A warning about the health effects of noise from wind turbines was removed from a government study following pressure from civil servants.
By Alastair Jamieson
Published: 6:04PM GMT 13 Dec 2009
Consultants recommended lowering night-time noise limits because the sounds made by spinning blades were enough to disrupt sleep patterns.
However, the advice, contained in a draft version of their 2006 report, was removed from the final submission which was eventually used in official guidance for local authorities ruling on planning applications from wind farm developers.
It means that hundreds of turbines at wind farms in Britain built since 2006 have been allowed to continue generating high levels of noise.
Evidence of the changed advice was uncovered after a two-year battle using the Freedom of Information Act by campaigners opposed to a wind turbine development close to their home at in mid-Devon.
One of those campaigners, Mike Hulme, said: “This proves what we have been saying all along, that the noise guidelines should be reviewed. They haven’t changed substantially since 1997, in which time the design of turbines has changed and the number of wind farms has increased.
“Turbines used to be about 50 feet and now they are closer to 400 feet.
"Residents are afraid to complain to their council because the problem is then in the public domain and it becomes impossible to sell their house."
The noise warnings were made in a draft report by Hayes McKenzie Partnership (HMP).
It was commissioned by the Department for Trade and Industry, since replaced by the Department for Energy and Climate Change, following a 2004 article in TheDaily Telegraph that identified wind turbines at a Cornish wind farm as giving rise to health problems associated with low frequency noise emissions.
It said the sound caused by “aerodynamic modulation” – the rhythmic ‘whump whump’ of the blades – was enough to disturb the sleep of nearby residents, creating an "adverse" impact on their health, and recommended the night noise limited be cut from 43 decibels to 38.
However, an anonymous government official then inserted remarks querying the impact of the proposed change. “What will the impact of this be?,” the civil servant wrote. “Are we saying that this is the situation for all wind farms ... I think we need a sense of the scale of this and the impact.”
The final report removed any suggestion of cutting the noise limits or adding any further penalty if turbines generated a beating noise — and recommended local authorities to stick to the 1996 guidelines.
Britain has 253 land-based wind farms generating 3.5 gigawatts, but this is expected to double or even triple by 2020 to help to meet targets for cutting CO2 emissions.
A spokesman for the DECC denied officials had put pressure on the consultants to remove the noise warnings.
He added: "Noise impacts are an aspect which is considered within the planning process before any decision is taken whether or not to grant consent to a project."