For the past three years, wind power has been the second largest source of new electrical capacity in the nation, second only to natural gas. Currently the U.S. has the world’s largest wind power market, generating an estimated 48 billion kWh of electricity in 2008, enough to serve the equivalent of 4.5 million average U.S. households. In addition, wind energy is one of the fastest growing industries in the world.
To produce this level of electricity and to continually increase capacity, new wind turbines must come online and existing turbines must be meticulously maintained. These turbines are increasing in size year after year, with most towers now reaching 50 to 90 meters in height. Adding in the rotor diameter increases the height tremendously; for example, a 90-meter turbine tower would have a total height from the tower base to the top of the rotor of approximately 135 meters.
Working at these heights creates a high-risk environment for employees involved in the construction and maintenance of turbines. Construction crews called upon to perform work at extreme heights need to be aware of the fall hazards and be provided with the best instruction available, not to mention the most advanced fall protection equipment.
Danger on ladders and service lifts
When constructing wind turbines, there are several danger areas where the worker is at risk of a fall. These include working from ladders to erect sections of the tower and working from service lifts to install cabling. Some tower sections have a vertical fall-arrest system in place that can be utilized for fall protection during this step, but some do not. In a ladder or lift situation, a full-body harness and either a sleeve/shuttle for the ladder safety system or a lanyard connected to an anchor within the lift is required.
After the tower has been erected, work on the nacelle â€” the structure that houses all of the generating components, such as the gearbox â€” begins. This includes the installation of electrical control units that require cabling to be installed throughout the length of the tower. Whether working from a ladder or service lift, the worker must wear a minimum of a full-body harness and lanyard connected to an anchor, protecting him or her from a fall of 90 meters or more.
Depending on the environment and project pace, workers may be required to work in fall-arrest equipment all day. If this is the case, be sure to provide comfortable and lightweight equipment that is durable and not binding.
Equipment with multiple anchor points and the ability to house tools will allow the worker to utilize the fall protection equipment for multiple tasks. For work in difficult-to-access areas, added comfort and safety features can be provided in the form of accessories such as a hydration pack or safety straps to prevent suspension trauma in the event of a fall.
Not for the faint of heart
Wind turbine maintenance involves work in one of the riskiest locales in any industry. Maintaining the tower involves the use of the installed ladder in the individual sections of the tower, or the installed service lift to allow access to electrical conduits and structural sections. As in the construction of the tower, a full-body harness and either a sleeve/shuttle for the ladder safety system or a lanyard connected to an anchor within the lift are required.
Accessing the blades and the hub of the blades from the outside of the nacelle is necessary in order to maintain and repair the control mechanisms of the blades and the blades themselves. This can be an extremely dangerous task, so specialty permanent anchorages are required in addition to the full-body harness and lanyard. Cleaning the blades also involves specialty access equipment and rope-access techniques to protect the worker from falls.
Self-rescue equipment and evacuation plans
Working in such high and confined areas is cause for extra preparation in the event of a fall. If a fall occurs in the upper reaches of the tower, rescue can be almost impossible from the ground by conventional methods, so self-rescue and easy-to-use emergency evacuation equipment is a necessity. In preparing to send workers up to construct or maintain the turbine, this equipment will be needed at all points throughout the tower as well as the nacelle.
A plan also needs to be in place in the event of a fire or complete mechanical failure. In each case, speed is essential to a safe evacuation, so rapid descent must be possible for multiple users.
Currently, wind energy is a thriving industry with 116,000 jobs and $19 billion in investment with hopes to one day become the source of 20 percent of the electricity in the U.S., according to the American Wind Energy Association. For workers involved in maintaining the wind towers currently in operation or constructing new ones, fall protection equipment, as well as rescue and evacuation equipment, is a necessity to protect those fearless enough to work at extreme heights from what could be a fatal fall.