The renewables industry has produced a report countering Audit Office findings that single wind turbines in Northern Ireland receive "excessive subsidies".
It complained when the Northern Ireland Audit Office produced its work in 2020.
The auditors found that a turbine could earn £95,000 a year in subsidies, quickly paying back an estimated £300,000 cost and enjoying 16 further years of profit.
At the time Renewables NI said the audit report was "not fit for purpose".
It promised to produce its own figures and commissioned a firm of accountants to do the work.
The Renewables NI report accepts the £95,000-a-year subsidy potential of an individual turbine.
But it found the cost of buying and installing one is considerably higher - at about £570,000 - than reported by the Audit Office.
As such it said the payback period would be longer than suggested and the return on investment within the scheme rules.
The Audit Office suggested that return could be 20% or higher but Renewables NI said it was more like 10%.
In a statement, the Northern Ireland Audit Office said its report had been based on limited information about the cost of turbines.
"It is very difficult to estimate the precise rate of return on an average turbine because much of the information required to do so is commercially sensitive and therefore not publicly available," it added.
It welcomed the Renewables NI report and said it would help the Stormont economy department with a detailed review to ensure subsidy levels were appropriate.
Wind turbines are supported under a 20-year subsidy scheme which is now closed to new entrants.
The cost of paying subsidies for renewable power generation is shared across all UK bill payers, but Northern Ireland contributes less due to the high cost of electricity and levels of fuel poverty.
The cost to bill-payers in Northern Ireland is about £31 a year, about a third of what it costs customers in Great Britain.