If you’re planning to install solar panels, you’ve probably come across the term “DNO solar application.” While it sounds technical, it’s an important part of many solar installations in the UK. A DNO solar application determines whether your local electricity network can safely accommodate the electricity your solar panels may export back to the grid.
Depending on the size of your system and whether you’re adding battery storage, approval may be required before installation can begin. The process works can help avoid delays and ensure your solar installation complies with UK regulations.
What is a Distribution Network Operator (DNO)?
A Distribution Network Operator (DNO) is the company responsible for managing the local electricity network in your area.
Unlike your energy supplier, who sells you electricity, the DNO owns and maintains the cables, substations and infrastructure that deliver electricity to homes and businesses. Their responsibilities include:
- Maintaining the local electricity network
- Connecting new properties and renewable energy systems
- Ensuring electricity can be safely imported and exported
- Preventing local network overloads
- Supporting the UK’s transition to renewable energy
Whenever a solar installation could affect the local network, the DNO needs to assess whether the connection is suitable.
What is a DNO Solar Application?
A DNO solar application is a formal request submitted to your local Distribution Network Operator to connect a solar PV system to the electricity grid. The application allows the DNO to assess:
- How much electricity your system may export
- Whether the local network has enough capacity
- Whether upgrades or restrictions are needed
- If the installation complies with engineering standards
In many cases, your solar installer will complete and submit the application on your behalf.
Why is a DNO Solar Application Necessary?
Although solar panels generate electricity for your property, any excess energy is usually exported back into the national grid.
If too many properties export electricity simultaneously, local electricity networks can experience voltage issues or become overloaded. A DNO application helps ensure:
- The electricity network remains stable
- Neighbouring properties are not affected
- Renewable energy can be connected safely
- Your installation meets UK engineering regulations
Without the correct approval where required, your installation may not comply with industry regulations and could face delays or require alterations.
When Do You Need a DNO Solar Application?
Not every solar installation requires prior approval. Whether you need a DNO solar application depends on the size and export capacity of your system.
Small Domestic Installations (G98)
Many smaller domestic solar systems fall under the G98 process. These systems generally don’t require approval before installation. Instead, your installer notifies the DNO after the system has been commissioned. This route is designed for smaller microgeneration systems that meet specific export limits.
Larger Solar Systems (G99)
Larger systems usually require a G99 application. This means approval must be obtained before installation starts. Examples include:
- Larger residential solar arrays
- Commercial solar installations
- Systems with higher export capacities
- Solar combined with large battery storage systems
- Three-phase installations
Your installer will calculate whether your project falls under G98 or G99.
Common Situations That Require a DNO Application
You may need a DNO solar application if you’re:
- Installing a large solar PV system
- Adding battery storage that exports electricity
- Expanding an existing solar installation
- Increasing your inverter capacity
- Installing solar panels on commercial premises
- Connecting renewable technologies that significantly export electricity
Every property is different, so your installer should assess the requirements before work begins.
The DNO Solar Application Process
The process is usually straightforward when handled by an experienced installer.
1. Site Survey
Your installer assesses:
- Roof size and orientation
- Proposed system size
- Inverter specification
- Expected export capacity
2. Preparing the Application
The installer submits technical information including:
- System design
- Single-line electrical diagrams
- Equipment specifications
- Export calculations
- Property details
3. DNO Assessment
The DNO reviews whether the local electricity network can safely support the proposed installation. If necessary, they may request additional information or suggest changes.
4. Approval
Once approved, installation can begin (for G99 systems). For G98 systems, notification is usually sent after installation.
How Long Does a DNO Application Take?
Timescales vary depending on:
- The DNO serving your area
- The complexity of the installation
- Network capacity
- Whether upgrades are required
Straightforward domestic applications are often processed within a few weeks, while larger commercial projects may take longer. Submitting complete and accurate documentation can help avoid delays.
What is a DNO Connection Agreement?
In some cases, the DNO will issue a connection agreement. This document sets out the conditions under which your solar system can connect to the electricity network. It may include:
- Maximum permitted export capacity
- Technical requirements
- Any network limitations
- Conditions that must be met before connection
Your installer should review the agreement with you and ensure the installation complies with its requirements.
Common Challenges During the DNO Application Process
Most applications are approved without major issues, but some challenges can arise.
Limited Network Capacity
Some areas already have high levels of renewable generation. If the local network is approaching capacity, the DNO may:
- Restrict export levels
- Request equipment changes
- Recommend network upgrades
Missing Information
Incomplete applications often lead to delays. Providing accurate technical documentation helps the DNO assess your application more efficiently.
Installation Changes
If you decide to increase the system size after approval, another application may be required. It’s usually better to finalise the design before submission.
How DNOs Support Renewable Energy
As more homes install solar panels, battery storage and electric vehicle chargers, DNOs play an increasingly important role. They help:
- Connect renewable technologies safely
- Modernise the electricity network
- Improve grid resilience
- Enable greater use of clean energy
- Support the UK’s journey towards net zero
Many DNOs are investing heavily in smarter networks that can better manage renewable electricity generation in the future.
Frequently Asked Questions
Do all solar panels need a DNO application?
No. Smaller systems may only require notification under G98, while larger systems generally require approval through G99 before installation.
Who submits the DNO application?
In most cases, your MCS-certified solar installer will complete and submit the application for you.
Can I install solar panels before DNO approval?
If your installation requires a G99 application, approval should normally be received before installation begins.
Does battery storage affect a DNO application?
Yes. Batteries that can export electricity may increase your system’s export capacity and could require a different type of DNO application.
Will a DNO refuse my application?
Most applications are approved. However, if the local electricity network has limited capacity, the DNO may apply export limits or recommend network upgrades.
Choosing an Experienced Solar Installer
An experienced installer will assess whether your project requires a DNO application and manage the entire process on your behalf. This includes:
- Designing a compliant solar system
- Preparing all technical documentation
- Liaising with the DNO
- Managing any approval requirements
- Ensuring your installation meets UK regulations
Working with an accredited installer helps minimise delays and gives you confidence that your system is connected safely and correctly.
What does this mean?
A DNO solar application is an important part of many solar installations, ensuring your system can safely connect to the local electricity network without affecting grid stability. While not every installation requires prior approval, larger systems and those with higher export capacities often do.
The difference between G98 notifications and G99 applications can help you plan your project with confidence. If you’re considering solar panels, speaking with an experienced installer early in the process will help determine whether a DNO application is needed and ensure everything is handled correctly from the outset.