Are you looking into solar panels, a home battery, or a full energy storage system? If so, you may have come across the terms DNO approval or G99 application.
You might be thinking, “What on earth does that actually mean?” — and you are definitely not alone.
Grid regulations can feel like a maze of technical jargon at first. However, this guide breaks it down in a simple and straightforward way. As a result, you will clearly understand what happens behind the scenes of a professional solar installation.
First Things First: What is a DNO?
A Distribution Network Operator (DNO) is the company responsible for the electricity infrastructure in your region. This includes the cables, poles, and substations that deliver electricity to homes.
The simple difference:
- You pay your electricity bill to a supplier such as Octopus Energy, British Gas, or E.ON.
- In contrast, your DNO maintains the physical network that delivers electricity to your property.
There are six main DNOs across the UK, including UK Power Networks, National Grid Electricity Distribution, and SP Energy Networks.
If you’re unsure who your local operator is, you can use the
Energy Networks Association postcode lookup tool
to find out instantly.
Why Is DNO Approval Required for Solar Panels and Batteries?
When you install solar panels or a home battery system, you are not only taking electricity from the grid. In fact, you are often exporting excess clean energy back into it as well.
This is excellent for sustainability. However, it still needs to be carefully managed.
For example, if multiple homes export electricity at the same time, it can place strain on local infrastructure.
Therefore, the DNO has an important role. It ensures:
- Local cables are not overloaded
- Voltage levels remain stable
- The grid continues to operate safely and reliably
Related reading:
Solar PV Design & Consultancy Services
Learn more about systems and compliance here:
Solar Panels and Battery Storage Solutions
G98 vs G99 Explained: Solar Export Limits
The key difference between G98 and G99 comes down to one number:
3.68kW Export Capacity Per Phase
✓ G98 Process
For systems exporting up to 3.68kW:
- Install first
- Notify the DNO afterwards
- No prior approval required
- Typically faster to install
Think: Fit first, notify later.
⚡ G99 Process
For systems exporting more than 3.68kW:
- Apply to the DNO first
- Approval required before installation
- May include export limitations
- Additional grid assessment required
Think: Apply first, install later.
What Does the G99 Process Involve?
When you work with an experienced installer, they manage the entire process for you. Typically, it follows these steps:
1. System Design
Panels, inverter size, and battery configuration are designed for your property.
2. Application Submission
A technical application is sent to your local DNO.
3. Grid Assessment
The DNO reviews local network capacity and demand.
4. Decision
You will receive full approval, conditional approval, or a request for upgrades.
5. Installation & Commissioning
Once approved, installation can proceed safely.
How Long Does It Take?
- G98: Immediate notification after installation
- G99: Typically 2–4 weeks
- Up to 8 weeks in constrained areas
The “First Come, First Served” Reality
Grid capacity is shared locally and is not unlimited.
- Neighbouring systems can affect available capacity
- Local substations have finite export limits
- Earlier applications may secure better conditions
Therefore, early planning is always beneficial when considering solar or battery storage.
Do Home Batteries Need DNO Approval?
In many cases, yes.
A battery does more than store electricity — it can also export power back to the grid.
Because of this, batteries are assessed in the same way as solar systems.
If your system can export more than 3.68kW, a G99 application will usually be required.
Summary: We Handle Everything for You
You do not need to manage this process yourself.
A qualified MCS-certified installer will handle everything — from system design through to approval and commissioning.
- Fully compliant system design
- Safe grid connection
- Optimised long-term performance
Ready to Explore Your Options?
If you’re considering solar panels or battery storage and want to understand what your property can support, we can help.
Book a free home survey today. We will guide you through the best solution for your home, energy usage, and future plans.
