G98 vs G99: Which Grid Connection Do You Need?

When planning a solar panel and battery storage system in the UK, one of the most critical steps happens before a single panel goes on your roof: notifying the grid.

Because your new solar inverter will be capable of sending electricity back into the National Grid, your local Distribution Network Operator (DNO)—the company responsible for the power lines in your area—needs to ensure the local infrastructure can handle it. This is done through either a G98 or a G99 application. Here is what you need to know before you buy your equipment.

What is a G98 Application? The G98 process is for smaller, standard domestic systems. Specifically, it applies if your solar inverter's maximum export capacity is 16 Amps per phase, which equals 3.68kW, or less.

• The Benefit: Under G98, your certified installer can simply install your system and notify the DNO within 28 days after commissioning. You do not have to wait for permission to get your solar running.
• Best for: Standard 3.6kW single-phase hybrid inverters.

What is a G99 Application? If you want to install a larger system to combat high energy bills, such as a 5kW, 8kW, or larger inverter, you will likely exceed the 3.68kW export limit. In this case, you must apply under the G99 regulation.

• The Rule: You or your installer must submit a G99 application and wait for approval from the DNO before you install the system.
• The Timeline: Approval can take anywhere from a few weeks to a couple of months depending on your local network.

Why Battery Storage Matters Many homeowners get caught out here. The DNO looks at the total potential export of your inverter, not just your solar panels. Even if you install export limitation software, which prevents your system from sending more than 3.68kW to the grid, you may still require a G99 application if the inverter itself is rated higher, for example a 5kW hybrid inverter.

The Verdict Always check your property’s energy demands before choosing an inverter. If you want a quick installation, stick to a 3.6kW single-phase inverter. If you are building a larger system with electric vehicle charging and high-voltage battery storage, plan ahead and get your G99 application started early.

Ready to find the right equipment? Browse our range of Single-Phase Hybrid Inverters and Three-Phase Hybrid Inverters to match your DNO requirements.