South Wales receives 940 to 985 kWh per kWp per year according to PVGIS irradiation data -- materially similar to London and significantly higher than Manchester. Paired with commercial grid electricity at 28 to 32p/kWh in 2025-26, the economic case for rooftop PV is straightforward.
A 100 kWp commercial system installed in South Wales typically generates 95,000 kWh annually, producing a year-one benefit of approximately £23,000 and a simple payback of 3.5 years. With 100% Annual Investment Allowance full-expensing against corporation tax, post-tax payback drops to 2.5 years.
For businesses that cannot or do not wish to deploy capital, a fully-funded Power Purchase Agreement installs the system at zero upfront cost and charges only for the electricity generated, at a fixed unit rate guaranteed below your grid tariff.