Wind power and other renewables will become the become the world’s second-largest source of power generation by 2015 and close in on coal as the primary source by 2035, according to the International Energy Agency (IEA).

“A steady increase in hydropower and the rapid expansion of wind and solar power has cemented the position of renewables as an indispensable part of the global energy mix,” the IEA said Monday in its annual World Energy Outlook report.

“The rapid increase in renewable energy is underpinned by falling technology costs, rising fossil-fuel prices and carbon pricing, but mainly by continued subsidies: from $88 billion globally in 2011, they rise to nearly $240 billion in 2035,” the report added.

Wind turbine noise has hit the headlines recently, but the issues aren’t as clear-cut as some media say. We spoke to Dr. Jeremy Bass, Senior Technical Manager at RES, to uncover a few technical details…

How would you describe the noise a wind turbine makes?

It depends on where you stand and listen!

A typical modern wind turbine, at source, produces noise which is dominated by broadband aerodynamic noise from the blades, and this typically has a noise emission spectrum similar to a ‘hushing’ sound.

A new study has hit the headlines claiming that “wind turbines can ruin a good night’s sleep,” as the UK’s Daily Mail put it. It is apparently the first study to clearly link wind farms to sleep problems for those living in proximity.

Scratch a little deeper and you might find that the study – based on a questionnaire given to two sets of adults in Maine, USA, one living near a wind farm and one not – is not quite as conclusive as it first might seem.

First, the sample size is small, “twenty-three and 15 adults at the Mars Hill and Vinalhaven sites respectively, completed the questionnaires. Recruitment of participants into the far group continued until there were similar numbers as in the near group, 25 and 16 for Mars Hill and Vinalhaven, respectively,” the study itself says. Secondly, “it was clear to the respondents that the questionnaire was directed at investigating adverse health effects potentially associated with IWT [Industrial Wind Turbines] and no distractor questions were included,” again quoted directly from the study.

A recent announcement by Bloomberg New Energy Finance (BNEF) that says the costs of onshore wind farm operations and maintenance (O&M) continue to fall rapidly is further proof that the electricity-generating technology is both affordable and dependable.

The wind energy sector is making significant improvements not just in the capital cost and performance of its turbines, but also in the ongoing cost of operating and maintaining them once installed, the BNEF announcement said, adding the average operations and maintenance costs since 2008 saw a cumulative decrease of 38%, or just over 11% per year.  Operation and maintenance costs are only a small part of the overall costs in particular for onshore wind energy.

“Wind power has done much to improve its competitiveness against gas-fired and coal-fired generation in recent years, via lower-cost, more technically advanced turbines, and more sophisticated siting and management of wind farms,” Michael Liebreich, chief executive of Bloomberg New Energy Finance, said in a press release.

EU Energy Minister John Hayes

It’s been a tumultuous week for the wind power sector in the UK with reports and developments underscoring the industry’s benefits while a furor was breaking out over whether Energy Minister John Hayes had overstepped his position on the popular renewable technology.

By Thursday, Green Party MP Caroline Lucas was wondering publicly if Hayes’s mis-directed anti-wind farm views allow the new Conservative energy minister to even have a future in Britain’s energy department.

Lucas, in a Guardian story, said Hayes’s comments “represent the latest intervention in a co-ordinated campaign by an anti-renewables lobby with vested interests in propping up the declining fossil fuel industries. They peddle a number of myths – on effectiveness, cost and public opinion – which must be challenged.”