Payback · Wales · United Kingdom
Commercial solar payback in Swansea: 4.7 years
A self-consuming 100 kWp array on a commercial roof in Swansea typically pays back in about 4.7 years. That figure uses Swansea's specific yield of 980 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 98,000 kWh a year and saves roughly £19,208 annually against an installed cost near £90,000. Over 25 years the net saving is around £390,200, while avoiding about 34.3 tonnes of CO₂ each year.
Swansea is in Wales, alongside Cardiff, Newport and Wrexham. 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 Swansea payback number is calculated
Start with 100 kWp × 980 kWh/kWp = 98,000 kWh of annual production on a representative warehouse or factory roof in Swansea. Apply 70% self-consumption against £0.28 per kWh and you get about £19,208 a year. Divide the £900/kWp installed cost (£90,000 for 100 kWp) by that saving and payback lands at 4.7 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 Swansea cannot beat roughly 4.7 years on these inputs, it is probably not a priority lead.
Swansea versus the rest of United Kingdom
Relative to United Kingdom as a whole, payback in Swansea is a little slower than the United Kingdom average of 4.6 years, because Wales 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 Swansea should open with the local number — 4.7 years and £19,208 a year on 100 kWp — not a national average that under- or over-sells the roof.
What actually changes payback on a Swansea roof
Yield is already baked into the 980 kWh/kWp zone for Wales. 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 Swansea sites by savings instead of guessing from a map pin.
Frequently asked questions
What is the commercial solar payback in Swansea?
About 4.7 years for a self-consuming 100 kWp rooftop in Swansea. That uses 980 kWh/kWp of local yield and a tariff near £0.28/kWh, saving around £19,208 a year.
How much electricity does 100 kWp produce in Swansea?
Around 98,000 kWh a year. Multiply the 980 kWh/kWp specific yield for Wales 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 Swansea better than nearby towns?
Payback is in the same band as Cardiff, Newport and Wrexham because they share the Wales irradiance zone. The practical difference is the stock of large, unshaded commercial roofs — SolarScout lists those in Swansea with a pre-computed saving so you can compare sites, not just towns.