Taxation of Feed-in Tariffs and Wind Turbines

I have a client who is installing a wind turbine on their land costing £95,000. It is to generate energy for domestic use and business use - she runs a B & B from home. (She also lets some land.) She says that she is looking to produce approximately £25,000 FITs payments each year which will be well in excess of the domestic/B & B use. Will the excess be subject to income tax? If so, can capital allowances/AIA be claimed on the actual turbine itself? From what I understand so far, if the FITS are tax free, then no Capital Allowances can be claimed; so I would assume that if the excess FITS are taxed, then capital allowances can be claimed proportionately? Also, would any maintenance costs be allowable expenses against the B & B income?

HMRC website about as useful as a chocolate fireguard!

Thanks for your help.

Regards

Jo