Campaigners have raised fresh concerns about noise restrictions at one of the biggest wind farms in the South West.
Work is now under way to create the 120m (390ft) high nine-turbine Den Brook wind farm between North Tawton and Bow, in Devon.
However, they remain concerned at how a particular noise from the turbines – amplitude modulation (AM), where “swishing” sounds turn to a “thumping”, often at night – are measured.
The firm “completely refutes” the claims, which it says were dealt with by a judge last year.
A meeting last week of the Den Brook Community Liaison Group with RES and West Devon Borough Council failed to resolve the row.
Mike Hulme, of the Den Brook Community Liaison Group, said the council had excluded elements of AM noise from monitoring.
He added: “Such unjustified exclusion may well throw out and so unlawfully exclude otherwise genuine and legitimate noise complaints from being properly assessed.
“What’s more, unwarranted rejection of legitimate noise complaints could potentially lead to uncontrolled sleep disturbance with all the attendant liabilities and well documented long-term implications for people’s health.”
Campaigners want the Government to introduce new standards to replace the existing method by which councils assess wind farms – the ETSU-R-97, which was created in 1996.
Mr Hulme says the true effect of amplitude modulation was being mis-calculated by a “massive amount”. In some cases claims of five decibel (db) noise had been detected as high as 15db, he claimed.
RES said the benefits of Den Brook to the local communities are already being seen with almost £2 million invested in the local and regional economy during the construction of the project so far.
It points to the new link road at Whiddon Down and, once operational, a community benefits package worth more than £2.25 million over the scheme’s lifetime.
A Local Electricity Discount Scheme offers local homes, commercial and community properties within 2.3km of the turbines an annual discount of £108 off their electricity bill, every year, for the lifetime of the wind farm.
A spokesman said the issue of noise measurement has been carefully considered by acoustics experts through the lengthy planning and legal processes that led to the approval of the Den Brook project.
“Mr Hulme’s latest concerns relating to noise issues at Den Brook were thoroughly considered by the High Court and were roundly rejected – his case was so weak that he was not granted leave for any further appeals,” the firm added.
“The view of the noise experts associated with this case is clear – that the noise measures being implemented by RES offer the best protection possible for nearby residents should there be any noise impact.
“RES has also made clear its commitment to ensure that any potential instances of noise impacts that may occur are fully investigated.
“Mr Hulme’s suggestion that RES has acted irresponsibly and not in the best interests of the local community is wholly unfounded.”
West Devon Borough Council said it is aware of the concerns.
“Many of the concerns that have been raised were subject to a Judicial Review, where the council was successful in defending its position,” a spokesman added.
“The inspector agreed with the council that a scheme to measure the sound made by passing rotor blades should be put into place.
“We would like to reassure residents that the council will properly investigate any future complaints of disturbance.”