Installing solar panels on your premises is an exciting opportunity to reduce your energy bills, increase your energy independence, and lower your carbon footprint.
Whether you’ve already installed them or are considering it in the future, having solar panels and batteries does come with legal considerations, notably a Distribution Network Operator (DNO) application.
At Apex Doma, we’re here to take you through submitting a solar DNO application. Our guide explains what a DNO is, why it’s needed, the different types, and how to achieve it in the most efficient, effective, and stress-free manner.
Key Takeaway Points
- A DNO application is required in the UK when registering energy devices connected to the national grid.
- DNO approval is needed to ensure that your local grid can support the additional electricity produced by your installation and reduce the risk of potential problems further down the line.
- The size and complexity of your solar system determine which DNO application to submit (G98 vs. G99).
- A DNO application is normally submitted by the person or company who installs your system.
- Using an MCS-certified provider, such as Apex Doma, means that you are not responsible for sorting out the DNO application.
What Is a DNO?
A Distribution Network Operator (DNO) is a company licensed to distribute electricity throughout the UK. They own and operate the system of cables and towers that transfers electricity to homes and businesses.
What Is the Purpose of a DNO?
The main purpose of a DNO is to distribute electricity from the national grid to people’s homes and businesses. They also look after the network of towers, transformers, poles, cables, and meters that deliver power to your premises and are responsible for dealing with power cuts.
During the DNO application, the DNO checks whether your local grid can accommodate the installation of your solar panels (i.e., can the network handle the extra power generated by your solar system, or are any upgrades needed?).
The DNO also checks that it’s safe to install your solar setup and that all technical and safety standards are met. This helps prevent issues such as voltage spikes or interference with other premises on the grid.
What is a DNO Application, and Why Do I Need One?
A DNO application is a formal request by your solar panel installer to your local electricity network operator, asking for permission to connect your solar panel or battery system to the national grid.
Whenever you connect any type of electricity generation device to the grid, you need to inform your local DNO.
Depending on the size and setup of your solar system, you may need to submit a DNO application before installation can begin, or submit a notification once they’re installed.
This is a legal requirement set by the UK government that requires customers and installation contractors to register energy devices in homes or small businesses.
Any installer registered with the Microgeneration Certification Scheme should be aware of this, but it’s worth knowing the following:
- For smaller systems (up to 16A per phase or 3.68 kW), your installer must inform the DNO within 28 days of commissioning.
- For larger systems (above 16A per phase or 3.68 kW), your installer will need permission from the DNO to connect to the grid. This may require a network study (at a cost) to ensure the local network is suitable for the power your system will produce. You’ll receive a quote for work within 45 days if the grid requires work to support your electricity.
Once your DNO application is approved, your DNO will send you a DNO letter.
What Is a DNO Letter, and Why Is It Important?
A DNO letter is confirmation that your solar system is either approved (for G99/G100 applications) or has been successfully notified (for G98 applications).
It’s an important document that proves your solar system is legally and safely connected to the grid. It may also be needed if you sell your home, apply for smart export payments, or switch your energy provider.
Types of DNO Applications
There are two main types of DNO applications in the UK for installing solar panels: G98 and G99.
What Is a G98 Application?
A G98 application is used in the UK to register small-scale electricity-generating systems, such as solar panels, with the local DNO. It applies to microgeneration systems up to 16 amps (3.68 kW) per phase and ensures compliance with Engineering Recommendation G98 standards.
A G98 application includes information about the:
- System type
- Capacity
- Inverter specifications
- Installer’s details
This notification ensures your local network can safely accommodate any additional power generated by your system’s installation without compromising the safety or reliability of others on the network.
What Is a G99 Application?
A G99 application is used in the UK to integrate microgeneration and electricity storage units that generate more than 16 amps (3.68 kW) per phase.
Similar to a G98, it’s required when connecting any device capable of generating electricity to the grid that exceeds the above threshold.
G98 vs G99: What Is the Difference?
The G98 application is simpler and quicker for systems below the 16-amp (3.68 kW) threshold per phase compared to larger installations, which require a G99 application.
More information is usually required for a G99 application, such as a signed letter of authority, site plans, and a connection design. This can come with additional costs, depending on the size and complexity of the system you’re installing.
Residential solar systems in the UK typically require a G98 application, as domestic systems tend to be smaller (under 16 kW) and are less likely to cause grid stability issues.
Thinking about getting a solar system for your premises? Check out our guide on the top 5 things to consider before buying solar and battery storage.
What Is a G100 Application?
A G100 application relates to the connection of distributed energy resources (DERs) in the UK to the national grid.
They’re designed to manage the export of electricity from renewable sources (such as solar) to the grid, especially when local network capacity is limited, or the system’s output exceeds the local grid’s safe handling capacity.
The DNO Application Process Explained
Who Is My DNO?
There are 14 district networks (DNO) regions in the UK, managed by just six operators. This makes it easy to work out which one is your DNO.
These are split into:
| Region | DNO | Website |
| North West England | Electricity North West | https://www.enwl.co.uk/ |
| North East, Yorkshire, Northern Lincolnshire | Northern Powergrid | https://northernpowergrid.com/ |
| Midlands, South West, South Wales | National Grid Electricity Distribution | https://nationalgrid.co.uk/ |
| London, South East, East of England | UK Power Networks | https://ukpowernetworks.co.uk/ |
| Merseyside, Cheshire, North Wales | SP Energy Networks | https://spenergynetworks.co.uk/ |
| Central & Southern Scotland | SP Energy Networks | https://spenergynetworks.co.uk/ |
| South Scotland, North West England | Scottish and Southern Electricity Networks (SSEN) | https://ssen.co.uk/ |
| Central Southern England | Scottish and Southern Electricity Networks (SSEN) | https://ssen.co.uk/ |
You can also enter your postcode to find your electricity network operator.
Top tip: Call 105 (free from most landline and mobile numbers) to be put through to your local DNO.
How Do I Get a DNO Letter?
To get a DNO letter, you must submit an application (usually a G98 or G99) to your local DNO. This is normally completed by whoever installs your electricity-generating device.
Steps to Getting a DNO Letter
- Identify your DNO: Enter your postcode on the Energy Networks Association website to find out who your operator is.
- Determine system type: Smaller systems (up to 16 amps or 3.68 kW per phase) require a G98, whereas larger systems need a G99 application before installation.
- Submit application: This is usually done by your MCS-certified installer.
- Receive letter: Your DNO will review your application and, if successful, issue a letter of non-objection (DNO letter).
What Information Do I Need When Applying for DNO Approval?
When applying for DNO approval, you’ll need to provide several pieces of information to ensure the system is assessed properly.
This may include (but is not limited to):
- Inverter specifications, such as make, model, power output, and capabilities.
- Generation capacity of your solar system.
- Grid connection details (e.g., how your solar installation will be physically connected to the grid and details on the connection point, such as whether it’s a single-phase or three-phase connection).
- System design showing the electrical layout of your solar system (including placement of solar panels, a wiring diagram, and any other electrical components).
When to Submit a DNO Application
The size and complexity of your solar system could affect when you need to submit a DNO application and which type of application is required.
You’ll likely need to submit a G99 application if your solar installation is over 3.68 kW. This should be done before your system is added to the network.
For smaller systems (i.e., those up to 3.68 kW), your installer must submit a G98 application. This can be done as a post-installation notification, but it must be sent within 28 days of completion.
How Long Does a DNO Application Take?
A DNO application can take anything from a matter of weeks to months, depending on the complexity of your case and the type of DNO application you’re submitting.
For example:
- A G98 is immediate, meaning no waiting is required (install the solar panels and then notify afterwards, which can take between 10 and 15 working days to process).
- A G99 application can take four to eight weeks for DNO approval, depending on the situation.
- A G100 application may require a more extensive review, especially if export-limiting equipment is involved.
Who Is Responsible for Submitting a DNO Application?
If you’re using a certified installer for your solar system, then they’ll manage the DNO application for you; you don’t need to apply yourself.
This includes identifying the required application type (G98 or G99), completing the paperwork, and submitting the DNO application or notification on your behalf.
Should you choose to manage the installation yourself, then you’d be responsible for submitting the DNO application.
It’s recommended to seek professional help from an MCS-certified installer when adding rooftop solar panels to your premises to ensure compliance with the law and a safe installation.
What Happens if I Install Solar Panels Without DNO Approval?
If you install solar panels without submitting a DNO application, then you could face several issues.
Firstly, you’d be breaking the law and would be liable for prosecution, as your DNO needs to approve your system to ensure it’s safe and won’t impact your local electricity grid network.
Secondly, without approval, you could have problems connecting to the grid. Your DNO could disconnect you if they find your system to be non-compliant, leading to wasted time and money. This could also invalidate your home insurance or cause issues when selling your property.
Failure to comply with the DNO approval process also means the rest of your installation is unlikely to meet the required standards.
There is an associated safety risk without proper DNO approval, which could lead to electrical hazards, including fires and electric shocks. The likelihood of system failure increases, as a poorly integrated solar system can cause voltage spikes or power surges, resulting in higher costs for you as the consumer.
How Much Does a DNO Application Cost?
The cost of a DNO application can vary depending on factors such as the size, scale, and complexity of the solar system, the area where it’s being installed, and the network’s existing capacity.
On average, the cost of a DNO application ranges from £50 to £500, with small-scale, simpler systems at the lower end and larger, more complex ones at the upper end.
Benefits of Getting DNO Approval When Installing Solar Panels
There are many benefits to getting DNO approval when installing a solar system on your premises.
- Legal compliance – In the UK, it’s a legal requirement to register energy devices with your local DNO. Failure to do so could lead to prosecution.
- Safety – It ensures that you meet regulations and reduce the risk of potential hazards, such as fires and electric shocks.
- Grid safety and stability – Your DNO can assess whether the local infrastructure can support excess energy production, reducing the risk of power surges and voltage spikes.
- Eligibility for export payments – A DNO application for systems over 3.68 kW per phase can help secure your Meter Point Administration Number (MPAN), allowing you to get paid for any excess electricity you produce.
- Smooth installation – Submitting a DNO application properly and early can prevent delays and ensure your system is integrated safely into your local grid.
- Saves you money – any issues can be identified and rectified before installation, meaning you haven’t wasted your money. You’re less likely to encounter safety concerns after a DNO approval, which can lead to fewer home insurance issues or problems when selling your property.
You can visit our Solar Advice Hub for the latest insights and research into solar energy in the UK, including further information on the DNO application process.
What Are the Problems Associated With a DNO Application (And How Best to Avoid Them)?
Technical limitations, outdated infrastructure, and administrative delays can be reflected in your DNO application. But, with the right approach, you can navigate these to ensure that your solar installation is as smooth, straightforward, and stress-free as possible.
- Grid capacity issue: Your local network may not be able to handle the additional electricity generated by your proposed installation. Consider downgrading to a smaller system or moving to an area with greater capacity.
- Significant delays in administrative processing: DNO approval times can range from weeks to months due to high application volumes. Submitting your application as soon as possible, with all required information, can help accelerate the process.
- Expensive reinforcement charges to the network: If your local grid needs upgrades to accommodate your system, there is a time delay before this work begins. You may also need to pay for these upgrades. Factoring this into your DNO application timeline can help manage your expectations.
- Incorrect or incomplete information: Your DNO application may stall or fail if it’s incomplete or if it’s found to be wrong at the time of submission. Checking your paperwork and ensuring you use a trusted, MCS-certified installer can reduce the risk of potential delays in your DNO application.
Can a DNO Application Be Rejected?
A DNO application can be rejected if your DNO feels that your solar system doesn’t meet the required standards or if there is a local issue with the grid. This means the installation of your system cannot proceed.
A rejected application usually means one of two things: either there is a safety concern with your proposed solar installation, or your local grid cannot handle further electricity generation.
If your DNO approval is rejected, then you can appeal the decision, provide additional information to support your application, or make adjustments to your system to ensure it meets the required DNO standards.
How Can Apex Doma Help With Your DNO Application?
Here at Apex Doma, we can help manage your entire DNO application for solar and battery installations, ensuring you’re fully compliant with UK grid regulations.
Whether it’s a G98 application for a smaller solar project or a G99 application for a larger installation, we’re here to do it for you.
All we require is for you to sign an authority form that allows us to contact your electricity provider on your behalf.
For a G98 application, we’ll submit a ‘connect & notify’ form to the DNO, so you can get your tariffs and Smart Export Guarantee (SEG) payments sorted as soon as possible.
Speak with one of our team members for a free, no-obligation quote to help find the solar solution that’s right for you.
Final Thoughts on Submitting a DNO Application
Installing solar panels or battery storage may seem like a big project. But with the right support and knowledge, it can be straightforward. This includes ensuring a DNO application is submitted correctly, so your system is connected safely and legally to the grid.
Our team of experienced, dedicated, and reliable experts is here to connect you with trusted, MCS-certified solar installers who’ll take care of everything, including your solar DNO application.
Contact us to arrange a virtual quote and address any queries you may have about your DNO approval or our range of other solar services.
FAQs About a Solar DNO Application
DNO stands for Distribution Network Operator.
A DNO approval is when a successful DNO application has been accepted by your local electricity network operator, granting you permission to connect your solar installation to the national grid.
To check your DNO approval status for solar and battery installations, contact your installer and ask for the G98 or G99 documentation, depending on which was submitted when your system was installed.
If you installed it yourself, contact your local DNO, which holds records of all grid-connected devices across the area it’s responsible for.
To get a DNO certificate for solar panels or battery storage in the UK, you need to submit a G98 or G99 application form via your local DNO.
If you’re using an MCS-certified installer to put in your solar system, then they should handle this for you. However, if you’re installing it yourself, then you’ll be responsible for ensuring this documentation is submitted in line with the law.
To find your DNO certificate, you should first check the handover documents provided when your installer fitted the solar system in question. If it’s not there, contact the installer directly and ask them to send it to you.
You can always contact your local DNO and reference your application number.
