In the last years the utilisation of wind power contributed a major share to the growth of electricity generated from renewable energies. However, wind alone is not enough – in order to generate electricity all plant components must function optimally – preferably without friction or any failures.

Actually, wind power plants are highly complex systems exposed to extreme requirements. The ADDINOL Lube Oil GmbH, seated in Leuna, Saxony-Anhalt, has developed special lubricants for these particular operating conditions. The renewable energy sector has been provided for by the lubricant expert since about 10 years and established as important business segment including lubricants for hydroelectric and pump storage plants as well as biogas engines and wind turbines.

Tradition and innovative ideas make up ADDINOL’s seminal corporate concept according to Frank Merbitz, Head Application Technology. Although ADDINOL does not run its own refinery any more, some 600 lubricants are developed, manufactured and sold in more than 70 countries around the globe. "Because of the good mix of automotive and industrial lubricants and an export share of about 50 percent the worldwide economic crisis did not affect us as much as other companies of our branch", judges Merbitz. The high-performance lubricant business certainly had a share in this.

In all weathers
If a wind power plant shall make some profit, it needs to run without any friction literally. ADDINOL Eco Gear S with the so-called Surftec® technology is devised as high-performance industrial gear oil improving economy (as already hinted at in the product’s name) and operational safety of a wind power plant clearly. With Eco Gear S based on synthetic components the gear’s friction loss can be reduced by approximately five percent as proven by a study of the Research Centre for Gears and Gear Unit Design of the Technical University of Munich (FZG). While the general friction losses of ADDINOL Eco Gear 320 S do not differ significantly compared to conventional gear oils, load related losses can be reduced by up to 41 percent.

According to product manager Steffen Homberg lubricants are faced with real challenges in the gears at up to 150 metres height. The powertrain is exposed to strong and varying loads. This is true especially for the main drive, the heart of the plant, where the gear needs to transmit immense and dynamic forces and torques and to ensure the reliability of the whole plant. "If there is no wind, temperatures in the plants will fall, but when the blades start rotating and there are temperatures of minus 25 degrees in winter, the oil must lubricate immediately and minimise the high loads prevailing at cold-starts by a reliable lubricating film", describes Homberg the exceptional conditions. During summer at higher temperatures the same oil must provide dependable lubrication as well. "Our product does not only meet the requirements of gear and plant manufacturers but has also proven in practical application", according to Homberg.

For their gear oils ADDINOL guarantees a lifetime of at least four years; during this time the oil’s condition is monitored carefully by regular oil analyses. Immediately after the oil change a first sample is taken to check the condition of gear and oil; this sample serves as reference for further samples taken over the whole application period.

The long-term warranty is of particular importance to the plant operators as long lifetimes and oil change intervals contribute to the economical operation of the plants. At the same time it has positive effects on resources, component wear is decreased and efficiency is improved. "The friction-reducing effect of ADDINOL Eco Gear increases with unfavourable operating conditions. According to the FZG Eco Gear enables efficiencies which are usually only achieved with EHD lubrication", says Homberg.

Tightrope walk: filling
There are several service companies for the filling of wind power plants in Germany. The required gear and hydraulic oils are transported in IBC per truck to the various locations and pumped through hoses to the pods at a height between 60 to 160 metres. "Actually, two hoses are needed: one for pumping the old oil down and one for filling the plant with the new oil; they are pulled into the pod by the help of a crane", describes Stephan Eckhard, Head of Oil Service at the WINDPARKSERVICE GmbH.

Depending on its size a wind energy plant requires between 100 and 500 litres gear oil. If it is equipped with a hydraulic pitch system for adjusting the rotor blades about 50 to 300 litres hydraulic oil are needed additionally. Furthermore, wind energy plants possess two to eight azimuth drives (drive motors) filled with 10 to 20 litres gear oil each. These drive motors are responsible for turning the pod into the right direction. Plants with electronic pitch systems have one drive motor for each rotor blade containing about 5 litres gear oil. Peter D. Claußen, working in this business with C&D Ölservice GmbH since ten years, estimates that oil quantities will not increase considerably in future. Many new plants even do not need any main gear any more but possess a multipolar generator driven directly.

Offshore technology means a new challenge for lubricants as well. "Additional and stronger environmental loads need to be taken into consideration here and also the impact of salt water", says Homberg. Suitable lubricants are being developed but so far there are only a few wind parks in the open sea. All in all, Frank Merbitz sees growth potential for this special market.

ADDINOL – yesterday and today
ADDINOL’s history began in 1936 when the Mineralölwerk Lützkendorf was founded in Krumpa (Saxony-Anhalt) and became one of Germany’s largest refineries for the production of fuel and lubricants. Research and development were a prime focus from the very beginning. Back in the 1980s the Mineralölwerk Lützkendorf possessed an international competence centre for lubricants.
High-performance lubricants of the Mineralölwerk Lützkendorf, as for instance the engine oil ADDINOL Super, were a synonym for quality and progress.  ADDINOL – Additives in Oil – was one of the most famous brands of the GDR and became the company’s name after the German Reunification. In 2000 ADDINOL Lube Oil GmbH moved its headquarters to Leuna/Saxony-Anhalt and in 2007 re-started their own production at the chemical site Leuna. Today the company is represented in more than 70 countries all over the world and exports nearly 50 percent of its production. The last years saw a two-digit sales increase.

German article published in Brennstoffspiegel und mineralölrundschau 02/2010 (view German article here)