Re-inventing the wind turbine Mervento

RE-INVENTING THE WIND TURBINE

Mervento is a global leader in the design and manufacture of multi-megawatt wind turbines for onshore and offshore applications. Philip Yorke talked to Jarmo Saaranen the company’s CEO, about its unique direct-drive technology and ambitious plans for the future.

Mervento was founded in 2008 as a division of the leading Finnish engineering office, Enmac, which has been involved in the development of directdrive wind turbines since 2004. Mervento’s advanced wind turbine technology was developed for cold climate locations with IEC class II wind conditions and designed to operate in temperatures ranging from –30C up to +40C. At Mervento, the entire turbine power train is tested in the company’s partner’s assembly plant and transported as one complete module.

Mervento has also developed a unique turbine erection system, which makes it easy to move the power unit from site-tosite and enables in the near future the lifting of the nacelle, including the hub, to elevated hub heights of up to 200 metres. Mervento’s high-gain rotor blades can be lifted bladeby-blade with a special winching system, which makes it possible to erect the wind turbines without the need to employ large cranes, which is a major cost consideration.

Innovative, cutting-edge technology

Mervento’s advanced wind turbine designs boast more than twenty new innovations never seen before in the wind turbine industry. With its 3.6-118 turbine, Mervento has delivered the world’s best power curve to date in the power class 3-4MW. This has been achieved by the introduction of very large diameter rotors at sites with IEC class II wind conditions. All components used in the power train are super-efficient and the fact that the turbine is ‘gearbox-free’ has a profound and positive affect on the powercurve trajectory itself. Furthermore, the optimised blade design and the cyclic pitch function, designed for optimised tip-speed ratio has resulted in Mervento being able to supply the industry’s most silent-running wind turbine motor.

Saaranen said, “Almost every aspect of our hyper-efficient wind turbines has been developed in-house. Our main goal has always been to produce high-energy efficiency with excellent reliability and to drive down the cost of energy production. We believe that our wind turbines are the first ever to be developed from the outset to operate in the coldest climatic conditions, such as those experienced in the Nordic countries of Finland, Sweden, Norway and Iceland.

“One of our strengths is our ability to licence out the whole wind turbine unit or just a part of it. Our integrated structures and solutions make our turbines the most efficient and innovative on the market today, with our systems being totally different from those of our competitors. Another important

point is that in the Nordic regions there is a lot of forest terrain, which in turn creates very turbulent wind conditions. All our turbines have been designed to operate efficiently and reliably in these harsh and diverse wind conditions.

“We are very active in the class II wind turbine sector, which is a much bigger market than Class I and our units are designed for both offshore and onshore applications. In contrast to the freezing conditions in the Nordic countries, we also cater for the needs of energy companies that operate in the very hottest regions of the world where you have a lot of abrasive wind and sand and big temperature changes between night and day running operations.”

Saarenen added “We have now had our products in testing for two years and more than 60 of our wind turbines are now in Letter of Intent phase. Having proved the superior efficiency and reliability of our advanced wind turbine products, we are now entering a new growth phase. Therefore we are currently seeking our ‘next-phase financing’ funding from large corporations in related industries and we are also interested in offering licences to companies that operate outside of our own main market areas. We believe that the inherent strengths in our proven designs and

low operating and maintenance costs offer a most attractive basis for future investment in Mervento technology”.

Combining high efficiency with low O&M costs

Mervento’s unique direct drive system and medium voltage permanent magnet generator, in combination with its full-power converter, significantly reduces reliability issues. Eliminating the need for a gearbox is a major leap forward in minimising dayto-day operation and maintenance costs. Furthermore, Mervento’s permanent magnet generator has no slip rings and its cooling system is not prone to failure as there are no water-cooling components involved.

Another advanced feature of Mervento’s new generation of wind turbines is the fact that it is the first wind turbine with a hydraulic yaw-system where the actuating system and brake systems are fully integrated. Mervento’s advanced technology also separates the feathering from the collective pitch, with feathering being operated by three individual cylinders and piston accumulators located in the hub. The collective pitch is also operated by three cylinders situated in the main shaft of the wind turbine. The fully fire-proof rotor brake system located in the hub is also hydraulically operated and specially tailored for the Mervento 3.6-118 turbine.

At Mervento all maintenance processes have been planned and integrated into the unit during the design phase, resulting in fast, easy access and servicing, both in the large nacelle and in the ground level turbine station. The company’s integrated turbine controller, CMS condition monitoring system and CBM based maintenance programme is an all-in-one system. Mervento has also developed its own advanced SCADA system, which is able to communicate with the grid operator’s system 24/7.

All these cutting-edge innovations come as standard features in the company’s advanced wind turbines. n

For further details of Mervento’s innovative wind turbines, investment opportunities and customer services visit: www.mervento.com