UK DNOs and Grid Connection for Church Solar — 2026 Guide

Grid connection is one of the least visible parts of a parish solar project — until it causes a delay. Every solar PV installation requires DNO (Distribution Network Operator) approval before it can export to the grid. For the great majority of parish projects this is a straightforward notification process. For a minority — rural parishes on long single-phase feeders, Scottish and Welsh sites on constrained networks, larger cathedral-scale systems — it becomes a genuine project risk. This guide explains the process, the timescales, what causes delays, and how to plan around them.

What DNOs are

UK electricity distribution is managed by regional monopoly companies called Distribution Network Operators (DNOs). There are 14 licensed DNO areas in Great Britain, operated by six companies:

Company	Regions covered
UK Power Networks	London, East of England, South East England
Electricity North West	Greater Manchester, Lancashire, Cumbria, Cheshire
National Grid Electricity Distribution (formerly WPD)	Midlands, South West England, Wales
Northern Powergrid	Yorkshire, North East England
Scottish and Southern Electricity Networks (SSEN)	North of Scotland, South of England (Hampshire, Berkshire, Oxon, Bucks)
SP Energy Networks	Central and Southern Scotland, Merseyside, North Wales
Northern Ireland Electricity Networks (NIEN)	Northern Ireland (separate regulatory regime)

Every solar installation in Great Britain must notify or apply to the relevant DNO. There is no opt-out. The DNO uses the notification to update its network records, assess whether the proposed generation can be accommodated without voltage or stability issues, and issue a connection agreement.

G98 vs G99 — which applies to your parish

The Energy Networks Association technical standards G98 and G99 determine which application process applies and how much DNO scrutiny your connection receives:

G98 — for smaller systems

G98 covers connection of generating units below 16 A per phase (roughly 3.68 kW single-phase; up to around 13 kW on a single-phase supply; any size on three-phase up to the per-phase limit).

In practice, most DNOs extend G98 treatment to single-phase systems up to approximately 13 kW, and some to 16 kW, subject to network conditions.

G98 application process: Simple notification rather than formal approval. The installer submits a G98 notification form (available on each DNO’s portal) with basic details of the system. The DNO reviews it and either acknowledges it (within the statutory window) or raises objections.

Typical G98 timescales:

• UK Power Networks: 4–6 weeks
• Electricity North West: 5–8 weeks
• National Grid ED: 5–8 weeks
• Northern Powergrid: 6–10 weeks
• SSEN (southern England): 6–10 weeks
• SP Energy Networks: 6–10 weeks
• SSEN (Scottish Highlands): 8–16 weeks (longer for remote areas)

G98 fees: DNO notification fee typically £100–400. No connection fee for G98 if the existing supply cable is adequate.

G99 — for larger systems

G99 applies to all systems above the G98 threshold — typically anything above 13–16 kW on a single-phase supply, or three-phase systems of any size above the per-phase limit. For parish solar, G99 most commonly applies to: systems above 15 kW on single-phase supplies, hall-and-church combined systems above 20 kW, and three-phase installations on larger buildings.

G99 application process: More substantial. Requires a formal application with technical documentation, a DNO technical study (power flow modelling to confirm the proposed generation can be accommodated on the local network without voltage, frequency, or stability issues), and a formal connection agreement.

Typical G99 timescales:

• UK Power Networks: 8–12 weeks
• Electricity North West: 8–14 weeks
• National Grid ED: 10–16 weeks
• Northern Powergrid: 10–18 weeks
• SSEN (southern England): 10–16 weeks
• SP Energy Networks: 10–16 weeks
• SSEN (remote Scotland/Highlands): 16–28+ weeks

G99 fees: Application and study fee typically £400–1,500. Connection fee (for connection to the DNO’s network, if required) typically £500–3,000 for standard parish-scale connections. Network reinforcement charges (where required) can be significantly higher — see below.

What causes delays and how to avoid them

Voltage rise issues

Solar PV pushes voltage up on the local distribution network as it exports electricity. In rural areas with long single-phase feeders, the existing network voltage may already be close to its upper limit. Adding generation can push voltage above G98/G99 permitted limits, requiring either: (a) limiting the system’s export to stay within voltage limits, or (b) network reinforcement to accommodate the generation.

Voltage rise is more common in:

• Rural Wales and south-west England (long rural feeders, many existing renewables)
• Scottish Highlands and Islands (constrained networks, high existing renewable generation)
• Rural English parishes more than 500m from a substation on a single-phase supply

The solutions and their costs:

• Export limitation (DNO preference, cheapest): The inverter is configured to cap export at a level that keeps network voltage within limits. For parish solar, this typically means limiting export to 50% of system capacity or less. This doesn’t reduce generation — it just means surplus is either stored (battery) or curtailed when the battery is full.
• Network reinforcement (expensive, slow): Upgrading the substation transformer, replacing the feeder cable, or adding reactive power compensation. DNO-led reinforcement costs can range from £5,000 to £50,000+ and add 6–18 months to connection timescales. This is rare for standard parish-scale systems but does occur in severely constrained rural networks.

Three-phase upgrade requirements

If the proposed system exceeds the G98 single-phase limit and the parish currently has a single-phase supply, upgrading to three-phase supply may be required. Three-phase upgrade:

• Takes 4–12 weeks (DNO workload dependent)
• Costs £4,000–£12,000 depending on distance to the nearest three-phase point
• Requires a separate application to the DNO

For parish systems intended to exceed 15 kW, we check three-phase availability at the site survey stage. If three-phase is not available and upgrade costs would be prohibitive, this can influence the system size recommendation — sometimes 12–13 kW on single-phase is more practical than 20 kW requiring three-phase upgrade.

DNO study complexity

For systems above 30 kW, or on networks with many existing renewables already connected, the DNO technical study becomes more complex. The DNO must model the interaction of the proposed generation with all other generators and loads on the relevant section of network. This can require:

• Detailed power flow analysis (computerised network modelling)
• Load flow studies under various demand and generation scenarios
• Harmonic distortion assessment (for larger inverter-based systems)

Complex G99 studies add 4–8 weeks to standard timescales. We flag this risk at feasibility stage for cathedral-scale and multi-building systems.

Network reinforcement in constrained areas

Some areas of the UK have reached or are approaching the limit of distributed generation that can be accommodated without network upgrades. Western Wales, the Scottish Highlands and Islands, parts of the south-west peninsula, and some areas of East Anglia are known constrained zones for distributed solar.

In constrained areas, new G99 connections may require the applicant to contribute to network reinforcement costs — essentially paying a share of the DNO’s infrastructure upgrade needed to accommodate the proposed generator. This can add thousands to tens of thousands of pounds to connection cost. We identify constrained-zone risk at desk feasibility stage using DNO constraint maps and historical project data.

Battery storage and DNO requirements

Adding battery storage to a parish solar installation changes the DNO requirements in ways that many installers don’t fully understand:

Export from battery: If the battery system can export stored energy to the grid (rather than just self-consume), this is treated by DNOs as additional generation capacity. A 10 kWh battery with a 5 kW export inverter is treated similarly to 5 kW of additional PV generation for DNO purposes.

G100 (for battery storage): The Energy Networks Association G100 standard governs connection of energy storage. Battery systems above certain thresholds require G100 compliance documentation alongside the G98 or G99 notification. Most modern battery-compatible inverters are G100-compliant by design; verify this with the inverter manufacturer before specifying.

Non-export mode: Many parish solar + battery systems are configured in non-export mode for the battery — the battery only discharges to self-consumption loads, not to the grid. In non-export mode, the battery doesn’t affect the DNO application for the solar, and no additional DNO approval is needed for the battery itself. This is the simplest approach for most parish installations.

Smart Export Guarantee (SEG) metering and DNO

The SEG (Smart Export Guarantee) entitles generators to payment for electricity exported to the grid. Participating in SEG requires:

• A smart meter (not just a standard generation meter)
• SEG registration with a licensed SEG licensee (most major energy suppliers)

The smart meter installation is coordinated with your energy supplier, not the DNO — but the DNO connection approval must be in place before SEG registration can be completed. Plan the sequence: DNO approval → smart meter installation → SEG registration → first SEG payment.

How we manage the DNO process

For every parish project we deliver, we submit the DNO application at contract signing — typically 4–6 months before planned installation. This timing means DNO approval lands in time for install scheduling without being either rushed or excessive.

Our standard DNO application includes:

• Detailed single-line electrical diagram
• Inverter manufacturer datasheets with G98/G99 type-test certificates
• Site location and supply details (MPAN number, existing supply rating, three-phase availability)
• Proposed connection arrangement and metering scheme
• Earth bonding and protection relay details per G98/G99 requirements

A complete, correctly-formatted DNO application dramatically reduces back-and-forth. We have not had a DNO application returned for incomplete documentation in three years of using our current application format.

Timeline planning for parish projects

DNO scenario	Application submission	Typical approval	Timeline risk
G98, England/Wales, no constraints	Month 4	Month 6–8	Low
G99, England/Wales, no constraints	Month 3	Month 6–10	Low-medium
G98/G99, rural constrained area	Month 2	Month 6–10	Medium
G99, three-phase upgrade needed	Month 2	Month 7–12	Medium-high
G99, network reinforcement required	Month 1	Month 8–18+	High

For standard English parish projects (G98, good networks, no constraints), DNO approval is not on the critical path. For Scottish, Welsh, and rural south-west projects, we treat DNO approval as a critical-path item and initiate it immediately after contract signature.

Practical recommendations for PCCs

1. Confirm your DNO early. Your postcode determines your DNO exclusively. The relevant DNO appears on your electricity bill, or search “[postcode] DNO.”

2. Know your existing supply rating. The main fuse in your consumer unit typically shows the supply rating (60A, 80A, 100A single-phase are common parish supplies). This determines whether three-phase upgrade is likely to be needed for your proposed system size.

3. Allow DNO time in your project plan. For standard English parish solar, 8–12 weeks is a safe DNO timeline assumption. For rural, Scottish, or Welsh sites, build 14–20 weeks. Don’t promise commissioning dates before DNO approval is confirmed.

4. Include DNO fees in your budget. G98 notification: £100–400. G99 application and study: £400–1,500. Connection fee (if required): £500–3,000. These are not typically covered by Buildings for Mission grants; include in parish reserves.

5. For constrained-zone parishes: Ask your installer to check the DNO constraint map for your postcode at feasibility stage. If you’re in a constrained zone, understand the network reinforcement risk before committing to a system size.

For a free feasibility that includes a DNO timeline assessment for your parish’s specific location and proposed system size, request our free feasibility report.