If you’re considering solar panels or battery storage for your home or business, you may come across a technical term: DNO application. At first glance, it might sound like yet another bit of red tape, but it’s a crucial step to ensure your solar installation runs safely, efficiently and legally.
At Sunlit Solar, we take care of this entire process for you. But here’s everything you need to know about it, and why it matters.
What Is a DNO?
DNO stands for Distribution Network Operator. These are the companies that manage the electricity grid in your area. There are several DNOs across the UK, and each one is responsible for ensuring that homes and businesses can safely connect to and export electricity back to the grid.
When you install solar panels (especially larger systems or ones with batteries), your system has the potential to send energy back into the network. The DNO must confirm your system won’t overload the grid or create instability.
Why Do You Need DNO Approval?
If your system is going to be connected to the grid, it must be either notified or approved by your local DNO. This ensures:
- ✅ The grid can handle the additional energy
- ✅ Your system is safe and compliant
- ✅ You can access Smart Export Guarantee (SEG) payments
- ✅ You don’t risk fines or a forced disconnection
If your installer skips this step, you could miss out on export payments or even be forced to disconnect your system.
G98, G99, and G100: What’s the Difference?
UK regulations break solar installations down into different categories:
- G98 – For smaller systems (typically under 3.68kW per phase). You can install first, then notify the DNO within 28 days.
- G99 – For larger systems or those with batteries. You need approval before installation.
- G100 – For cases where the local grid can’t handle full export, and a limiting device is used.
Whether you’re a homeowner with a 5kW system or a business installing a 15kW array, the correct process depends on your setup. Sunlit Solar will determine and manage this for you.
How Long Does DNO Approval Take?
- G98: No delay – just install and notify
- G99 & G100: Can take between 4 to 12 weeks, depending on your DNO’s workload
It’s one of the few parts of the process that can cause delays. That’s why our dedicated office team submit applications early and chase them regularly to keep your installation on track.
What’s a DNO Letter?
Once approved, your DNO will send a confirmation letter, which is proof that your system is officially registered. You may need this:
- To receive SEG (Smart Export Guarantee) payments (e.g. from Octopus or E.ON Next)
- When selling your home
- When switching energy suppliers
Don’t worry, we’ll send you a copy for your records and store it on file too.
What If the DNO Doesn’t Approve?
Rejections are rare. Occasionally, the DNO may require grid upgrades or export-limiting measures. If that’s the case, we’ll explain your options clearly, including any costs or delays, and work with you to find a solution.
Sunlit Solar Handles It All
From the moment you sign up, Sunlit Solar takes care of your DNO application. We:
- Determine whether you need a G98, G99 or G100 application
- Handle all paperwork and submit it on your behalf
- Track and follow up on progress
- Keep you informed every step of the way
We also ensure your system is installed by MCS-certified engineers, giving you peace of mind that every part of the process is safe, compliant and optimised for performance.
Final Thoughts
The DNO application may be technical, but you don’t need to worry about it. With Sunlit Solar, you get a smooth, end-to-end service that includes this crucial step, leaving you free to enjoy the benefits of clean, low-cost energy.
🌞 Thinking about solar? Let us handle the hard bits.
📞 Call us on 01458 834936 or email info@sunlit-solar.co.uk to start your solar journey today.