All About DNOs

When you’re considering solar panel installation, whether you’re down south or you’re up in the sunny North East, you’ll inevitably encounter the term “DNO” during your solar power journey. However, we all know how confusing the more technical side of things can be – but understanding what DNOs are and how they impact your solar installation is crucial for a smooth transition to clean energy. At North East Solar, we guide our customers through every aspect of the solar installation process, including the essential DNO requirements that ensure your system operates safely and legally within the national grid.

What is a DNO?

A Distribution Network Operator (DNO) is a company responsible for owning and operating the electricity distribution network in a specific geographical area. Think of them as the keepers of the overall electrical infrastructure. Depending on where you are in the UK, there are different keepers. For example, here in the North East of England, Northern Powergrid serves as the primary DNO, managing everything from the vast network of power lines to the substations and transformers that not only keep the lights on, but more importantly, our kettles boiling across our region.

Why DNOs Matter for Solar Installations

When you install solar panels, you’re not just consuming electricity via the panels – whether you mean to or not, you’re also generating it. This fundamental change in your property’s relationship with the electrical grid requires careful coordination with your local DNO – and it’s not a bad thing! Solar panels feed excess electricity back into the grid through a process called “export,” which requires proper safety measures and technical approvals. It also puts that little bit of extra cash back into your pocket.

The purpose of the DNO is to ensure that your solar installation won’t negatively affect either the local electricity network or neighbouring properties. They assess factors such as voltage levels, network capacity, and safety protocols to maintain grid stability. Without proper DNO approval, your solar installation could face legal complications, safety issues, or problems with energy export payments.

DNO Application Process

Most residential solar installations in the North East require what’s called a G99 application, which is submitted to Northern Powergrid for systems generating up to 16 amps per phase. This application provides technical details about your proposed solar installation, including system capacity, inverter specifications, and connection arrangements.

The application process typically takes between 15 and 45 working days, depending on the complexity of your installation and current application volumes. During this period, the DNO reviews your proposal against network capacity, safety requirements, and technical standards. They may also request additional information or even suggest modifications to ensure compliance with grid codes.

For larger commercial installations or systems exceeding certain capacity thresholds, more comprehensive assessments may be required, including detailed network studies and infrastructure upgrades. At North East Solar, we handle all DNO communications on behalf of our customers, ensuring applications are completed accurately and efficiently.

Common DNO Requirements

Northern Powergrid, like all DNOs, has specific technical requirements that solar installations must meet. These include items such as proper earthing arrangements, appropriate protection devices, and, of course, compliance with engineering recommendation G99. Your inverter must have specific protection functions to disconnect safely in the event of grid problems, thereby protecting both your equipment and network infrastructure.

Installation certificates and commissioning documentation must be provided, demonstrating that qualified professionals have completed work to relevant standards. The DNO may also require witness testing of protection systems, particularly for larger installations or in areas with existing network constraints.

Export limitation may be imposed in some areas where network capacity is constrained. This means your solar system might need to be configured to limit the amount of electricity fed back into the grid, even if your panels could generate more. While this might seem restrictive, it ensures fair access to the network for all users while maintaining system stability.

DNO Timescales

Timeline management is crucial for solar projects, and DNO approval often sits on the critical path. Weather delays, application backlogs, and technical complexities can, unfortunately, also extend approval timeframes. We factor all of these variables into project schedules, keeping you thoroughly informed throughout the process.

Working with North East Solar

Here at North East Solar, we understand that DNO requirements can seem daunting for customers eager to begin their renewable energy journey. Our experienced team manages the entire DNO application process, from initial technical assessments through final approvals and commissioning.

We keep customers informed at every stage, translating technical requirements into plain English and managing timescales effectively.