Commercial solar leasing vs outright purchase hinges on who owns the UK plant, how long you stay, and if daytime load, roof and connection can support it.
Commercial solar PPAs are priced from capital, yield, daytime load, credit and term, not a UK-wide tariff. Export is priced separately from on-site use.
A solar PPA for UK SMEs is a contract to buy on-site generation from a funder that owns the plant. Weigh daytime load, roof rights and how long you stay.