Products tested on Vestas turbines

Mardyck, which lies outside the industrial area of Dunkirk, is swept by the winds of Northern France's plains. This makes it an ideal place to produce wind power, explaining why Total chose it to build its wind farm in September 2003. The farm has two 2-megawatt turbines built by Vestas (the world leader in this market), two 2.5-megawatt Nordex turbines, and the "big sister", a gigantic General Electric wind turbine. This one alone weighs 250 tons; its blades and nacelle tower no less than 100 meters above ground, and it generates 3.2 megawatts.

Air power: a heavy lubricant consumer

Air power Wind turbines are complex mechanical installations which require three types of special iubricant: for the hydraulic circuits and brakes, greases for the slewing rings and bearings, and lubricants for the speed-increasing units. These units, which multiply the blades' rotation speed, are particularly heavy lubricant consumers: each casing takes 350 to 700 litres. When the wind moves a wind turbine naturally, its blades rotate at about thirty revolutions per minute. With the speed- increasing unit, the generator can reach speeds of 1 ,500 rpm. Total has invested considerable R&D in this field. It has developed two synthetic oils; Carter SH 320, a polyalphaolefine chemical-based lubricant, and Carter SY WM 320, an oil based on a compound known as polyalkyleneglycol.

A full wind-power product range

Lubricants in the speed-increasing units have to fulfill several different roles. They need to avoid fatigue- related wear on the gears and corrosion on the gears, while also remaining fitter-friendly, non-foaming, water-resistant, and harmless to operators. Wind turbines last for some twenty years and require oil changes about every three years -which is another complex operation. At Mardyck, for instance, the casings are between 80 and 100 meters above ground, and are only accessible through the inside of the mast.

This farm is a test site for us. We developed the lubricant formulas on the basis of wind turbine manufacturer specifications, tested them in the laboratory and had them validated. Now we need to test them for two years in service, according to procedures drawn up in collaboration with the manufacturers, before we can expect their certification. Total Lubricants is currently working on other oils for these wind turbines that will enable it to offer a comprehensive wind-power range.