There are all sorts of things you need to consider when you’re installing solar panels. Where are you buying them, and who are you having install them? What direction should they face, what maintenance do they need, and how much should you pay?
Besides that, though, there’s one consideration you may not be aware of. Your installer is likely to need to complete a DNO application in order for you to have them installed. But what is a DNO application and how do they make one?
That’s what this guide is all about.
What is a DNO (Distribution Network Operator)?
A Distribution Network Operator, or DNO, is a company that owns a part of the physical infrastructure of the electrical grid. That includes the power lines, cables and substations that bring energy from power plants to your home.
There are lots of different DNOs in the UK. Your installer will handle the application for you, but it’s good to know the different types available.
The one that maintains the distribution network around London, the South East, and the East of England is UK Power Networks, which also happens to be the biggest; the other DNOs in the UK are:
- SP Energy Networks, which covers the Lowlands of Scotland including Glasgow, as well as North and Mid Wales, Merseyside, Mid Cheshire and the Wirral.
- Scottish & Southern, which covers the Highlands and Islands of Scotland, as well as the south of England in Hampshire, Dorset, Wiltshire, Gloucestershire and Oxfordshire. They are also responsible for the Isle of Wight.
- Western Power Distribution, which covers the South West up to Gloucestershire, South Wales, and the East and West Midlands coast-to-coast.
- Electricity North West, which covers the North West from the Scottish border to the area south of Greater Manchester. Northern Powergrid, which covers the North East from the Humber to the Scottish border.
- Northern Ireland Electricity Networks, which covers Northern Ireland.
- Manx Utilities, which covers the Isle of Man.
If you aren’t sure who your DNO is, you can find out through the Energy Networks Association’s postcode checker.
What is a DNO Application?
A solar DNO application is where a form is submitted to your DNO to notify them that you’re having solar panels installed. There are a few different forms, and which one to submit depends on the panels you have installed. In some instances, the forms should be submitted before installation, while in others, they should be submitted after.
Why are DNO Applications Necessary?
Your solar system will be connected to the grid, and when any kind of energy-generating technology is connected to the grid, it can cause voltage spikes. This in turn could cause issues like flickering lights or even tripping the network and cutting off supply.
If the proportion of houses generating solar energy increases, as it should if the country meets green energy targets, this could pose significant issues in local supply. It’s every DNO’s responsibility to prevent issues like these, and in the case of solar installations, requiring a DNO application is how they do it.
Do I Need to Make a DNO Application?
According to the UK Government website, if you are installing an energy device such as a solar system in your home, you are required to register it with your DNO. This previously wasn’t necessary, and as such, you may encounter conflicting advice online. However, your installer will take care of the application, should you need one.
The DNO Application Process
DNO applications aren’t simple, but they are defined by government guidelines. There are many steps to follow and forms to fill in when sending a DNO application form, but the official process is set out in clear terms, so it’s more long-winded than difficult. The good news is that through the Solar Together scheme, your installer will take care of all of the necessary steps for you. Find out how the scheme works here.
Step 1: Find an installer that is appropriately registered
Your DNO will require that your solar panel installer is either registered with a Competent Person Scheme, or certified through a certification body. Your installer of choice will be able to show you that they are appropriately registered, in the same way as a gas engineer can show that they are Gas Safe registered.
Finding a suitable installer is easy if you work with Solar Together. We have pre-approved installers that we work with, all of whom are fully certified, meaning that everything is arranged for you.
Step 2: Check with your installer if your DNO application is ‘connect and notify’ or ‘apply to connect’
Depending on your solar panels, you will either need to inform the DNO before or after you have them installed. If your panels fall under ‘apply to connect’, then you need to send an Engineering Recommendation (EREC) G99 DNO application form to your DNO; or if export is limited, a G100, and if battery storage is being implemented alongside the panels, a G99 A1-2 form for connection of Fully Type Tested Integrated Microgeneration and Storage Installations.
Is it G98 or G99 though? If your system is smaller than 3.68kW, you will require a G98 DNO application. This is known and as ‘connect and notify’ application and means it can take place once the system is installed.
If your system will be more than 3.68kW, you will need a G99 DNO application. This is known as an ‘apply to connect’ application and needs to be approved before installation. Your installer will be able to advise you on which DNO application they will be undertaking for you. However, if you are interested in calculating the kW size of your system, you can multiply the number of panels by the individual panel wattage and divide by 1,000 (i.e. 8 panels x 380W = 3,040. 3,040/1,000 = 3.04kW system).
Step 3: Install your solar panels
Next, the panels are to be installed alongside any storage battery, EV charge point, or additional add-on you have planned. Installation typically takes one day, or two days for a large number of panels. Bear in mind that some energy efficiency schemes may require application before installation. For example, if you can install a large system requiring a G99, you need to be prepared to wait for the approval which would in turn postpone your installation until this is approved. Furthermore, you need to have a conversation with the installer if such a large installation is necessary when compared to your electricity demand.
On the other hand, if you want to stick to a system not greater than 3.68kW, the yearly generation of this system (in normal circumstances reaching ~3300 kWh a year) could match your electricity usage most of the time.
Installing a larger system would make more sense when paired with a specific battery size which would enable you to store energy for evening use and export less during the daytime. In this case, it may be worthwhile applying and waiting for G99.
Contact Solar Together for More Information
If the phrases ‘ensuring compliance’, ‘application form EREC G99’ and ‘distribution network’ fill you with dread, you’re not alone. But don’t let technical issues stand between you and a green future, these are things that your solar installer will take care of, should it be necessary, for your installation.
If you're interested in having solar panels installed, Solar Together can help. We offer group-buying discounts on solar panels and batteries. Our scheme works by aggregating the demand for solar panels and batteries from households in a local area. By pooling this demand, we're able to negotiate group-buying discounts with suppliers, making solar panels and batteries more affordable for everyone.
Even better, we vet appropriately registered suppliers for the quality of their service so that you don't have to. Beyond that, we even offer optional add-ons like battery storage and EV charge point installation and insurance-backed guarantees for customer protection.
We understand why that might sound too good to be true. So, why not learn more through our Blog?