The report is based on an "analysis" by anti-wind farm group the Campaign to Limit Onshore Wind Development (Clowd).
It claims that according to statistics released by energy regulator Ofgem, many wind farms are operating at less than 20% of full capacity.
In response RenewableUK said UK wind farms were performing "fantastically well" says in response to the accusations.
The Sunday Times piece ignored the variability of wind energy and singled out a handful of the UK's oldest projects for criticism-out of some 240 operating wind farms.
Ofgem has distanced itself from Clowd's analysis. "Those are not our figures, or our input or our policy," a spokeswoman said.
Nick Medic, head of communications for RenewableUK points out that with the UK's high wind resource, in 2008 onshore wind achieved an average load factor of 29.4%, with 34.9% for offshore wind.
This compares favourably with 49.4% for non-variable nuclear and 35.4% for hydro. "It's very clear that in terms of load factors, the wind industry in the UK is doing better than anywhere else in Europe."
For more see the upcoming April edition of Windpower Monthly