Global wind power capacity reached 281GW in 2012, with the addition of 44GW over the year. Offshore wind power capacity also grew at a steady pace, with 1.3GW of installations in 2012.

More than 187GW of wind power capacity was added during the 2008-12 period, which has drastically increased operations and maintenance (O&M) expenditure, from $3.5 billion in 2008 to $7.3 billion in 2012, at a compound annual growth rate (CAGR) of 15.6%. The increasing age of wind turbines and the failure of components such as blades and gearboxes are cited as the main reasons for these increasing O&M costs.

While the growth of this market is currently restrained by a lack of skilled manpower and the cost of logistics, it is, at the same time, leading to an increase in companies specialising in wind turbine O&M, which, in turn, is decreasing the cost of these services. With all this in mind, the value of the wind power O&M market is expected to reach $19 billion by 2020.

The burgeoning offshore O&M market

Offshore wind attracts higher O&M costs than onshore wind, as higher turbine maintenance, high logistics costs and a lack of skilled manpower make it more of a challenge. Although onshore wind also faces logistics and manpower issues, the impact of these on the offshore segment is higher.

Offshore wind accounted for 8% of the total wind O&M market in 2012, with a market size of $0.55 billion. This figure, however, is expected to grow. It is estimated that revenues from offshore O&M will continue to grow to reach a market size of $5.6 billion, equating to a 29% share of the total wind power O&M market in 2020. The UK, Germany and China will be the largest contributors to this market, with contributions of $1.7 billion, just over $0.63 billion and just under $0.63 billon respectively.

Technology reduces O&M costs

Technology improvement and innovation will continue to reduce wind O&M costs. Digital displacement transmission (DDT), step-up generators and tension control measurement technology for turbine bolts are some of the innovations that considerably reduce wind O&M costs.

DDT technology eliminates the gearbox, which is one of the major causes of repairs in a turbine. It improves power output, increases reliability and reduces cost over the lifetime of a turbine. It’s also scalable, and suitable for high-capacity onshore and offshore wind turbines. Direct-drive wind turbines are more expensive than geared turbines at the outset, but will save money for plant owners in the long run, ultimately reducing the cost of wind power. One of the potential problems DDT will face, however, is the short supply of rare-earth metals used in its permanent magnets.

"More than 187GW of wind power capacity was added during the 2008–12 period, which has drastically increased O&M expenditure."

Enercon, which pioneered the concept of DDT, is now seeing competition from industry majors such as GE, Siemens and Goldwind. The turbine manufacturer’s move towards gearless turbines has been driven by the highly publicised gearbox failures of the last four years, such as those at the UK’s offshore Kentish Flats wind farm and the Lackawanna wind farm in the US.

Nuts and bolts, meanwhile, are simple devices, but failures can be costly. If it is the case, as is suggested, that more than 90% of bolted joint failures are due to insufficient bolt tension in wind installations, then tension-control measurement technology for bolted joints can save millions over the course of a 20-year plant lifetime by reducing bolted joint maintenance by 50%.

The technology was developed by Rotabolt, a leader in bolted joint technology and tension control. This innovative product maintains tension across the bolted joint, thereby minimising O&M costs. The company currently provides tension-control measurement technology to Vergnet for its GEV HP 1MW turbine, and Suzlon for its 1.25MW and 2.1MW turbines.

Predictive maintenance saves money

Predictive maintenance through condition monitoring systems (CMSs) has become a common practice in wind O&M over the last two years. Providing a significant boost to turbine availability, it helps with the monitoring of wind turbines in remote locations. CMSs use vibration sensors on gearboxes, generators, bearings and other components to send signals to the monitoring station, located far from the plant. The vibration data is analysed on a daily basis and provides indicators on possible issues with components. These performance indicators help to predict failures before they occur, making faults easier to fix and improving turbine availability, thus saving costs.

"Predictive maintenance through a CMS costs around $9/kWh a year, resulting in a cost saving of 47%."

Predictive maintenance through a CMS costs around $9/kWh a year, resulting in a cost saving of 47% when compared with reactive maintenance. Predictive maintenance helps owners schedule work and refurbishment, and plan for the ordering of parts based on condition assessments. It also reduces the need for plant visits by technical crew as minor repair issues can be tackled remotely.

Leading O&M markets

The largest wind O&M market in the world, the US, accounted for 23% of the global O&M market size in 2012; however, it is expected that this share will have decreased to 19% by 2020.

Despite being the leader in terms of capacity, China is currently the second-largest wind O&M market in the world because it offers lower costs than the US. China accounted for 21.1% of the O&M market in 2012, and is expected to emerge as the largest wind O&M market by 2020, with 24.7% of global market share.

Germany, Europe’s largest O&M market, accounted for 12.9% of market share, while Spain, the second-largest market in Europe, accounted for 10.7%. The UK, in third place with 7.2%, is expected to surpass Germany as the largest wind O&M market in Europe by 2020, thanks to the huge offshore capacity the country is planning to install. The UK will then account for 15.6% of the global market.

Following the UK was India with 5.3%, while other key international O&M markets accounted for the remaining 19.8%.