If your business is considering installing solar panels, battery storage or another form of on-site electricity generation, you may come across the term DNO application during the planning process. For businesses unfamiliar with the electricity network, the DNO process can appear complicated.
What is a DNO? When do you need to make an application? How long does approval take? And what happens if your proposed system cannot be connected in its original form?
Understanding the DNO application process can help businesses plan their renewable energy projects more effectively and avoid unnecessary delays. In this guide, we explain what a DNO application is, when one may be required and why it is an important consideration for solar and battery storage projects.
What is a DNO application?
A DNO application is a request made to the relevant Distribution Network Operator (DNO) to connect a new electricity generating or energy storage system to the local electricity distribution network. The DNO operates and maintains the electricity network in a particular geographical area. When a business installs solar PV, battery storage or another generating technology, the DNO needs to understand how the proposed system could interact with the existing network. The purpose of the process is to ensure that new connections can operate safely and reliably without negatively affecting the wider electricity network; this is important where electricity may be exported from the property to the grid.
As part of the assessment, the DNO will consider factors including:
- The capacity of the proposed solar PV system
- The capacity of any battery storage system
- The property’s existing electricity connection
- The maximum amount of electricity that could be exported
- The proposed inverter and electrical equipment
- Protection and control arrangements
- The potential impact on the local network
- Whether network reinforcement may be required
When is a DNO application required?
Not every renewable energy installation will require the same DNO process. Whether a DNO application is required depends on the size and configuration of the proposed system, its connection to the electricity network and its potential export capacity. Smaller systems may fall under established notification or approval arrangements, while larger or more complex installations will require a formal application and technical assessment before they can be connected. A business will be looking at a much larger system than would be installed in a domestic property, meaning the DNO requirements are more involved.
One myth we have come across is the assumption that a system will not require DNO approval simply because the electricity generated is primarily intended for on site use. For example, a battery energy storage system can import electricity from the grid and discharge electricity back to it. The way the system is configured and controlled can therefore influence the requirements.
Why is a DNO application important for solar PV?
Solar PV generates electricity that can be consumed on site, stored in a battery or exported to the grid. For businesses with significant solar generation capacity, the potential for electricity export is a consideration. The DNO needs to understand how the proposed installation could affect the local network, including factors such as voltage and available network capacity.
A DNO application allows the network operator to assess the proposed connection and determine whether it can be accommodated safely. Getting this process right is important because a solar system should not just be installed and connected to the network without the appropriate approval or notification. If DNO requirements are overlooked, a project could face delays, additional costs or restrictions on how the system can operate. This is why grid connections at Harvest Green Developments are considered alongside system design, and shouldn’t be treated as an administrative step at the end of the project.
What information is needed for a DNO application?
The exact information required will depend on the type and size of the installation. For larger or more complex commercial projects, the DNO may request additional information or carry out further technical assessments. Accuracy is therefore extremely important. The details provided as part of the DNO application should reflect the system that is actually intended to be installed.
If the design changes significantly after approval, further communication with the DNO will be required.
A DNO application will require technical details relating to the proposed generation or storage system, including:
- Solar PV capacity
- Battery capacity
- Inverter specifications
- Maximum export capacity
- Electrical connection arrangements
- Protection settings
- Equipment specifications
- Site and meter information
- Proposed commissioning arrangements
How long does a DNO application take?
There is no universal timeframe for every DNO application. The time required will depend on the complexity of the proposed connection, the information required by the DNO and whether additional network assessment is necessary. A straightforward connection may be processed relatively quickly. Larger installations can take longer, particularly if the DNO needs to carry out network studies or determine whether reinforcement is required. This is why DNO requirements are considered early in the project. Waiting until equipment has been ordered or an installation date has been confirmed before starting the process could create unnecessary project risk.
We will keep you informed every step of the way on the DNO application as we submit it for your project and keep you updated on any feedback or required changes as we hear back from the DNO.
What happens if a DNO application is rejected?
A DNO may determine that a proposed system cannot be connected in its original configuration. However, this does not automatically mean the project has to be abandoned.
Depending on the circumstances, potential solutions could include reducing the system’s export capacity, changing the system design, introducing export limitation or considering network reinforcement. For example, a business may not need to export all of the electricity its solar panels or battery could potentially generate. An appropriately designed export limitation system may help control the amount of electricity sent to the grid.
The most suitable solution will depend on the individual site, electrical connection and requirements identified by the DNO. This is another reason why professional system design is important. We will consider the site’s energy consumption, generation requirements and grid connection limitations together.
DNO applications for battery storage
Battery storage is increasingly being considered by businesses looking to make better use of renewable generation and improve their energy management. A battery can store excess electricity generated by solar PV for use later, helping businesses increase the proportion of generated energy consumed on-site. However, battery systems can also interact with the electricity grid in different ways. Depending on the system design, a battery may charge from the grid and discharge electricity back into it.
For businesses considering solar and battery storage together, we would recommend assessing the grid connection requirements before finalising the system design. Understanding the permitted import and export arrangements will help ensure the proposed battery system is designed around both the site’s energy requirements and the available grid connection.
Can an installer complete a DNO application?
In many cases, a renewable energy installer or specialist electrical contractor can manage the DNO application on behalf of the customer; this is a step in the project we manage for all of our clients. This can remove the technical and administrative burden for businesses that do not have the specialist knowledge required to manage the process themselves and makes the process much less stressful for you.
When comparing renewable energy providers, it is therefore worth asking how they manage DNO applications and whether this is included within their project service. The ability to manage the grid connection process effectively can make a difference to the overall project experience and speed.
How can businesses prepare for a DNO application?
Businesses can make the process easier by providing their renewable energy installer with accurate information about the property and its existing electricity supply. Useful information includes electricity bills, meter details, existing generation equipment and information about the site’s current electrical connection.
It is also important to have a clear understanding of the business’s energy requirements. For example, knowing when electricity demand is highest can help inform the design of a solar and battery system and determine how much generation is likely to be consumed on site. The more accurately the system can be designed from the outset, the easier it is to establish the appropriate DNO requirements.
Choosing an experienced renewable energy partner
A DNO application is only one part of a solar or battery storage project, but it can have a significant influence on the project’s design, timescale and potential costs. Working with an experienced renewable partner means the DNO requirements can be considered alongside system design, energy consumption, battery capacity, export strategy and future energy requirements. For businesses investing in renewable energy, this joined up approach can help avoid treating the DNO process as an afterthought.
This illustrates that the right solution is about designing a system that works for the business, the building and the electricity network and not just installing the largest amount of panels as possible.
Frequently asked questions about DNO applications
What does DNO stand for?
DNO stands for Distribution Network Operator. A DNO operates and maintains the local electricity distribution network that delivers electricity to homes and businesses.
Do all solar PV systems need a DNO application?
No. The requirements depend on factors including the size of the system, its connection arrangement and its potential export capacity. Your installer will highlight which DNO application is most applicable and any associated costs based on the system size.
Does battery storage require a DNO application?
It can. The requirements depend on how the battery is connected and operated, including whether it has the ability to export electricity to the grid.
Can a DNO application delay a solar installation?
Potentially. Larger or more complex projects may require additional technical assessment, information or network reinforcement. Starting the process early can help reduce the risk of delays.
Who is responsible for a DNO application?
The exact arrangements depend on the project and the type of connection required and some renewable partners may require you to complete this step; however, we take the stress away and manage this process alongside all project steps.
What happens after a DNO application is approved?
The project can proceed in accordance with the conditions and requirements set out by the DNO. The installed system should match the approved design and connection arrangements, with any required commissioning or notification steps completed before operation.
Planning a solar or battery storage project?
Understanding the DNO application process is an important part of planning a renewable energy installation. Whether you are considering rooftop solar, ground mounted solar PV, battery storage or a combination of technologies, grid connection requirements should always be considered at the beginning of the project.
An experienced renewable energy specialist will determine the most appropriate system design and DNO route. By addressing the DNO application early, businesses can make more informed decisions, reduce the risk of avoidable delays and ensure their renewable energy system is designed to work effectively for their site and the wider electricity network.
