Solar Compliance in Wales: G99, Planning & SEG Guide 2026

Solar compliance in Wales sits at the intersection of UK-wide grid connection standards and a Welsh-specific planning and policy framework. The devolution of planning powers to the Senedd (Welsh Parliament) means that installers working in Wales must follow Welsh Government planning policy — not the English NPPF — and use Welsh-specific planning legislation for Permitted Development determinations.

At the same time, the grid connection process (G98/G99), MCS certification, and Smart Export Guarantee are the same as in England and Scotland. This guide covers the full compliance picture for solar PV projects in Wales.

DNOs Serving Wales

Wales is served primarily by NGED, with SP Manweb covering the north-east corner.

For most installers working in Cardiff, Swansea, Newport, Pembrokeshire, Ceredigion, Powys, or the Valleys, NGED is the relevant DNO. For projects in Wrexham or the north-east of Wales near the English border, SP Manweb may apply. Always confirm using the ENA postcode tool before submitting.

NGED in Wales

National Grid Electricity Distribution (formerly Western Power Distribution, rebranded under National Grid ownership in 2023) covers the largest part of Wales. NGED’s Wales network faces similar challenges to its South West England network: rural areas with long distribution feeders, agricultural connections, and localised capacity constraints on lower-voltage lines.

NGED operates a flexible connection scheme in parts of its Welsh network — particularly for commercial and agricultural solar above 30 kW — where installations can obtain faster connection approval in exchange for accepting occasional export curtailment. This arrangement suits farm-scale rooftop solar where full export at all times is not essential.

For residential and small commercial G98 projects across Wales, NGED’s standard process applies. The submission portal is at nationalgrid.co.uk/ed. See the NGED DNO guide for full details.

SP Manweb in North East Wales

SP Manweb is the distribution network for parts of north-east Wales and Merseyside in England. If the installation address falls under SP Manweb’s coverage, G98 notifications and G99 applications go to the SP Energy Networks portal at spenergynetworks.co.uk. SP Manweb has broadly the same processes as SP Distribution in Scotland.

G98 and G99 in Wales

The ENA Engineering Recommendations G98 and G99 apply to Wales in the same way as the rest of Great Britain. The thresholds and processes are identical:

• G98: Up to 16A per phase (3.68 kW single-phase, 11 kW three-phase). Prior notification at least 28 days before energisation.
• G99: Above 16A per phase. Full application with 45-working-day DNO response window. Written acceptance required before energisation.

There are no Wales-specific modifications to G98 or G99. The only Wales-specific element is identifying which DNO the notification goes to (NGED or SP Manweb).

For full documentation requirements and the protection relay setting process, see the G98 vs G99 guide.

Welsh Planning Policy

Planning is a devolved matter in Wales. The Welsh Government sets national planning policy through Future Wales: The National Plan 2040, supported by statutory Technical Advice Notes (TANs). Local planning authorities in Wales must follow Welsh Government policy rather than the English NPPF.

Future Wales: The National Plan 2040

Future Wales is the national development framework for Wales. Published in 2021, it sets the strategic direction for planning decisions across Wales for the next 20 years. Policies relevant to solar include:

• Policy 17 (Renewable and Low Carbon Energy): Requires local planning authorities to support renewable energy proposals, including solar. Proposals should be assessed for their contribution to Wales’s low-carbon transition.
• Policy 18 (Renewable and Low Carbon Energy — Locally Generated Energy): Supports smaller-scale renewable energy developments that serve local communities.

Future Wales creates a policy environment broadly supportive of solar, but local development plans and supplementary planning guidance issued by the 22 Welsh local planning authorities can set additional local requirements.

Technical Advice Note 8 (TAN 8)

TAN 8 is the principal technical guidance for renewable energy planning in Wales. The current TAN 8, revised in 2020, provides guidance on assessing renewable energy development proposals including solar PV. Key points for solar:

• TAN 8 applies to both domestic and commercial solar applications
• It sets out the information required in a planning application for solar (visual impact assessment, glint and glare assessment for commercial projects, grid connection strategy)
• It recognises that solar PV is generally a lower-impact technology than wind, and smaller-scale solar proposals should face a proportionate level of planning scrutiny
• For ground-mounted solar on agricultural land, TAN 8 requires consideration of best and most versatile agricultural land designation

TAN 8 also provides context on Wales’s Strategic Search Areas (SSAs) historically designated for large-scale wind energy — these SSAs (from the original 2005 TAN 8) are less relevant to solar but appear in older planning documents and literature. They are not a constraint on solar development.

Welsh Language Requirements

Planning documentation in Wales may need to be available in Welsh as well as English, particularly for large-scale or publicly controversial projects. Under the Welsh Language (Wales) Measure 2011 and associated standards, public bodies in Wales must operate on a “treat Welsh no less favourably than English” basis. For most solar planning applications, English-language documentation is accepted, but applicants for major infrastructure projects should check with the relevant LPA whether Welsh translations are required.

Permitted Development Rights in Wales

Wales uses the Town and Country Planning (General Permitted Development) Order 1995 (as amended for Wales), commonly referred to as the GPDO (Wales). The relevant provisions for solar PV are in Schedule 2, Part 1 (Development Within the Curtilage of a Dwellinghouse) and Part 6 (Agricultural Buildings and Operations).

The Permitted Development conditions for solar in Wales are broadly similar to England but derive from the Welsh legislation. Key conditions for domestic solar:

• Panels must not protrude more than 200mm from the roof plane or wall surface
• Panels must not be installed on a wall or roof slope that fronts a road
• In Conservation Areas, panels must not be visible from a road
• The installation must not be on a Listed Building (see below)
• Panels must be removed when no longer required

For flat roofs, panels on stands can qualify under PD provided the installation does not protrude more than 1 metre above the roof level and does not exceed the height of the building’s parapet or ridge.

Listed Buildings in Wales

Listed buildings in Wales are graded I, II*, and II, as in England. The national list is maintained by Cadw, the Welsh Government’s historic environment service. Solar installations on or within the curtilage of a listed building require Listed Building Consent from the local planning authority. Cadw is a statutory consultee for Grade I and Grade II* listed building applications.

Wales has approximately 30,000 listed buildings. In areas with a high concentration of listed properties — such as Caernarfon, Conwy, Tenby, and central Cardiff — installers should check the Cadw listed buildings online database before advising customers on planning risk.

Conservation Areas

Wales has over 500 designated Conservation Areas. In Conservation Areas, solar panels that would be visible from a road require planning permission rather than PD rights. This restriction applies even if the panels are on the rear roof slope if that slope is visible from a public road or footpath.

Some Welsh local planning authorities have published Solar in Conservation Areas guidance notes. These set out the approach the LPA will take to assessing solar applications in Conservation Areas — reviewing this guidance before submitting an application in a Conservation Area can significantly reduce the risk of refusal.

Building Regulations in Wales

Since 2012, building regulations in Wales have been devolved. The Welsh Government sets its own Building Regulations under the Building Act 1984 as applied in Wales. The structure is similar to England — both countries share approved documents, though Wales sometimes has different versions.

Part P (Electrical Safety — Dwellings)

Building Regulations Part P applies in Wales in the same way as England. Solar PV installation in a dwelling is notifiable work under Part P. The same two compliance routes apply:

1. Competent Person Scheme: MCS-certified installers registered with NAPIT or ELECSA can self-certify and issue a Building Regulations Compliance Certificate.
2. Local Authority Building Control: The installer or homeowner notifies the local authority building control department. An inspector approves the work.

The competent person scheme route through MCS certification is the standard approach for Welsh solar installations.

Part L (Conservation of Fuel and Power)

Building Regulations Part L (Conservation of Fuel and Power) in Wales was updated alongside the English version, though Wales has its own separate Approved Document L (Wales). The energy performance requirements for new build dwellings in Wales follow a similar SAP-based methodology. Solar PV generation can be credited in the SAP calculation to help new builds meet the Part L Carbon Dioxide Emissions Rate target.

The Welsh Government has set ambitious targets under its Wellbeing of Future Generations (Wales) Act 2015 and the Net Zero Wales Carbon Budget 2 (2021–2025), which will likely drive further tightening of Part L requirements for new dwellings in future reviews.

MCS Certification in Wales

MCS certification requirements are identical across the UK, including Wales. The same installer certification, product certification, and installation certificate process applies. MCS certification is required for:

• Smart Export Guarantee eligibility
• Warm Homes Programme and Nest scheme participation where solar is included
• Building Regulations Part P self-certification through the competent person scheme

There is no separate Welsh equivalent to MCS. All Welsh solar installers operate under the same UK-wide MCS framework.

Smart Export Guarantee in Wales

The Smart Export Guarantee operates in Wales in exactly the same way as England and Scotland. Welsh solar system owners with MCS-certified installations can register with any SEG-licensed electricity supplier. Requirements are the same: MCS certificate, system capacity of 5 MW or less, and a smart or half-hourly export meter.

Export rates vary by supplier. As of early 2026, rates range from approximately 3p/kWh to 15p/kWh. There is no minimum rate set by the government. Welsh consumers can choose any SEG supplier regardless of their electricity supply contract.

Welsh Government Grants and Support

Wales does not have a direct equivalent to Scotland’s Home Energy Scotland grant for owner-occupiers. The main Welsh Government programmes for domestic energy efficiency are:

Warm Homes Programme

The Warm Homes Programme is the Welsh Government’s main programme for improving the energy efficiency of homes in Wales. It operates through two main streams:

• Optimised Retrofit Programme (ORP): Targets owner-occupied and private rented homes with whole-house retrofit approaches, which can include solar PV alongside insulation, heat pumps, and ventilation improvements. The ORP is primarily targeted at fuel-poor households.
• Social Housing stream: Funding for housing associations and local authorities to retrofit their housing stock. Solar PV is increasingly included in social housing retrofit projects in Wales.

Nest Scheme

The Nest scheme provides free energy efficiency improvements and boiler replacement for eligible fuel-poor homeowners in Wales. Solar PV can be included where it is identified as appropriate for the property. Eligibility is based on household income and benefit receipt.

UK-Wide ECO4 Scheme

Welsh owner-occupiers who do not qualify for Warm Homes or Nest can access the UK-wide Energy Company Obligation (ECO4) scheme, administered by Ofgem. ECO4 requires large energy suppliers to fund energy efficiency improvements for eligible low-income and fuel-poor households. Solar PV can be funded under ECO4 where it is identified as a qualifying measure.

Solar in Protected Landscapes

Wales has a higher proportion of its land area designated as National Parks and Areas of Outstanding Natural Beauty than most of England. For solar projects in these areas:

National Parks (Snowdonia / Eryri, Brecon Beacons / Bannau Brycheiniog, Pembrokeshire Coast):

• The National Park Authority acts as the local planning authority within the Park
• Each National Park has its own Local Development Plan and supplementary guidance on renewable energy
• PD rights for roof-mounted solar are restricted in National Parks for visible installations
• Early engagement with the National Park planning officer is strongly recommended

Areas of Outstanding Natural Beauty (including Gower, Clwyd Hills, Cambrian Mountains, Lleyn Peninsula, Anglesey, Wye Valley):

• AONBs in Wales are managed by AONB Management Partnerships
• Planning applications within AONBs are determined by the relevant local planning authority, but AONB status is a material consideration
• Visible solar installations on prominent roof slopes may face objections based on landscape character
• Rear-slope and low-profile installations generally have a better chance of approval

Wales vs England: Key Compliance Differences

Using Solar Design Software for Welsh Projects

The compliance documentation for Welsh solar projects — G98 notification forms, DNO equipment datasheets, MCS commissioning records, and planning support information — follows the same structure as English projects. The key differences are the DNO destination (NGED or SP Manweb) and the planning policy context (Welsh Government policy rather than NPPF).

Solar software that handles UK-wide G98/G99 documentation and can generate accurate yield estimates and shading analysis for Welsh properties simplifies the compliance and sales process. For projects in Protected Landscapes, a detailed shading analysis and accurate annual generation figure can support planning applications by demonstrating the system’s contribution to the property’s energy balance.

See the solar designing feature for how SurgePV supports the full Welsh compliance workflow.

Related Resources

• UK Solar Compliance Overview
• G98 vs G99 Guide
• MCS Certification Guide
• Smart Export Guarantee Guide
• Permitted Development Rights Guide
• NGED DNO Guide
• SP Energy Networks DNO Guide
• Solar Compliance in England
• Solar Compliance in Scotland