Payback · Northern Ireland · United Kingdom
Commercial solar payback in Downpatrick: 4.9 years
A self-consuming 100 kWp array on a commercial roof in Downpatrick typically pays back in about 4.9 years. That figure uses Downpatrick's specific yield of 930 kWh per kWp per year and a commercial tariff near £0.28/kWh, with 70% of generation used on site.
At that yield the array produces about 93,000 kWh a year and saves roughly £18,228 annually against an installed cost near £90,000. Over 25 years the net saving is around £365,700, while avoiding about 32.5 tonnes of CO₂ each year.
Downpatrick is in Northern Ireland, alongside Belfast, Londonderry and Lisburn. Those towns share the same irradiance zone, so payback is similar — the difference is which warehouses and factories still have empty roof. SolarScout lists them with a pre-computed business case rather than a generic "solar is cheap" pitch.
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Scan this area free →How the Downpatrick payback number is calculated
Start with 100 kWp × 930 kWh/kWp = 93,000 kWh of annual production on a representative warehouse or factory roof in Downpatrick. Apply 70% self-consumption against £0.28 per kWh and you get about £18,228 a year. Divide the £900/kWp installed cost (£90,000 for 100 kWp) by that saving and payback lands at 4.9 years.
This is a worked example, not a quote. Real payback moves with self-consumption, shading, export tariff and installed cost. It is still the right first filter: if a roof in Downpatrick cannot beat roughly 4.9 years on these inputs, it is probably not a priority lead.
Downpatrick versus the rest of United Kingdom
Relative to United Kingdom as a whole, payback in Downpatrick is a little slower than the United Kingdom average of 4.6 years, because Northern Ireland sits on the cooler side of the national irradiance band. The UK pairs modest irradiance with some of Europe’s highest commercial electricity prices, so self-consumption on large warehouse and factory roofs pays back fast despite the cloudier climate.
That is why outreach in Downpatrick should open with the local number — 4.9 years and £18,228 a year on 100 kWp — not a national average that under- or over-sells the roof.
What actually changes payback on a Downpatrick roof
Yield is already baked into the 930 kWh/kWp zone for Northern Ireland. The bigger swings are usable roof area, daytime load (factories and cold stores self-consume more than empty warehouses) and whether the site pays the full £0.28/kWh commercial rate.
SolarScout estimates roof footprint from satellite and map data and, where Google Solar coverage exists, modelled annual output — so you can rank Downpatrick sites by savings instead of guessing from a map pin.
Frequently asked questions
What is the commercial solar payback in Downpatrick?
About 4.9 years for a self-consuming 100 kWp rooftop in Downpatrick. That uses 930 kWh/kWp of local yield and a tariff near £0.28/kWh, saving around £18,228 a year.
How much electricity does 100 kWp produce in Downpatrick?
Around 93,000 kWh a year. Multiply the 930 kWh/kWp specific yield for Northern Ireland by 100 kWp; shading and orientation can move that figure, which is why SolarScout models each roof rather than stopping at the city average.
Is payback in Downpatrick better than nearby towns?
Payback is in the same band as Belfast, Londonderry and Lisburn because they share the Northern Ireland irradiance zone. The practical difference is the stock of large, unshaded commercial roofs — SolarScout lists those in Downpatrick with a pre-computed saving so you can compare sites, not just towns.