G99 Applications: A Plain-English Guide
If you are having solar panels or battery storage installed, you may have heard the term G99 application mentioned. It sounds technical, but the concept is straightforward. This guide explains what G99 applications are, when you need one, and how ALPS Electrical handles the entire process on your behalf.
What Is a G99 Application?
A G99 application is a formal request to your local Distribution Network Operator (DNO) — in the North East, this is Northern Powergrid — for permission to connect a generating system (such as solar panels) or energy storage system (such as a battery) to the electricity grid. It is a regulatory requirement under the Engineering Recommendation G99, which governs how distributed generation systems connect to the UK electricity network.
The purpose of the G99 process is to ensure that your solar or battery system will not adversely affect the local electricity network. Northern Powergrid needs to check that the local transformer and cables can handle the additional generation being fed back into the grid from your property.
When Do You Need a G99 Application?
You need a G99 application when your total inverter capacity exceeds 3.68 kW per phase on a single-phase supply, or 11.04 kW on a three-phase supply. In practical terms, this means:
- Small systems under 3.68 kW: Only require a G98 notification (a simpler process that your installer submits after installation).
- Systems between 3.68 kW and 50 kW: Require a G99 application, which must be submitted and approved BEFORE installation begins.
- Systems above 50 kW: Require an enhanced G99 application with additional technical studies.
Most residential solar and battery systems in 2026 exceed the 3.68 kW threshold, especially when combining a solar inverter with a battery system. A typical 4kW solar system with a hybrid inverter will require a G99 application.
How Long Does the G99 Process Take?
Northern Powergrid has 45 working days (approximately 9 weeks) to respond to a standard G99 application. In our experience, responses typically come back within 4-8 weeks. The response will be one of the following:
- Approval with no conditions: You are clear to proceed with installation. This is the most common outcome.
- Approval with conditions: You can proceed, but may need to meet specific technical requirements such as export limitation or power quality settings.
- Rejection or delay: This is rare but can happen if the local network is at capacity. In this case, Northern Powergrid may need to carry out reinforcement work before your system can be connected.
What Does ALPS Electrical Handle?
We manage the entire G99 process from start to finish at no additional charge. This includes:
- Determining whether your system requires a G98 notification or G99 application
- Preparing all technical documentation including single-line diagrams and system specifications
- Submitting the application to Northern Powergrid via their online portal
- Chasing the application if responses are delayed
- Reviewing and implementing any conditions attached to the approval
- Submitting the commissioning notification after installation is complete
You do not need to contact Northern Powergrid yourself or understand the technical details. We handle everything and keep you informed throughout.
Does the G99 Process Delay My Installation?
The G99 application must be approved before we can install your system, so it does add time to the overall timeline. We submit the G99 application as early as possible in the process — typically immediately after your survey and order confirmation. While we wait for the approval, we order your equipment and schedule your installation date. In most cases, the G99 approval comes through before the installation date, so there is no delay.
In cases where the approval takes longer than expected, we keep you updated and adjust the schedule as needed. We always give you a realistic timeline upfront so there are no surprises.
What Happens After Installation?
After your system is installed and commissioned, we submit a commissioning confirmation to Northern Powergrid. This formally registers your system on the network and allows you to export electricity under the Smart Export Guarantee. We handle this final step as part of our standard installation process.
Contact ALPS Electrical to discuss your solar or battery installation. We will explain the G99 process during your free survey and provide a clear timeline for your specific project.