The Covid-19 pandemic had put a halt to wind energy installation. Despite this, the world is expected to have added about 65 GW of wind energy in 2020, as per the International’s Energy Agency’s estimates. Going into 2021, capacity additions in the wind sector are projected to touch 68 GW. Although wind turbine technology has seen major advancements over the years, it is equally important that efficiency of the existing turbines is maintained. With time, wind turbines that were installed in the initial years of the past decade, or even before that, have aged and require intensive operations and maintenance (O&M). There have been many innovations in O&M techniques to cut costs and reduce human intervention.
New world order
Wind turbines have several moving components such as gears, blades, hydraulics and brakes, which need to be constantly monitored and maintained to maximise output. These O&M services include costs associated with insurance, preventive and corrective maintenance, spare parts, and administration, of wind power plants. Wood Mackenzie has estimated that about $15 billion was spent on O&M in the wind power sector during 2020, which is about three times the cost of solar plants. For a new wind turbine, these could represent 10-15 per cent of the total levellised cost per kWh of electricity produced over its lifetime and this figure could grow to about 20-35 per cent as the turbine approaches decommissioning. The US Department of Energy’s Annual Energy Outlook estimates this value to be about $26 per kW per year, but based on developer data, this value has been estimated by the Lawrence Berkeley National Laboratory at $59 per kW per year.
In a study by IHS Markit on wind farms in North America, an increasing trend of O&M expenses was observed; it was projected that by 2021, O&M costs will exceed capital expenses. This can be attributed to the increased variable costs of older wind turbines, which are low on efficiency and more prone to failure.
As the pandemic hit China in the early months of the year, it was the first to close all manufacturing, distribution and other related services in the wind energy sector. This created supply chain problems for spare parts and hampered maintenance services for a large part of the wind assets in the world. The bigger implication of the pandemic was an increase in administrative costs for ensuring that physical distancing protocols are followed. The health and safety of technicians was made a priority, and they had to follow isolation measures while taking occupational risks. These factors called for automation in O&M services for wind turbines so as to limit manual intervention.
Automation in wind O&M
Until recently, the inspection activities associated with the O&M of wind power plants were carried out manually, twice a year, by turbine operators using cranes. However, this practice may not be practical if failures or malfunctions are to be detected at early stages. The challenges of regular upkeep are further amplified in the case of offshore wind projects as they are increasingly being developed in deeper waters, with larger turbines of 10-12 MW each. In order to address such issues, it is important to make automation and digitalisation a crucial part of wind O&M.
The most prominent development in the wind O&M space is the emergence of advanced condition monitoring techniques. As opposed to manual checking of turbines, these techniques generate real-time data on vibrations, acoustics, temperature, speeds, etc., and can help predict potential failures. The progress of IoT-based technologies such as the mobile video supportive system (MVSS) has taken this one step further. MVSS is a platform that notifies maintenance experts on potential failure areas so that they can act immediately. This technology reduces the downtime by 10-20 hours and, in turn, improves the efficiency of the wind power plant. Further, these systems ensure that technicians are sent to the site as per need and not just for routine check-ups.
In colder parts of the world such as Europe and Canada, ice gets accumulated on wind turbine blades, resulting in reduced power output and increased rotor loads. To prevent this, Canada-based company Clir Renewables launched a programme to detect such incidents based on probability analysis algorithms using past power generation trends.
It is also important to aggregate the real-time data generated from wind parks to form databases for further analysis. On the basis of this, operators can get better estimates on failure rates, downtime and resource requirement. Further, comprehensive databases can help in generating accurate forecasts for power generation as wind turbines age.
Wind power plant operators have also been exploring the use of drones to carry out supervision and inspection. Although this technology is at a nascent stage, its implementation has picked up pace over the years. For instance, in May 2019, Vestas signed a deal with unmanned airborne vehicle supplier Sulzer Schmid and blade service provider WKA for the inspection of blades on 1,250 turbines in Sweden and Finland. The use of drones was necessary to carry out repairs in less than 12 weeks as otherwise the inspection would have had to be carried out manually in the less windy summer months. In October 2018, Siemens Gamesa Renewable Energy (SGRE) signed an agreement with drone manufacturing company SkySpecs for the inspection of its wind turbine fleet. SGRE is reportedly working on rope robotics, a technology wherein robots are designed to travel over the length of the blade. In addition to monitoring the health of the blades, the robots can perform basic service tasks including cleaning and polishing. Drone providers have also introduced technologies such as laser navigation to provide angle measurements for high-precision work close to structures.
In addition to drone-based technologies, many other innovative wind turbine solutions have emerged. Although light detection and ranging (lidar) tools are traditionally used at the early stages of assessment of a potential wind power project, their operational applications are now gaining traction. In such a situation, developers can access information on wind conditions so that more informed decisions on tuning and control can be made.
In 2018, GE developed a ground-based blade inspection tool called Sabre. The device, which is positioned on a truck at the base of the turbine, uses thermal imaging and acoustic spectral analysis to detect cracks, delamination and defects in the turbine bonding. This helps in carrying out inspection in just about 15 minutes and is done even when the turbine is running.
Although O&M costs for offshore wind turbines are substantially higher than for onshore wind turbines, they are expected to fall with the widespread deployment of offshore wind around the world. This large-scale deployment of offshore wind has further necessitated the need for automated O&M. To this end, companies such as Anybotics, a Swiss robotics firm, introduced Anymal, a four-legged robot that is designed to detect thermal hotspots and oil and water leakages in offshore wind power plants. It can be operated from onshore control centres and is equipped with visual and thermal cameras, microphones and gas-detection sensors to send real-time data on turbine performance.
For carrying out repairs in offshore wind power plants, ropes and access platforms have been used by technicians but this exposes them to risks in times of high winds and waves. Scotland-based Span Access Solutions has been working on a tower-mounted access base to ensure easier and safer inspection of blades. The technology is still in the works and has received a grant of GBP 830,000 from the Government of the United Kingdom.
Status in India and future outlook
India has installed a wind power capacity of about 38 GW and aims to increase this to 60 GW by 2022. In the past four years, the capacity has increased by about 70 per cent, which indicates that many turbines are relatively new. However, India still lags behind in the adoption of automated O&M for its wind power plants vis-à-vis other countries. The pandemic, too, has had an impact on O&M services in the country, given the added safety precautions that technicians have to follow. As the scale of projects increases, existing wind turbines age and offshore wind evolves, O&M automation would become imperative. At present, automated O&M services are quite expensive for widespread adoption but this could change. Just as tariffs have fallen with the increased development of wind power plants in the country, a similar pattern may be observed for O&M costs as well.
The trends in the O&M segment have shown that the costs associated with wind turbine upkeep are only expected to increase in the years to come. Even though newer turbines will have better efficiency and will be less prone to damage, the older turbines will need more attention. Technology has come a long way in helping developers and turbine manufacturers obtain real-time information on faults in their systems and at the same time minimise human risk. Although the adoption of O&M automation has been slow, it is up to original equipment manufacturers to recognise its value and increase uptake, so as to build an O&M market that reaps the benefits of the digital era.