Northern Powergrid: Solar G99 Application Guide

Northern Powergrid is the Distribution Network Operator for North East England and Yorkshire — one of the UK’s largest DNO territories by geographic area. With around 3.9 million customers served across a mix of dense urban centres, post-industrial towns, and rural moorland, the network presents a varied set of conditions for solar installers.

For any grid-connected solar installation in this territory, Northern Powergrid is the relevant DNO for G98 notifications and G99 applications. This guide covers the full process: service territory, the connections portal, G98 and G99 procedures, required documentation, export limitation, and the SSEG process for commercial systems.

Service Territory

Northern Powergrid operates two electricity distribution licence areas:

• Northern Electric — covering County Durham, Northumberland, Tyne and Wear, and Teesside
• Yorkshire Electric — covering West Yorkshire, South Yorkshire, East Yorkshire, North Yorkshire, and parts of Humberside

The boundary between Northern Powergrid and the adjacent DNO, Electricity North West, runs broadly along the Pennine range. Installers working near the Lancashire-Yorkshire border, or in areas around Harrogate or the Dales near the North West boundary, should check specific postcodes.

For the rest of northern England, Northern Powergrid is the sole LV and HV distribution operator for generation connections. There is no overlap with National Grid Electricity Distribution (NGED) — NGED’s East Midlands territory starts south of Lincolnshire and Derbyshire, well clear of Northern Powergrid’s southern boundary.

G98 vs G99: Quick Reference

The national thresholds apply in Northern Powergrid’s area as everywhere in Great Britain:

For most residential installations in Yorkshire and the North East — a 3.5–4 kW system on a standard single-phase supply — G98 applies. Any three-phase residential system, larger rooftop commercial installation, or ground-mount system falls into G99 territory.

Full details on the threshold calculation and examples are in the G98 vs G99 guide.

Northern Powergrid Connections Portal

All generation connection applications with Northern Powergrid are handled through the connections section of the Northern Powergrid website at northernpowergrid.com.

The portal supports:

• Generation connection enquiries
• G98 notification submission
• G99 application and document upload
• Application status tracking
• Connection Offer review and acceptance
• Commissioning test result submission

Installers and contractors register a portal account to access generation connection features. Using a single organisational account keeps all project applications in one place and simplifies status tracking across multiple concurrent jobs.

G98 Notification Process

For systems generating at or below 16A per phase:

1. Install and commission the system in accordance with G98 and MCS standards.
2. Within 28 days of commissioning, log in to the Northern Powergrid portal and submit a G98 notification.
3. Enter: site address, inverter make and model, G98 type-test certificate reference number, installed capacity (kW), and MCS certificate number.
4. Northern Powergrid acknowledges the notification. No approval or Offer is issued under G98.

The MCS-certified installer carries the legal obligation to submit the notification. Property owners should not be left to file this themselves.

G99 Application Process

Step 1: Generation Connection Enquiry

Before submitting a full G99 application, run a generation connection enquiry via the Northern Powergrid portal. This step takes approximately five working days and returns:

• An initial capacity assessment at the connection point
• Whether export limitation is likely to be applied
• The appropriate connection voltage (LV or HV)
• Any likely reinforcement requirements

Running the enquiry before the full application prevents surprises at the Offer stage and avoids re-engineering the system design after receiving restrictive conditions.

Step 2: Full G99 Application

Submit the complete G99 application through the portal. Required documents for a standard LV connection:

• Completed G99 application form (available on the portal)
• Single-line diagram showing inverter, protection, isolation, and metering arrangements
• Site layout drawing
• Inverter datasheet with G99 type-test certificate or G99 compliance declaration from the manufacturer
• Earthing arrangement details
• Protection relay settings and associated test certificates (for systems requiring dedicated protection)
• Planning permission reference or confirmation of permitted development rights

For systems above 50 kW, a Protection and Automation (P&A) report is also required. The P&A report must be prepared by a qualified engineer and demonstrate that the protection scheme meets G99 and any Northern Powergrid supplementary requirements.

Using solar design software that produces G99-compliant single-line diagrams directly from the system model cuts application preparation time and reduces the risk of documents being returned for correction.

Step 3: Technical Assessment and Connection Offer

Northern Powergrid assesses the application against network capacity and G99 requirements. The target is 45 working days for standard LV applications. This window may extend for:

• Systems in areas with constrained network capacity
• Applications requiring HV connection
• Projects triggering reinforcement assessments

On completion of the assessment, Northern Powergrid issues a Connection Offer. The Offer states: approved connected capacity, any export limitation conditions, protection and metering specifications, connection costs, and the acceptance deadline.

Review the Offer in detail before accepting. Once accepted via the portal, the Offer terms become contractually binding.

Step 4: Installation and Commissioning

Install the system according to the accepted Offer conditions, Engineering Recommendation G99, and BS 7671 (IET Wiring Regulations). On completion, carry out the G99 commissioning tests. The full test procedure is set out in the G99 commissioning test guide.

Complete the Commissioning Declaration and submit it to Northern Powergrid via the portal, along with the commissioning test results. Northern Powergrid registers the generation unit on their network records, completing the formal connection process.

Export Limitation in Northern Powergrid Areas

Export limitation conditions apply where the local LV network lacks headroom for full export from the proposed system. In Northern Powergrid’s area:

• Urban West Yorkshire (Leeds, Bradford, Huddersfield) — increasing solar density has put pressure on parts of the LV network. Export limiting is applied in specific constrained areas.
• Rural areas — the North East and Yorkshire Dales generally have more network headroom for generation, but individual transformer constraints still occur.
• Industrial areas — Teesside and Humberside have mixed generation and load profiles; connection assessments can yield variable results.

Export limitation types Northern Powergrid may apply:

If zero export is imposed on a system where the customer expects export income, reconsider the design. Adding battery storage to shift generation to behind-the-meter consumption is the most straightforward mitigation.

Northern Powergrid SSEG Process

Small Scale Embedded Generation (SSEG) refers to LV generation systems that connect under G99 but are assessed on a simplified basis compared to large commercial or HV applications — typically systems below 50 kW.

The SSEG route follows the standard G99 application process through the Northern Powergrid portal but without the requirement for a full Protection and Automation study (unless the system’s protection arrangements are non-standard). The documentation requirements and timelines are the same as for any other G99 application.

For systems between 50 kW and 1 MW, the full G99 process applies, including a P&A report and potentially a formal network study. Installers working at this scale should engage Northern Powergrid’s connections team early to understand requirements before committing to a system specification.

Connection Costs

Northern Powergrid’s connection costs are cost-reflective and determined by the technical assessment for each site:

These are indicative. Actual costs are stated in the Connection Offer. Costs typically cover Northern Powergrid’s application assessment, any new metering arrangements, and civils or network works required.

Practical Tips for Yorkshire and North East Installers

A few points specific to this network territory:

• Check the meter operator arrangement early. Northern Powergrid coordinates with network meter operators, but for export metering the property owner will need to engage a Meter Operator (MOP) and a Data Collector (DC/DAF). Clarify this before the customer expects to start earning SEG payments.
• Plan around agricultural schedules for rural sites. Road closure permits and access arrangements in rural North Yorkshire and Northumberland can delay civil works on ground-mount projects. Factor this into project programmes.
• Three-phase supplies are more common in some Yorkshire commercial areas. A three-phase supply does not automatically mean G99 applies — the threshold is per-phase current. A well-balanced three-phase system at 16A per phase each (≈11 kW total) still falls under G98.
• Keep records of G98 notifications. Northern Powergrid, like all DNOs, can inspect records at any time. MCS-certified installers should retain copies of all notification confirmations alongside the commissioning paperwork.

Using Solar Design Software for Northern Powergrid Applications

A complete G99 application to Northern Powergrid requires accurate technical documentation produced directly from the system design. Using solar software that integrates design and compliance documentation — generating single-line diagrams, equipment schedules, and protection settings from the design model — reduces the manual step of producing these documents separately and minimises the risk of inconsistencies between the design and the submitted paperwork.

This is particularly useful when running multiple concurrent projects across Yorkshire or the North East, where managing several G99 applications at different stages simultaneously is common.

Northern Powergrid Contact Information

Related Compliance Resources

• G98 vs G99: Which Applies to Your System?
• G99 Application Guide — Full Process
• G99 Commissioning Test Requirements
• UK Power Networks: G99 Application Guide — London, South East, East England
• NGED: G99 Application Guide — Midlands, South West, Wales
• Electricity North West Guide — Lancashire, Cumbria, Greater Manchester
• UK Solar Compliance Overview
• England Solar Compliance

Frequently Asked Questions

What areas does Northern Powergrid cover?

Northern Powergrid serves North East England and Yorkshire, covering around 3.9 million homes and businesses. The territory includes County Durham, Northumberland, Tyne and Wear, Teesside, and the full Yorkshire region — West Yorkshire, South Yorkshire, East Yorkshire, and North Yorkshire. It is one of two DNOs operating in northern England; Electricity North West covers Lancashire, Cumbria, and Greater Manchester.

How do I submit a G98 notification to Northern Powergrid?

G98 notifications for Northern Powergrid are submitted through the Northern Powergrid connections portal at northernpowergrid.com. Log in with your installer account, select ‘G98 Notification’, and provide the site address, inverter make and model, G98 type-test certificate reference, installed capacity, and MCS certificate number. The notification must be submitted within 28 days of commissioning. Northern Powergrid will send an acknowledgement — no approval is issued.

Does Northern Powergrid apply export limitation to solar systems?

Northern Powergrid applies export limitation where the local network lacks capacity for full export from the proposed system. Yorkshire has seen increasing solar deployment, and some urban areas — particularly in West Yorkshire — have constrained LV capacity. Always run a generation connection enquiry before submitting a full G99 application to identify any likely export limitation conditions.

What is the G99 timeline for Northern Powergrid?

Northern Powergrid targets 45 working days for standard LV G99 applications, in line with the standard across GB DNOs. Systems requiring network reinforcement or HV connection may take longer. Submitting a complete application with all required documents on the first attempt is the most effective way to stay within the 45-working-day window.