Free DNO Application Checker
Check whether you need a G98 notification or G99 application for your solar, battery, or generation installation. Enter the installation postcode and system details to find your DNO and understand the process.
Automate DNO applications in Payaca
Submit G98 and G99 applications directly from each job via ENA Connect. Track status and get notified when approvals come through.
DNO Application Checker
Check whether you need a G98 notification or G99 application
See DNO tracking running inside a real install
A 20-minute walkthrough showing G98 and G99 status, MCS handover packs, scheduling and payment, all stitched into one Project record.
A DNO application checker helps UK solar and clean tech installers determine whether a generation connection requires a G98 notification or G99 full application under the Engineering Recommendations published by the Energy Networks Association (ENA). The decision depends on the total generation capacity at the property and the phase type of the electrical supply. In Payaca, DNO applications are integrated directly into your workflow via ENA Connect, with automatic status tracking and notifications. For compliance documentation including MCS certificates and handover packs, see our compliance features.
G98 vs G99: How it works
When connecting generation equipment (solar panels, batteries, wind turbines, etc.) to the UK electricity grid, installers must either notify or apply to the local Distribution Network Operator (DNO). The process depends on the total generation capacity at the property.
G98 (notification): For systems up to 3.68 kW on a single-phase supply or 11.04 kW on three-phase. You install first and notify the DNO within 28 days of commissioning. There is no fee, and the DNO typically responds within 4 weeks.
G99 (full application): For systems above the G98 thresholds. You must apply to the DNO before installing. The DNO assesses the impact on the local network and may require grid reinforcement works. Assessment fees range from £500 to £2,500 depending on DNO and project complexity, and the process typically takes 8–12 weeks.
Cumulative capacity: These thresholds apply to the total generation at the property. If a site already has 2 kW of solar panels and you're adding 2 kW more, the combined 4 kW exceeds the 3.68 kW single-phase threshold, so a G99 application is required even though the new installation alone would be under the limit.
Battery storage: Assessed on the inverter rating (maximum export power in kW), not the battery capacity in kWh.
G99 Fast Track: Crossing the G98 threshold does not always mean a full assessment. EREC G99 carries a Fast Track process for Small Generation Installations up to 60 A per phase, which DNOs turn round in around 10 working days rather than 45–65. It is assessed on registered (exportable) capacity, not the inverter's design capacity, so a larger inverter with a factory-set export limit can stay on the notification-only route. G98 vs G99: what decides which one you need has the full comparison, the three SGI categories and the forms each one takes.
What happens after you apply
A G98 notification is usually acknowledged automatically. A G99 goes into an assessment queue, and the answer that comes back is rarely a simple yes or no. These are the outcomes worth planning for, because two of them look similar and mean completely different things for the install date.
Approved. The connection can go ahead as designed. Once the system is live you still owe the DNO a commissioning confirmation, and the job is not closed until that is accepted.
Approved with an export limit. The installation is allowed, but capped on what it can export. This is common on constrained parts of the network, and an export limitation scheme under G100 is often what keeps a larger job alive rather than refused.
Further information required. A paperwork problem. The DNO wants a detail you almost certainly already have, and a quick reply clears it. Most of the delay here is the time it takes someone to notice the request.
Works required. A network problem. The DNO has decided their equipment needs upgrading before your system can connect, and there is nothing on your side to fix. What the status means and what to do while you wait covers how to handle the customer conversation.
Rejections are worth avoiding rather than appealing, because a resubmission goes to the back of the queue. The most common causes of failed G99 applications are almost all things you can check before you submit.
Related guides
Grid connections
Payaca submits G98 and G99 applications through ENA Connect from inside the project, polls for status changes, and files the commissioning against the same job. See grid connections for how it fits together, or software for UK solar installers for the wider picture.
Frequently asked questions
What is the difference between G98 and G99?
G98 is a simple notification process for smaller installations (up to 3.68 kW single-phase or 11.04 kW three-phase). You install first and notify your DNO within 28 days. G99 is a full application process for larger systems. You must apply to your DNO and receive approval before starting the installation. G99 involves an assessment fee (typically £500–£2,500) and takes 8–12 weeks.
What is a DNO?
A Distribution Network Operator (DNO) is the company responsible for maintaining the local electricity distribution network in your area. There are six DNOs covering Great Britain (plus NIE Networks in Northern Ireland). When connecting generation equipment like solar panels or batteries to the grid, you must notify or apply to the relevant DNO.
How long does a G99 application take?
A typical G99 application takes 8–12 weeks, but complex cases or those requiring grid reinforcement can take up to 6 months. The DNO has 45 working days to provide a connection offer once they have all the required information. Assessment fees range from £500 to £2,500 depending on DNO and project complexity. Grid reinforcement, if required, is an additional cost.
Is there a faster route than a full G99 application?
Yes. EREC G99 includes a Fast Track process for Small Generation Installations, run by DNOs as a separate queue. There are three categories: SGI-1 (total registered capacity up to 16 A, notification only on Form A3-3), SGI-2 (total up to 32 A with export limited to 16 A) and SGI-3 (each unit up to 32 A, total up to 60 A per phase, with export limited to 32 A). Every unit must run through a G98 or G99 type tested inverter and sit in a single generator's installation. SSEN aim to respond within 10 working days, after which you have three months to install and commission.
Is the threshold based on the inverter size or the export limit?
The export limit. G98 and G99 thresholds are assessed on Registered Capacity, which is what the installation is permitted to export, not Intrinsic Design Capacity, which is what the equipment is built to produce. A 7.36 kW inverter with a manufacturer's factory-set export limit of 3.68 kW is assessed at 3.68 kW. This is why reading the headline figure off a datasheet can send an otherwise notification-only job into a full application it did not need.
How is battery storage assessed?
Battery storage is assessed on its inverter rating (maximum export power in kW), not the battery capacity in kWh. For example, a 10 kWh battery with a 3.6 kW inverter would be assessed as 3.6 kW for G98/G99 purposes.
What does cumulative capacity mean?
G98 and G99 thresholds apply to the total generation capacity at a property, including any existing solar, battery, or other generation equipment already connected. If a property already has 2 kW of solar panels and you want to add 2 kW more, the total 4 kW exceeds the 3.68 kW single-phase G98 threshold, requiring a G99 application.
What is export limiting (G100)?
G100 is not a separate application type. It refers to an export limiting device that a DNO may require as a condition of approving a G98 or G99 application. This is common in areas where the local grid has limited capacity for additional generation. The device limits how much power your installation can export to the grid.
What does 'works required' mean on a DNO application?
It means the DNO has decided their own network equipment needs upgrading before your system can connect. This is different from 'further information required', which is a paperwork request you can answer the same day. Works required is a network problem, there is nothing to correct on your side, and the DNO will come back with a quote and a timescale for the reinforcement.
Can a DNO approve an application but limit what you export?
Yes. An approval can come back with an export limit attached, which is common where the local network is already constrained. The system is allowed to connect at full generating capacity but an export limitation scheme under ENA EREC G100 caps what it can push back to the grid. It is often the difference between a large installation going ahead and being refused outright.
Does Northern Ireland have the same rules?
No. Northern Ireland has its own electricity network managed by NIE Networks and uses different connection processes. While the general principles are similar, you should contact NIE Networks directly or visit nienetworks.co.uk for guidance on connecting generation in Northern Ireland.