Bill Dodwell, head of tax policy at the accountants Deloitte, told the BBC that he suspected the figure was a "sensible number taking account of the scale of the business and their history of past losses".
Andrew Dodwell, who is trying to stop commercial wind farms being built in Devon, said Good Energy's discount incentive "sounded like bribery" and the prospect of cheaper electricity would not persuade him to stop campaigning against wind farms.