Wind farms have long been blamed for blighting views and killing birds but now it is claimed they are also a bigger fire hazard than commonly thought.
About one wind turbine fire a month is reported publicly around the world but that is “just the tip of the iceberg”, according to Guillermo Rein of London’s Imperial College, co-author of research estimating that the actual number of blazes could be 10 times higher.
That was a lot fewer than in the oil and gas industries where thousands of fires broke out each year, he said. But it can still amount to large losses at wind farms where turbines typically cost at least €1m each and generate hundreds of thousands of euros in income annually.
“The results surprised us a lot,” Mr Rein said, explaining that he and colleagues found information about the extent of turbine fires was often incomplete or not publicly available.
The researchers decided to investigate after noticing media reports on wind farm fires, including one in Australia that started during a heatwave and another in the UK that disrupted traffic on a nearby road.
The amount of flammable material in a turbine nacelle – the housing on top of a windmill that contains mechanical components such as a gearbox – was more than expected, Mr Rein said.
It included soundproofing insulation and cabling, along with lubricating oils that could create a highly flammable combination at high wind speeds.
RenewableUK, the UK wind farm trade body, said the industry welcomed any studies that improved safety standards but questioned the reliability of the sources in Mr Rein’s research. The trade body suggested that it showed a lack of understanding of standard fire safety measures for any large wind turbine.
“The operational practices and design standards are such that the actual safety risks associated with fire are extremely low,” said Chris Streatfeild, RenewableUK’s head of health and safety.
Safety regulators found last year that the industry took the risks seriously, he said, adding that no member of the public had ever been injured by a UK wind turbine.
Mr Rein’s research showed that lightning strikes were the main reason fires started, followed by electrical failures, mechanical malfunctions and lack of maintenance.
Fires were the second leading cause of wind turbine accidents after blade failure and were often hard to stop because the nacelle was so high and wind farms were frequently in remote locations.
The number of wind farms being built has grown sharply in the past decade as governments have encouraged the use of renewable energy instead of fossil fuel power plants that help to cause climate change.
The amount of wind-generated capacity has more than doubled in the past six years to more than 280,000 megawatts, according to the Global Wind Energy Council. It estimates there were 225,000 wind turbines in about 80 countries at the end of 2012.
Turbines typically cost €1m each for an onshore farm and as much as €5m for the much larger turbines used in offshore wind projects.
Mr Rein said he believed there was a case for the industry to examine better ways of protecting turbines from fire with measures such as improved lightning safeguards, non-combustible lubricants and flame-retardant materials.
He and his colleagues plan to study the fire risk at solar farms and other renewable energy schemes.
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