generating device rated at 3.68 kW or below is classed as notifiable and does not require pre-approval (G98).
Devices rated over 3.68 kW require pre-approval and notification post-installation (G99).
Additionally, for systems over 3.68 kW but with restricted grid exporting to 16 amps per phase (3.68 kW), there is a G99 Fast Track option. This requires installing a G100 Energy Limiting System (ELS) simultaneously.
System Size | Application | Apply or notify | EST turnaround (working days) |
<3.68KW | G98 | Notify | 5 days |
>3.68KW (no export limit) | G99 | Apply | 45 days |
>3.68KW (with export limit) | G99 & G100 (ELS) | Apply | 10 days |
Any device you wish to apply for or notify must be approved by the Energy Networks Association (ENA). You can access the public register here.
For example, the Tesla Powerwall 3 has type test approval, and Heatable installs these at highly competitive prices—get your quote here.
If your product isn’t type-tested and approved by the ENA, your application will be declined by your DNO.
Still, learning about solar? Check out our guides on how many solar panels you need and how solar car charging works.
The DNO application process explained
To apply for DNO approval, you’ll need several documents, including:
The completed application form (relevant to your type of application)
A string line diagram (SLD)
Your MPAN reference (found on your energy bill)
Type test approvals for the products you want to install
Document Details:
Application Form: Find the required forms on the ENA website.
String Line Diagram (SLD): An electronic schematic of your installation’s wiring and setup.
MPAN Reference: Located at the top of your bill, usually starting with 'S'. Don’t confuse this with the meter serial number on your electricity meter.
Once you have all your documentation, submit your application to your DNO. They’ll acknowledge receipt and provide an estimated processing time.
Heatable handles all applications and notifications—get your fully inclusive quote online in 60 seconds.
Wondering how different solar installers compare? Check out our in-depth solar installer comparison here.
How much does a DNO application cost?
Every Distribution Network Operator (DNO) has its own processes. While all G98 notifications are free, other applications may incur charges.
Heatable includes application fees as part of our online fixed price promise—get your quote here.
We’ve installed 1000’s of systems and therefore have made 1000’s of applications.
Here’s a cost guide based on our own experiences:
System Size | Application | Cost to approve | Witness test fees (if applicable) |
<3.68KW | G98 | £0 | n/a |
>3.68KW (no export limit) | G99 | £150-£800 | n/a |
>3.68KW (with export limit) | G99 & G100 (ELS) | £100-£500 | £250-£1000 |
Can Heatable help with your DNO application?
Heatable includes the cost of applying for your DNO grid approval as part of our online quoting process—haven’t got your price yet? It takes less than 60 seconds.
We install solar PV, home battery systems, and air source heat pumps.
If you’re not using Heatable for your installation, use this guide and ensure a reputable installer makes the application on your behalf. Failure to do so can result in fines exceeding £10,000.
Explore a Solar Case Study: Check out an insightful Q&A session featured in one of our detailed case studies on domestic solar panels. Hear directly from a Heatable customer in the UK and gain valuable perspectives on their experience here.
The image above shows a 23-panel solar installation, carried out by the MCS-certified solar team at Heatable, featuring the REA Fusion2 solar panels.
Related solar guides:
Next Steps For Your Solar Journey:
When planning to install solar panels for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their solar installation.
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