Throughout history, wind energy has been harnessed by humans dating back to around 5,000 BC. The Dutch have been recognized for their innovative use of windmills. However, prior to the current century, wind energy was predominantly utilized on a local scale and was not widely integrated into mainstream utility systems. It was not until the oil crises of the 1970s that significant advancements were made in exploring alternative energy sources. Additionally, in the 1990s and 2000s, the federal government initiated proactive measures to promote renewable energy options, such as wind energy.
There are several factors contributing to the increased utilization of wind energy, with some of the most notable reasons including the following:
1- This fuel source is considered environmentally friendly, producing minimal pollution in contrast to power plants that burn fossil fuels.
2- Wind power is a local energy resource that is typically widely available worldwide.
3- Wind power is considered a sustainable energy source due to its reliance on the continuous presence of wind for energy generation.
The proven efficacy of wind energy as a sustainable energy option is widely acknowledged. However, similar to other beneficial infrastructure projects, its implementation is associated with significant costs. For instance, a standard commercial wind turbine with a power capacity of 2-3 MW may require an initial investment ranging from $2.5 to $4 million, with annual operation and maintenance expenses estimated between $40,000 and $50,000 per turbine.
It is evident that safeguarding these machines, which range in height from 300 to over 600 feet, is essential to prevent damage or destruction. Fire stands as the second most prevalent cause of wind turbine incidents, with fire incidents frequently contributing to property and personnel losses in wind turbine failures. Hence, a knowledgeable and proactive strategy towards fire prevention and suppression is crucial within the realm of the renewable energy sector for all stakeholders.
In what manner does a fire typically manifest in a wind turbine?
Approximately 90% of fires in wind turbines are known to start in the nacelle, which houses essential components such as the gearbox, generator, controller, transformer, low- and high-speed shafts, and brake. Positioned atop the tower, which provides structural support for the turbine and blades, these fires are commonly triggered by:
1- A lightning strike
2- Electrical malfunction / mechanical failure
3- Maintenance activities (which is when personnel are present and would be at risk)
In the event of a wind turbine fire, what are the ensuing consequences?
Roughly 90% of fires in wind turbines lead to substantial damage or complete destruction of the turbine, along with considerable periods of inactivity resulting in economic setbacks. This is primarily due to the common practice of allowing the fire to extinguish on its own. Additionally, the burning debris that falls or is carried by the wind poses a significant risk of spreading the fire to the ground or neighboring properties, thereby increasing the extent of damage and losses.
The potential for loss as outlined can be effectively reduced by implementing suitable fire suppression techniques, which will be further elaborated upon in the subsequent discussion.
What measures can be implemented to proactively mitigate the occurrence of a nacelle or wind turbine fire?
In the context of fire safety for wind turbines, optimal strategies encompass a combination of passive and active fire protection measures, encompassing both prevention and suppression techniques.
Passive fire protection refers to fire protection measures that do not necessitate further intervention once they have been put in place. Several instances of passive fire protection for wind turbines include:
- Choosing noncombustible materials during construction (in this case, specifically, the nacelle)
- Selecting/using non-combustible hydraulic and lubrication oils
- Compartmentalizing the nacelle area
- Installing lightning protection systems
- Installing systems to monitor the conditions of components/equipment.
So, what are the best, most effective systems to use once a fire has been ignited in a wind turbine?
No matter the extent of passive fire protection measures employed, one should never assume that a fire will not occur. Once a fire occurs, immediate measures must be taken, especially before a small, undetected, and remote fire escalates into one that damages or destroys a wind turbine.
In the case of a wind turbine fire (as with many other industrial fires), active fire protection involves:
- Rapid fire detection
- Triggering of fire alarm systems
- Quick-acting fire suppression systems
Aerosol systems according to NFPA-2010, are the predominant and highly efficient fire suppression mechanisms employed in wind turbines. Upon detection of smoke or heat by a linked sensor, the aerosol system is promptly triggered to release the fire extinguishing substance. This rapid response effectively suppresses and often extinguishes the fire, thereby reducing the likelihood of significant property damage and potential casualties.
It is recommended that all wind turbines be outfitted with a sophisticated fire detection and aerosol suppression system. The implementation of this system incurs minimal costs; however, the potential consequences of not having such a system in place during a fire incident could be significantly detrimental.
It is imperative to adopt a proactive strategy for safeguarding wind turbines against fire incidents. The installation of a reliable detection and suppression system, which is unobtrusive and straightforward, is crucial for ensuring the protection of these valuable assets located in remote and confined environments.