Revisiting the wind-farm and fires debate

Research by Jon Yaakov Gorr.

Photos like this are great if you’re trying to drum up opposition to wind farms. But how serious a risk are turbine fires? Image: ACT Rural Fire Service Photography Blog

Wind-farms and fires – a low risk which is easily managed.   

A number of anti-wind campaigners argue that wind farms pose a fire risk. This is because of the risk of lightning strikes, sparks emanating from turbine equipment and the potential for fires being started during construction and management works. For instance, according to the website of the Caithness Windfarm Information group, “Fire is the second most common accident cause in incidents found. Fire can arise from a number of sources – and some turbine types seem more prone to fire than others. A total of 158 fire incidents were found.”

That’s since 1970, a period of 40 years. There are now over 100,000 commercial turbines in operation world-wide.  So that’s 4 per 100,000 per year.  And whilst any fire is a risk, it is generally accepted amongst researchers that human error or unsafe human behaviour is associated with 80-90% of accidents.

Just one fire worldwide has resulted in any death.  One person has died on planet earth as a result of fires involving windfarms.  That was James Thovson, a 26 year old male who died in Chandler in the US state of Minnesota in 2005. According to the Murray County sheriff’s office, the fire resulted from human error during routine maintenance.

As was proven with the tragic death of Mr Thovson, the biggest problem with turbine fires is that, because of the turbine height, the fire brigade can do little but watch it burn itself out when a fire does start.

But let’s look at the magnitude of the risk.  Compare wind farms, with, say, building sites and you’ll find that 29.4 percent of all fatal injuries in 2008/9 in Australia are attributable to the construction industry – that’s 53 fatal construction injuries in 2008/9.  Labour Force Survey (LFS) data indicates the rate of non fatal injuries for 2007/8 to be 1427 per 100,000 workers; that’s a big difference from just 4.

Or compare wind farms with warehouses. Singapore and Victoria have about the same population; in 2006 there were 9 fatalities and 107 injuries at workplaces just involving forklifts.

In Australia there have been four reported fires involving wind farms.  The first occurred at Ten Mile Lagoon in Western Australia in the mid-1990s and the second at Lake Bonney in South Australia in 2006. Neither fire spread beyond the relevant turbine. Further, the fire in Western Australia occurred with technology that is now redundant. Consequently, in almost 20 years of wind farm operation in Australia, there appear to have been two fires, neither of which resulted in a wildfire and the only property damage caused by the fires was to the relevant wind turbines.

The Victorian Country Fire Authority (CFA), in its 2007 publication Emergency Management Guidelines for Wind Farms, notes that the potential for fire from wind turbines is inherently low. The low fire risk is due to a number of factors:
•    Each wind turbine is connected to a control centre which will shut down the turbines if there is a risk of overheating
•    Wind turbines are a passive technology and have few flammable materials
•    Although wind turbines attract lightning, the built-in lightning protection systems safely dissipate the electricity into the ground, and
•    Wind turbines are located in cleared areas, limiting the chance of fires spreading if they do occur.
the fire risk.

So, as the CFA notes, the low incidence of fire is likely to be attributable to a number of factors. Firstly, wind turbines are a relatively passive technology that use few flammable materials. Secondly, although turbines do attract lightning, their design minimises the associated fire risks. Turbine lightning protection systems are now used that extend from the blade to the bottom of the tower and dissipate lightening into the ground. Thirdly, wind turbines are generally placed in open areas, limiting the chance of fires spreading when they do occur. Finally, due to the financial cost associated with wind farm developments, operators generally manage the sites in a manner that minimises the risk to the turbines and surrounding property.

The risk of fire associated with wind farm developments is minuscule. Provided wind farms are constructed and managed in an appropriate manner, fires caused by wind turbines are likely to be very rare and pose little risk to surrounding property.

According to Grant Flynn of Sustainable Energy Australia Pty Ltd,

“The monetary values exposed to a single fire, no matter how unlikely means that fire risk attracts much more attention that it did in the past. Wind turbines manufactured today incorporate the highest quality and safety standards, but the potential for a fire always exists when electronics and flammable oils and hydraulic fluids exist in the same enclosure. The wind towers can, at times, be considered fire hazards, due to escaped sparks and flames. This only happens when turbine bearings wear out, crankcases run out of lubricant, cables are damaged during rotation, there are electrical shorts, or electrical arcing occurs in the transmission and distribution facilities. Sophisticated condition monitoring systems utilised in modern wind turbine generators ensure that these circumstances do not occur. With normal maintenance and servicing practices in place, a wind farm will not impose an increased fire hazard to the host community. Fires due to machine failure in modern turbines are extremely rare. Cases of fire damage to land neighbouring wind farms are practically nonexistent. According to a leading insurer of wind farms with 15 years of experience and over 12,000 insured turbines, 90% of these very infrequent fires are due to older turbine models. They have had only one case of third-party damage, which was limited to a fire on a large haystack.

Let’s look at the most recent fire:  a fire within one of the turbines at the Star Fish Hill Wind farm, in October 2010.  Star Fish Hill Wind Farm is near Cape Jervis in SA. When a turbine caught alight, firefighters could do little but watch the blaze from half a kilometre away as the situation was deemed too dangerous to approach.  Despite the fire, the blades continued to spin. Fire-fighters kept watch for spot fires but were unable to extinguish those close to the turbine.

The only damage was that the wind- tower self destructed, causing $3 million dollars of damage.   That’s because of the bushfire plans required for wind-farm operators.  The Codrington farm, for example, has a fenced enclosure around the turbine, the ground within which is fully covered with crushed rock.   The nacelle on top of the tower contains the electrical generator and includes lubricating and hydraulic oils, and is surrounded by a fully enclosed thick walled steel cylinder.

In the unlikely event that a fire was initiated within the tower, the fire should be contained within the tower itself. A significant failure of the wind turbine has the potential to initiate a fire. There are electrical, thermal, speed and vibration interlocks that shutdown the wind turbine before a failure has the potential to develop .

In the unlikely event that a fire was initiated in the nacelle there is a potential for debris to fall in high wind and initiate a grass fire if blown clear of the crushed rock area.  This has happened in exactly zero of the four fires in Australian wind farms.

Compare this with the substantial property damage, including death, which has occurred from either arson or bushfires caused by imploding haystacks.  According to data from the Australian institute of Criminology, fire services attend around 54,000 (+/- 6000) vegetation fires per year. The Bushfire CRC, which analysed more than 280,000 fires in Australia covering the best available data from 1997-2006 found that 60 percent of fires have a known cause and around half of these are listed as either suspicious or maliciously lit fires.  That’s 16,800 deliberately lit or suspicious fires each year over 10 years, which include the February 2009 fires in Victoria, which killed over 200 people.

If a haystack heats up due to its moisture content to 70 degrees, it may spontaneously combust.  Victoria, with only a quarter or Australia’s population,  averages over 220 haystack fires alone each year.   That’s equivalent to a national tally of 8800 in a ten year period, as against four wind-farm fires.

There’s a risk in all sorts of activities. Windfarms, like any other activity, just need prudent management.

Because of a formatting issue, these footnotes have been stripped out of the text. If you would like a Word version of this document, please email Cam:
Caithness Windfarm Information Forum 2010.

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