Biuld costs interest payments etc are allowable on any investment of this nature.
And the revenue does not come from the government.
fITs and export are paid by the energy companies
I get that and I doubt the payments could ever change as you have contracts right ?
My point is your income can be clawed back by any government minded to do so in tax if they felt it would be a popular move with voters, recent dissatisfaction about how green energy is subsidised etc and affecting domestic consumers and turning large commercial users away from the uk makes me think that is not unrealistic to think the goal posts might just get moved on you within the next 20 years