What is different about commercial solar PV in Northern Ireland?
Five rules differ from Great Britain: who connects the system, which application route applies, whether a roof needs planning permission, how generating plant is treated for business rates, and how exported power is paid for. Once they are settled, a project follows the stages on the commercial PV installations page.
| Topic | What applies in Northern Ireland | Source |
|---|---|---|
| Network operator | NIE Networks owns and operates distribution for over 966,000 customers | NIE Networks |
| Connection route | G98/NI, G99/NI Fast Track or G99/NI, chosen by size | NIE Networks |
| Planning | Part 37 of the Planning (General Permitted Development) Order (Northern Ireland) 2015 | legislation.gov.uk |
| Business rates | Generating plant of 50 kW or less is not rateable | Department of Finance |
| Export payment | The Great Britain export scheme (SEG) is open only to installations in Great Britain | Ofgem |
Behind all five sits the Single Electricity Market, the wholesale market for Ireland and Northern Ireland. Its operator is a joint venture of EirGrid and SONI, which runs the Northern Ireland transmission system.
Who connects a commercial solar system to the grid in Northern Ireland?
NIE Networks. The Energy Networks Association lists it as the only operator for Northern Ireland, so there is no regional split to work out first. The guide to network capacity and heat maps explains how Great Britain operators publish capacity; NIE Networks has its own map.
NIE Networks sorts generation into three routes. G98/NI covers up to 16 A per phase, which is 3.68 kVA on a single phase or 11.04 kW on three phases. G99/NI Fast Track covers up to 60 A per phase, with each inverter limited to 32 A per phase and export to 16 A per phase; that limit rose from 16 A on 1 May 2026. Anything larger needs a full G99/NI application.
G99/NI is not fit-and-inform, because approval must be granted before installation begins. NIE Networks manages capacity with a queue, and a place in it depends on when an application is valid and the fee is received. Where an application seeks export under permitted development, evidence of planning permission is due within 120 calendar days of the connection offer, or the export capacity can be retracted.
The capacity map shows availability at primary-substation level, with a generation mode. Its data were last updated on 26 June 2026, and NIE Networks says it cannot be relied upon for the terms of connection for specific premises. Capacity can be tight: generation export applications at the Limavady Main substation were accepted only from 15 September 2026, after upgrade works.
Does a commercial solar roof in Northern Ireland need planning permission?
Often not, if the system is small and within the limits. Part 37 of the 2015 Order covers installing solar PV on a building other than a dwellinghouse or block of flats, but not where equipment would protrude more than 20 centimetres beyond a roof slope visible from a road, rise more than 2 metres above a flat roof, or sit within 2 metres of a flat roof edge. It also excludes road-facing walls and roof slopes in conservation areas and World Heritage Sites, and the curtilage of a listed building without listed building consent.
Part 37 is headed non-domestic microgeneration, and the Order sets microgeneration at no more than 50 kilowatts of electricity. A larger array is worth raising with the council before it is assumed to be permitted development.
Ground-mounted systems fall under Class B, which excludes stand-alone solar over 2 metres high, within 5 metres of the curtilage boundary or larger than 30 square metres. That is small against a warehouse yard or car park canopy, so those systems are likely to need an application. The English rules in the planning guide do not carry across.
How do business rates treat commercial solar in Northern Ireland?
Land & Property Services values properties subject to rates, and the current valuation list became operative on 1 April 2023. Under the Rates (Microgeneration) Order (Northern Ireland) 2012, generating plant of 50 kW or less is not rateable. Above that, the Department of Finance practice note values plant that serves mainly self-consumption with the building. The Great Britain position is covered in business rates and rooftop solar.
Can a Northern Ireland business use the Great Britain export scheme?
No. Ofgem says SEG installations must be located in Great Britain, so Great Britain tariff comparisons do not carry across and export terms need confirming with a supplier serving Northern Ireland. The SEG guide for businesses explains the Great Britain scheme.
How much does a commercial array generate in Belfast and Derry~Londonderry?
| Location | South, 35° (kWh per kWp) | South, 10° (kWh per kWp) | East-west, 10° (kWh per kWp) |
|---|---|---|---|
| Belfast | 919 | 828 | 756 |
| Derry~Londonderry | 841 | 769 | 709 |
Values are annual kWh for 1 kWp from PVGIS 5.3 (PVGIS-SARAH3 data, 14% losses, calculated terrain horizon) at approximate city-centre coordinates. East-west averages an east-facing and a west-facing plane. Derry~Londonderry is about 8% below Belfast on the south 35° layout, so check a proposal's yield against the nearest row. The yield by region guide compares 13 locations.
Which Northern Ireland businesses make the strongest cases?
NISRA counted 82,680 VAT and/or PAYE registered businesses in March 2026. Of these, 89.4% were micro-businesses with fewer than 10 employees. Belfast had the most (12,100, or 14.6%), and Production businesses numbered 5,615. That suggests many small premises and fewer large industrial roofs, which the manufacturing and warehouse sector pages cover.
Belfast Harbour describes businesses in IT, engineering and aerospace manufacturing, among others, employing more than 20,000 people. Belfast City Council's Local Area Energy Plan names rooftop solar PV and solar carports among five priority projects under a net zero by 2050 target, and the Derry and Strabane climate commission works towards net-zero by 2045.
The Climate Change Act (Northern Ireland) 2022 requires net emissions at least 100% lower than baseline in 2050 and at least 80% of electricity from renewable sources by 2030. In the year to June 2026, renewables supplied 4,431 GWh, 50% of gross final electricity consumption, and solar was 6% of renewable generation.
What about sites on both sides of the Irish Sea?
Each site needs its own check. Pages for Scotland, the North West and Liverpool cover Great Britain, and a reader can send an enquiry through the site's form.
Sources and checks
All sources were checked on 23 October 2026.
- NIE Networks: home page, connect generation, G99/NI, capacity map
- Energy Networks Association, SONI, SEMO, Utility Regulator
- legislation.gov.uk: Planning Order Part 37, article 2, Climate Change Act section 1, section 15
- Department of Finance: rates practice note, valuation
- Ofgem SEG page
- NISRA: business register 2026, Census 2021
- Department for the Economy June 2026 report, Belfast Harbour
- Belfast City Council, Derry and Strabane
- PVGIS: Belfast, Derry~Londonderry
Commercial solar PV questions in Northern Ireland
Does a Northern Ireland business apply for G99 as in England?
Not under that name. NIE Networks uses G98/NI, G99/NI Fast Track and G99/NI. A G99/NI application needs approval before installation begins.
Can a ground-mounted array in a factory yard use permitted development?
Only a small one. Class B of Part 37 excludes stand-alone solar over 2 metres high, within 5 metres of the curtilage boundary or larger than 30 square metres.
Does solar over 50 kW add to a rates bill in Northern Ireland?
Plant of 50 kW or less is not rateable. Above that, plant serving mainly self-consumption is valued with the building, so the valuation should be checked with Land & Property Services.
Is the Great Britain export payment available in Belfast?
No. Ofgem says SEG installations must be located in Great Britain, so export terms for a Northern Ireland site need agreeing with a supplier that serves it.