The ongoing expansion of wind energy is not only important for Germany's energy transition. The operation of wind turbines is also a challenge that promotes the use of innovative technologies and concepts in service. This is why other industries can also learn from it.
Around 30,000 wind turbines are currently in operation in Germany. These can be usefully divided into offshore and onshore installations. This is because the difficulties involved in maintenance and repair differ considerably. Offshore wind turbines make up the smaller part with around 1,500 objects.
The difference between offshore and onshore wind turbines in service
A wind turbine on land generates up to 15 gigawatt hours of electricity per year. This amount is roughly enough to supply 4,400 households with electricity. Offshore plants are usually much more powerful, but also much more demanding in terms of service.
Offshore turbines can deliver up to 67 gigawatt hours per year and therefore supply up to 19,000 households with electricity. This is partly due to the fact that much larger wind turbines are built at sea. However, the wind also has a major influence. The time in which there is enough wind to operate a wind turbine effectively is only approx. 12-25%. Of course, this value also varies onshore depending on the location, but at sea the wind availability usually significantly exceeds the value of 25%.
As a result, operations at sea are far more profitable in terms of performance and turnover. However, service management is also much more demanding here and the costs are also considerably higher in this area. It can be assumed that service and maintenance of wind farms at sea account for up to a quarter of the total costs. On land, costs are more likely to be in the single-digit percentage range.
What are the challenges for the service operation of offshore turbines?
The main difficulty that our service colleagues in the wind power industry have to contend with on the high seas is the difficult accessibility of the turbines, which is why malfunctions and breakdowns are particularly problematic here.
In the best case scenario, service technicians are brought to the system by ship in the event of a malfunction or maintenance. However, due to the often poor weather conditions, this is only possible on 20 percent of days per year possibleas the service ships cannot reach the facilities safely.
It is therefore not uncommon for service technicians to be roped down to their workplace by helicopter along with their equipment, James Bond-style. In this way, operations are possible on around 60% of the day in addition to ship operations. However, due to fog and difficult wind conditions, the systems are not accessible at all on 20% of all days.
Due to the high performance of offshore wind turbines, an outage that occurs during this period is naturally a particular problem, as it results in a major loss of revenue. Service management is therefore particularly challenged to keep the turbines as trouble-free as possible.
How are wind turbines maintained?
As a result of the challenges described above, service in the wind power industry has become a pioneer in the use of remote maintenance technologies. In general, we distinguish between three different types of maintenance: automatic maintenance, remote maintenance and on-site maintenance.
Automatic maintenance primarily involves the use of Condition monitoring for the electronic real-time monitoring of data on temperature, vibrations, pressure states and other measured data from the systems. In many cases, faults can be rectified automatically with the help of condition monitoring. In difficult weather conditions, for example, the wind turbines automatically turn out of the wind and the system can also rectify some other faults itself. These include, for example, electronic faults or the compensation of pressure and temperature differences.
However, even if a fault cannot be rectified automatically, a service call on site is not always necessary. Remote maintenance provides the operator with extensive options to avoid costly and dangerous field work. The wind industry is also a pioneer in the use of Predictive maintenanceas the majority of faults in wind turbines can be detected by monitoring just a few components. Thanks to the complete documentation and interpretation of this operating data, on-site operations can be better predicted and planned.
The challenge for the service team
When operating wind turbines, service managers are increasingly concerned with avoiding failures and malfunctions at an early stage. Field assignments, especially on the high seas, must be reduced as they are associated with a number of difficulties. From time to time, service technicians even get stuck on the turbines due to weather changes. For this reason, emergency rations, blankets and other items are stored in each installation so that the stranded technicians can survive there for a few days in an emergency. Even if this happens rather rarely, the operations remain dangerous and expensive.
The accessibility of offshore wind turbines continues to require an excellent Field service-management. It is true that the technicians can also be brought to the plant by helicopter most of the year. However, for cost reasons, it is advisable to carry out as many maintenance jobs as possible on the few days when the workers can get to the site by ship.
The offshore field is therefore a particular challenge for service technicians. They must therefore also meet a stricter set of requirements. After all, not every technician can be expected to abseil down from a helicopter. In addition to technical expertise, there are therefore also conditions relating to fitness and health. This poses a problem in view of the rampant shortage of skilled workers. However, those who meet these requirements can expect a relatively varied and exciting working environment. The latter also applies to onshore wind energy.
What can we learn from the service provided by the wind industry?
There is a lot of talk about condition monitoring and predictive maintenance in mechanical engineering and other areas. However, the number and scope of projects actually implemented often leaves a lot to be desired. With the wind power industry, we have a pioneer in this area that is already one step ahead of other industries due to the requirements typical of the sector.
Of course, systems in mechanical engineering are often somewhat more complex to monitor due to the many different technologies and axes installed, as well as the typically significantly larger number of sources of error, which is why solutions are somewhat more difficult to implement here. Nevertheless, the low availability of suitable service specialists on the labor market also means that we need to think in this direction. This is because assignments have to be planned ever more efficiently so that maintenance contracts can still be serviced at all. It is therefore worth taking a look at the wind power sector, as they not only know which way the wind is blowing on the North and Baltic Seas, but also in terms of innovative maintenance concepts.
Availability guarantees and, at the top level, even output guarantees for a certain performance are possible with Service contracts is also standard in the wind energy sector. This is another area where traditional mechanical engineering is still lagging somewhat behind and will hopefully be able to catch up in many areas in the near future.
