Fanning the Flames - Wind Farms Vulnerable to Fires

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18 July 2014 | Updated 01 January 1970

Wind farming is one of the leading industries in the renewable energy sector. However, according to report from Imperial College, London, incidents of wind turbines catching fire are a big problem that is not currently being fully reported.

Researchers from Imperial College London, the University of Edinburgh and SP Technical Research Institute of Sweden, carried out a global assessment of the world’s wind farms, which in total contain an estimated 200,000 turbines. The team found that 10 times more fires are happening than are being reported. Instead of an average of 11.7 fires each year, which is what is reported publicly, the researchers estimate that more than 117 separate fires are breaking out in turbines annually.

By comparison, with other energy industries, fire accidents are much less frequent in wind turbines than other sectors such as oil and gas, which globally has thousands of fire accidents per year. However, fire accidents can have a considerable economic impact on the wind farm industry, say the team.

Each wind turbine costs in excess of £2 million and generates an estimated income of more than £500,000 per year. Any loss or downtime of these valuable assets makes the industry less viable and productive.

The researchers have made a number of recommendations to reduce fire incidents in wind farms.

Dr Guillermo Rein, from the Department of Mechanical Engineering at Imperial College London, explained: “Wind turbines are viable sources of renewable energy that can assist the world to reduce emissions and help wean us off fossil fuels. Worryingly, our report shows that fire may be a bigger problem than what is currently reported. Our research outlines a number of strategies that can be adopted by the industry to make these turbines safer and more fire resistant in the future.”

Close proximity

Wind turbines catch fire because highly flammable materials such as hydraulic oil and plastics are in close proximity to machinery and electrical wires. These can ignite a fire if they overheat or are faulty. Lots of oxygen, in the form of high winds, can quickly fan a fire inside a turbine. Once ignited, the chances of fighting the blaze are slim due to the height of the wind turbine and the remote locations that they are often in.

Since the 1980s, when wind farms were first constructed, the team found that fire has accounted for 10-30% of reported turbine accidents. In 90% of the cases, the fire either leads to substantial downtime, or a total loss of the wind turbine, resulting in economic losses.

The researchers also outline the main causes of fire ignition in wind turbines in the study. They are, in decreasing order of importance, lightning strike, electrical malfunction, mechanical failure, and errors with maintenance.

Hard to assess

Reports of fires in wind farms are increasing, say the researchers. However, the true extent of these fires has been hard to assess because official reports about fires are either incomplete, biased or contain restricted or classified available data.

In an effort to get a clearer picture about the true extent of fires in wind farms, the team carried out an extensive analysis of data from a wide range of sources. This included government reports, data from anti-wind farm lobbyists and information gathered by major newspaper investigations.

The researchers suggest a number of measures that can be put in place to prevent fires from happening. These include ‘passive’ fire protection measures, such as installing comprehensive lightning protection systems.

Other measures include using non-combustible hydraulic and lubricant oils and building heat barriers to protect combustible materials. Manufacturers are also advised to avoid using combustible insulating materials and apply new monitoring systems to constantly check the condition of machinery so that maintenance work can be carried out in a timely way.

The researchers also suggest a number of ‘active’ fire protection measures that can be used to stop a fire before it takes hold or gets out of control. These include smoke alarm systems inside the turbine, so that fire safety authorities can be alerted rapidly. The team also suggests suppression systems that quickly douse the flames in water or foam.

Pictured: Wind farm turbines may be susceptible to fires, according to research just published by Imperial College

Article written by Mike Gannon | Published 18 July 2014

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