Wind Farms as One of The Most Common Sources of Renewable Energy

Abstract

The need for energy from sources with less environmental effect has brought the scientists' attention and greater investment interest in the wind farms sector; which is a solution for the generation of electricity based on the power of the wind but these sectors consider to be new and bring occupational risks. This paper will present a brief historical review of the development and growth of the wind farm sector and evaluation of the occupational hazards and risks, safety that workers in wind farms could be exposed to during installation, operation, and maintenance, which focus mostly on the health-related hazards, safety hazards for the wind farm workers beside of the control measures for those risks and possible corrective-preventive actions for improvement are also provided but this sector still lacks adequate information since the existing fleet of wind turbines is fairly new. Therefore, it is vital to conduct studies on the impact of these work activities on the career and long-term health of all workers entering the sector of wind farms.

Introduction

Wind energy is one of the common renewable energy which has a lower environmental impact. However, windmills have been used for 3000 years at least, for different purposes such as grain or pumping water; The use of windmills (or wind turbines) to generate electricity started in the late nineteenth century with the 12 kW direct current windmill generator built by Charles Brush in the USA and the research carried out by Poul la Cour in Denmark; Although, there was little interest in using wind energy for electricity generation one remarkable development was the 1250 kW Smith-Putnam wind turbine built in the USA in 1941which had a steel rotor 53 m in diameter, full-span pitch control, and flapping blades to reduce loads(Wind energy handbook, 2011).

The history of early wind turbine development started with Golding(1955), Shepherd, and Divine in Spera (1994), they record the 100 kW 30 m diameter Balaclava wind turbine in 1931 and the Andrea Enfield 100 kW 24 m diameter pneumatic design built in the UK in the early 1950s; In this turbine, hollow blades, open at the tip, were used to draw air up through the tower where another turbine drove the generator; In Denmark, the 200 kW 24 m diameter Gedser machine was constructed in 1956, while Electricite de France established a 1.1 MW 35 m diameter turbine in 1963. In Germany, Professor Ulrich Hutter created several innovative, lightweight turbines in the 1950s and 1960s; In spite of these technological advances in the electrical research association in the UK, among others, there was little concern in wind generation until the price of oil climbed significantly in 1973(Wind energy handbook, 2011). And energy independence encourages after the global growth of wind capacity(Yue et al., 2001).

Besides the costs is cheaper than other renewable energies, for example, solar power(IEA, 2019). Moreover, wind power generation is usually regionally decentralized and therefore has the potential to promote economic development in various local areas. As a result, many industrialized and developing countries actively support renewable energy through legislative and policy initiatives (including China, the United States, European Union countries, and many developing countries)(May & Nilsen, 2015). Despite the benefits for the generation of electricity from the wind, adverse health effect has been linked to wind farm workers. Wind turbines generate noise that can be classified into a mechanical noise which is produced from the rotor or gearbox and an aerodynamic noise which is generated by turbulent wind flow near the wind turbine blades; the adverse health effects of wind turbine noise can produce physiological effects, for example, anxiety, tinnitus or hearing loss(Abbasi et al., 2015). World health organizations linked noise annoyance with harmful effects on health-related quality of life(Berglund et al., 1999). This paper will examine the main health-related hazards and risks besides safety hazards and risks which are discrete for wind farmworkers.

Anticipation/Recognition

General hazards and risks: There are many issues have been related to the wind farm. The greatest frequent types of potential wind turbine hazards are related to sound/noise, low-frequency sound, infrasound, dust, shadow flicker, Risks: electromagnetic fields, severe weather; ice fall/ thrown .occupational risk assessment (OSRA) methods are commonly used in order to uncover causes and features of accidents and workplace circumstances in different sectors, In order to produce a safe and healthy work environment that guarantees sustainability in wind turbines, determination of existing and external hazard sources and management of the risks occurred gain great importance(Gul et al., 2018).

Installation issue

Installation in the wind turbine building is a very complex and perhaps a highly dangerous step. Because it covers the basic components, including the foundation and transition piece and the building of the wind turbine contains the majority of the heavy lifting of turbine components with the completion of various tasks in quick sequence, and this represents many issues; It is depending on the size of the wind farm despite the number of workers involved in the installation phase; So, it is essential to consider the installation activities take place in windy areas and that turbine tops are designed to position the blades where the wind blows most strongly; The safety implications of working need to be carefully considered throughout the installation phase as a consequence to exposure to high wind conditions and height; workers can be exposed to fall risk(Webster et al., 2013). Exposure to high winds may possibly make work at high elevations even more harmful. During installation, workers may need to access individual turbine sections to weld or fit individual sections together, run electrical or other lines, and install or test equipment often at heights greater than 30.5 m(Webster et al., 2013). For example, one of the construction workers 19-year-old was killed after falling 30 m down the shaft of a wind turbine; he was working on the inside of the turbine while they were under installation(BBC, 2007). So workers on wind farms should be protected from falls by guardrail systems, safety net systems, and personal fall arrest systems(Webster et al., 2013).

And one of the most common hazards in this sector is noise which can be defined as unwanted sound. Wind turbines generate noise that can be mechanical noise which is produced from the motor or gearbox but if performing correctly, this type of noise from modern wind turbines should not be an issue another noise that can produce is aerodynamic noise which is coming from the wind passing over the blade of the wind turbine, moreover, wind turbine produces a general audible range of sound emissions, that includes a range of Special audible Characteristics (SACs) such as low-frequency noise and tonality, impulsivity, amplitude modulation(Health & Council, 2010). Noise can affect human health and cause hearing loss. (Rogers et al., 2006). Most claims regarding potential adverse noise impacts of wind turbines are concerned with low-frequency noise and infrasound; however, according to (Leventhall, 2006)there is normally little low-frequency noise because there is insignificant infrasound generated by wind turbines. Besides there is a survey of all known published results of infrasound from wind turbines found the new design of wind turbine, where rotor blades are in front of the tower, make a low level of infrasound. But (NRC, 2007)notes that low-frequency infrasound (less than 20Hz) could affect humans health but it is adverse not well understood yet.

Operation issue

The number of workers in the operational phase is lower than in the installation phase. For example, over 500 persons working on-site, but an average operational crew contains two people for every 20 or 30 wind turbines and smaller wind farms they may rely on a regular visit from regional teams(Webster et al., 2013). One of the significant risks that face the operational workers is weather and therefore work strategies should take into account information from national meteorological; advice that national meteorological offices can provide to wind farm operators should take into consideration; In Finland, since it is proximity to the arctic circle, climate atmospheres can make it tough for workers to carry out certain tasks, such as the operation of wind turbines; moreover to ensure that workers can take suitable measures to prepare and protect themselves(Webster et al., 2013).

Warning of anticipated weather conditions such as ice formation is provided constantly from the harsh weather testing network in Finland ( Harsh Weather Testing Network, 2011). ice Fragments fall or be thrown from the rotor when this ice melts or is shaken off the rotor it causes a serious problem for the workers especially operational staff as they work near the turbines so when significant risk is believed to happen, the following procedures are recommended; stop the operation of turbines during the ice accumulation or applying turbine with special features which prevent ice accretion or change turbines places to more safe areas; besides operational staff should be more conscious of the conditions that lead to ice accretion on the turbine(Morgan et al., 1997).

Another dangerous element in the operation for the marine wind farm(offshore farm) is the transfer of personnel to the turbines because the turbines can be accessed only by boat or helicopter as the reach to the turbines is dependent on the sea state; if waves increase in magnitude while work is being conducted workers might find themselves trapped on a turbine structure (Webster et al., 2013). The broadcast platform can accommodate personnel indefinitely, and in extreme conditions, this fact should be kept in mind when designing for human safety. The need for personnel, which must be based on a central transmission platform, will increase if operations are moved further from the coast and the logistics of moving people on land becomes more difficult.

Possible design requirements for stationary personnel on transmission platforms in inclement weather should also be taken into consideration(Webster et al., 2013). A report by the (CMOH, 2010) in Ontario noticed potential health risks that involve shadow flicker, which occurs when the blades of the turbine rotate in cast shadows and sunny conditions, nevertheless, the CMOH deductions this as a potential risk by 3 % of people with epilepsy are photosensitive and that most turbines rotate at a speed below 5–30 Hz, which is the flicker frequency that usually triggers seizures. The CMOH also discounts the ill health effects of wind turbine-generated electromagnetic fields (EMFs)(Webster et al., 2013). However (Rideout et al., 2010) indicate that the low percentage of EMFs which come from wind turbines do not represent any risk.

Maintenance issue

After the tower building is finished and running. Several maintenance actions must happen in the life structure of the tower and the routine maintenance period for a modern wind turbine could take 40 hours a year; however, the issue has a relation to design especially as the installation may have a design life of 20 years, and there are some pieces of the installation like gearboxes, which need to be repaired or changed; but nowadays, gearboxes have to be changed from 7 and 11 years into service(Webster et al., 2013). The author also states the chance to exposure to occupational health risks is depends on the time spends working on and maintaining a wind turbine, the more time worker spends the greater the exposure to OHS; moreover, the skill shortage technicians in some EU countries, labors employed by some of the bigger companies maybe need to do maintenance work in different countries, frequently working away from home for a long time. Maintenance works contain tasks like, lubricating parts, cleaning blades, full generator overhaul, repairing electrical control units, and replacing components, these may be more repetitive tasks which means that maintenance technicians become familiar with the risks and the procedures for working at heights, interacting with electricity. the industry tends to concentrate on gearbox failures, as these cause wind turbines to be non-operational for the longest period.

Regarding gearboxes, there has been some argument about improving their reliability to reduce the instances of workers having to carry out maintenance, and the new turbine designs are opting for direct drive, which does away with gearboxes altogether and about electrical risks, it looks that going over the nacelle may have the risk of injury from sparking and electric shocks or even electrocution, especially on smaller, commercial-scale turbines that do not have brakes or shut-off mechanisms to prevent the turbine from accidentally being switched on through maintenance actions; so, it is necessary to identify, block, detach and free energy sources present in the wind turbines before maintenance work happened(Webster et al., 2013). besides Maintenance work around the nacelle is involved risks associated with moving parts should the nacelle turn, hot parts causing burns and high-voltage cables; If moving parts of the turbine-like gears and blades are not protected well, they will cause severe injuries, such as crushed fingers or hands, amputations, burns or serious eye injuries; therefore a high level of moisture ingress protection should be offered which could protect the equipment from damages(Webster et al., 2013).

Maintaining turbine blades will also involve operations such as buffing and resurfacing, which may expose workers to harmful gases, vapors, and dust that could affect the respiratory system causing asthma or another disease; when inside the turbine, adequate ventilation should be provided to reduce inhalation hazards; If the ventilation alone is not adequate, then workers may also need to use appropriate respirators; the use of respirators may give a false sense of security and workers should understand the limitations of the respirators. For example, during heavy exertion, the respirator seal is often compromised, which allows the hazardous substance to enter the breathing zone without being filtered through the gaps between the respirator and the wearer’s face(Webster et al., 2013). Hence workers must be trained in the proper use of respirators, counting storage, and maintenance. It is particularly important to monitor workers’ exposure to gases and dust during work in confined to ensure their safety.

Discussion

This paper has tried to bring together relevant hazards and risks related to the wind farm industry by using data from national wind energy trade bodies, reviews, and other stakeholders. But it was evident that the quantity of information available is somewhat sparse and vague. Because there is a lack of experimental data on risk exposures to workers such as most research concentrate on public safety or businesses within the wind sector tend to be guarded not only at a recruitment and training level but also at an operational level; the operational data of turbines are kept confidential by the manufacturer; Some wind energy operators share between themselves mainly between members of wind energy trade associations their data on occupational incidents and accidents but do not make this information public, so limiting possibilities for OSH and occupational hygiene actors to contribute to research and action to improve occupational health conditions in the sector; moreover, the debate on the adverse effects of wind turbines on human health and the environment still continues (Webster et al., 2013).

In 2012, the American Wind Energy Association, Australia’s Clean Energy Council, the Canadian Wind Energy Association, the European Wind Energy Association, the Global Wind Energy Council, and Renewable UK said: ‘As a responsible industry that has been delivering clean electricity for more than 30 years, we collectively continue to engage with experts in science, medicine, and environmental health to monitor on-going credible research in the area of wind turbines and human health…the balance of scientific evidence and human experience to date clearly concludes that wind turbines are not harmful to humans’ (Casey, 2013). This statement is not cover the occupational health impact that the industry has on its own workers but on the effect of wind energy on public health; so the Caithness windfarm information forum has now involved human health incidents in its accident database, including incidents associated with turbine noise, shadow flicker and so on; however there were six incidents impacting on human health in 2012 and 11 up to 31 March in 2013; besides, more reports are predicted to rise significantly as extra turbines are constructed; more occupational-based research is required on new combinations of traditional risks and hazard in new environments, noise, vibration, electromagnetic radiation, use of dangerous substances, vibroacoustic disease, and wind turbine syndrome; since the number of accidents and ill health incidents that have been reported and the hazardous activities to which wind energy workers are exposed(Webster et al., 2013).

Conclusion

The future of wind turbines is still unknown. According to Vestas, the company which produced the first turbine in 1979, the operational lifetime of an active wind turbine can be 30 years or longer(Webster et al., 2013). In 2010, so few turbines have been decommissioned but there are still first- and second-generation wind turbines in operation, that are repowered and still used. The author states that technological developments in the design and building of wind turbine blades have extended the life of several wind turbines, despite the earliest generation because they are less efficient and it is expected that in the coming years there will be an increased level of withdrawal activity besides there is no clear guidance to occupational risks in the place and the national trade bodies are still working in improve the standards within the industry by producing best-practice occupational safety and occupational hygiene recommendations, however; there is still a clear need to develop guidelines or global standards for OSH management to guarantee a holistic approach from a life cycle view. Moreover, The European standard EN 50308: 2004 Wind turbines - protective measures - design, operation and maintenance requirements; is currently being updated and this standard is expected to ensure that OSH is taken into account as soon as possible; from the beginning of the life cycle of wind turbines and the all workers entering the industry(Webster et al., 2013). Which minimizes the risks and ensures the safety of workers for the wind farms industry.