| Written by Michal Wozniakowski-Zehenter
In this post, you will find information and an overview of what risks are present in different stages of windfarm operations – from construction to maintenance and decommissioning. It will give you more insights into which areas to focus on while considering the safety aspect.
If it helps to prevent even the smallest incident, it is worth reading it and implementing it in your daily operations in the offshore wind farm. Interested? Then, let’s go.
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For years the global goal has been to reduce the usage of fossil fuels in favour of renewable energy, whether it’s solar energy, water plants, or windmills. Offshore wind parks are one of the most crucial and most hostile environments, yet extremely sufficient to produce energy. Right now, there are nearly 200 offshore windfarms located in different parts of the world, with China, the UK, Taiwan, Denmark, and the Netherlands as global leaders in this field, with Hornsea 2, located almost 90km off the Yorkshire Coast, comprised of 165 wind turbines and providing power to 1.4 million UK Households. It takes approximately 25-35 years for the life cycle of a turbine to come to an end due to atmospheric conditions, huge pressure put on the materials, and the results of the saltness of the water.
From construction through operation, and maintenance to decommissioning, scrutiny of planning and execution undergoes crucial health and safety risk assessment. In addition, workers and equipment are regularly brought to those remote turbines for installation or service.
So, what are the biggest concerns of keeping men safe during different periods of the turbine’s lifetime?
During this phase, usually, a large number of personnel is on-site, carrying multiple separate operations. It’s a lot of vessel manoeuvring and assembly of the assets simultaneously done in different areas. Heavy and bulky objects are lifted from the vessel to the structure of the turbine with common load sharing, which is often seen in those situations when components are being installed on a turbine, but still being held by the crane on the vessel.
Weather forecast is something operating supervisors are paying close attention to, with the most common wind with strong gusts, tides, currents, and waves. Some of the operations might be done only during certain weather conditions, which might lead to additional pressure on the crew to manage all the tasks within a minimal timeframe.
Also, in the build-up phase, some subsea operations are executed, leading to scrupulous and detailed planning of all movements and execution.
Even though the number of risk scenarios is smaller than in the previous phase, there are still many situations where things might not go as planned. Here, we have a very reduced number of personnel working on each turbine, leading to remote and lone operations. In case of an emergency, bringing a rescue team to the turbine will cost valuable minutes, which can be crucial in life-threatening situations.
In addition, lifting long trailing cables may cause getting caught and entangled around different components and ladders, causing dangerous problems, including damaging the vessel or parts of the tower structure or a nacelle. Again, planning is crucial, considering cargo, transportation, weather, and human resources. Not having the adequate size ship to transport the equipment or spare parts, having shortages in personnel, or rough weather conditions will put unnecessary risk on the operation.
Reality shows that for years, the transport chain for lifting heavy components, which should be planned to the smallest detail, is usually interrupted already in the first stage of delivering goods to the turbine. Inaccurate estimations of crane length, spacial deficiency, and poorly balanced cargo with no suitable anchor points are forcing technicians to improvise and bend the rules to find a solution under the pressure of a ticking clock.
Luckily, the situation has improved over time with the realization that better planning can significantly increase the level of safety as well as productivity.
In case of an incident, you should plan ahead for emergency mustering and rescue from the walk-to-work vessel or the wind turbine itself.
It’s the process that starts together with building the turbine. It includes planning, disassembling, transportation, waste management, and post-decommissioning of turbines and other supporting structures. The goal is to return the site to its original condition. Again, as with the construction phase, we will have a large number of engineers, sub-contractors, technicians, boat operators, and divers. Making sure all of them can perform their duties in a safe environment is one of the priorities.
Disconnecting turbines and all cabling from the substation and removing all hydraulic fluids and other toxic substances from the nacelle is just the beginning. Falls from significant heights are the associated risk with those activities. Some parts might be already torn down and used, or just old, which can lead to flooding of some areas or compartments, which can lead to stability issues – quantity and the weight of the water might be unknown to estimate damages and influence on the structure. After unbolting and cutting the structure comes lifting and loading onto the transportation vessels. The number of ships differs depending on lift configuration.
Barges, floating cranes, barges, and heavy lift vessels are usually involved in the operation. What can go wrong here? Plenty of things, starting with movements of other watercraft, positioned close to each other as well as to the turbine. Exceeding the Safe Working Load capacities of cranes, faulty integrity of lifting points, and lack of the proper fastening of the cargo might lead to movements of components causing falls and influencing vessel stability and ballasting.
Suppose the planning of the number of vessels was inaccurate or the arrangement of the layout of cargo. In that case, the capacity of deck loading might be exceeded, which can harm workers and equipment by falling over. Lack of proper tools and wrong maintenance might lead to delays in disassembly, which taking into consideration the harsh weather condition, might lead to extreme fatigue and human mistakes, slips, and falls as injuries.
Windfarm maintenance workers are exposed to hazardous conditions and big heights. Most common injuries include falls, burns from electrical shocks and fires, and crushing by heavy equipment parts.
Wind turbines require systematic maintenance two to three times a year. This number might increase with the ageing of the equipment. It includes turbine inspections and cleaning, lubrication of the moving parts, and repairs.
Offshore windfarms are a key component of the renewable energy solution, and with rising demand to become less dependent on oil and coal, green solutions are preferable. In recent years the industry has made huge steps in overcoming challenges. With the experience comes optimization of the process. Design and structural integrity of turbines, new technologies and materials, transportation and installation of large-size components are picked up to a higher quality level. That also involves safety issues which are being improved constantly.
Using new technologies such as aerodynamic braking systems for the blades, fire detection and protection systems, life vests, and crew and vessel tag locators and readers are all helping to maintain a safer working environment for all involved parties. As we know, all phases of operations bring risks, but proper planning, monitoring, and evaluation of conditions together with good coordination and execution can and will bring results in safety and also improve the efficiency of your offshore windfarm maintenance operations.
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