To start with, ENERCON systems still featured gearboxes. However in 1992, the changeover to gearless technology came about with the first ENERCON E-40 / 500 kW. This innovative drive system with few rotating components ensures nearly friction-free energy flow providing outstanding performance and reliability. Mechanical stress, operating and maintenance costs are reduced, and the system’s service life is increased.
Today, all Enercon wind energy converters are based on the company’s tried and tested wind turbine concept. Over the past years, new system generations have evolved through constant sophistication of existing components, providing customers with state-of-the-art products. One example of the latest technological innovation is the new rotor blade geometry introduced in 2004. It significantly increases revenue, minimises noise emission while considerably reducing load impact on the wind energy converter.
All Enercon systems feature a grid connection system which fulfils current grid connection requirements and can thus be easily integrated in any supply and distribution structure. Enercon’s concept not only offers solutions for normal operation such as reactive power management and voltage control but also for critical situations resulting from network short-circuits or bottlenecks.
Since then Enercon has been setting new standards in technological design for more than 25 years now. With more than 18,000 wind turbines installed in over 30 countries, Enercon is also recognized as one of the leading manufacturers at the international level. Research and development, as well as production and sales are constantly evolving. The company’s objective for 2010 is an export share of more than 60 %, gradually increasing over the years to come.
Drive system
Rotor blade concept
When it comes to yield, noise emission and stress minimisation, ENERCON’s rotor blade concept sets new standards in the wind energy sector. Because of their modified shape, the blades not only draw energy from the outer edges but also use the inner radius of the swept area, considerably increasing power output. The new rotor blades are also less susceptible to turbulence and provide an even flow along the entire length of the blade profile. In addition to the new design, the blade tips have also been improved to reduce noise emission and increase power output. Turbulence at the blade tips due to overpressure and underpressure is effectively eliminated in the rotor plane. The entire length of the blade is therefore utilised without any loss of energy caused by turbulence. The blades’ high efficiency is reflected in power curves taken on all ENERCON wind turbines where power coefficients (Cp) of more than 0.5 are achieved.
Advantages of ENERCON rotor blades:
Higher efficiency due to modified blade design
Less noise emission due to optimised blade tips
Longer service life due to reduced load impact
Easier transport due to streamlined blade design
ENERCON rotor blades are manufactured with a vacuum infusion process using the so-called sandwich technique. Glass fibre mats placed in the mould are vacuum-impregnated with resin by means of a pump and a hose system. This method eliminates air pockets in the laminate. In order to efficiently protect the rotor blade surface against weather elements such as wind and water, UV radiation, as well as erosion and bending loads, the rotor blades’ protective finish is composed of gel coat, filler, edge protection and top coat using only solvent-free two component polyurethane compounds in the entire system. To efficiently withstand wind loads over the entire usage period, ENERCON rotor blades have an extremely large flange diameter. The double-row bolt connection specially developed by ENERCON for large wind turbines also provides additional strength by creating even load distribution. This is an important factor, particularly in extreme wind locations with considerable stress fluctuations.
Direct Drive
The drive system for Enercon wind energy converters is based on a simple principle: fewer rotating components reduce mechanical stress while at the same time increasing the equipment’s technical service life. Wind turbine maintenance and service costs are reduced (fewer wearing parts, no gear oil change, etc.) and operating expenses lowered. The rotor hub and annular generator are directly interconnected to form one gearless unit. This rotor unit is then mounted on a fixed axis, the so-called axle pin. Compared to conventional geared systems with a large number of bearing points in a moving drive train, ENERCON’s drive system only requires two slow-moving roller bearings due to its low direct drive speed.
A few years ago only the rotor hub was made of cast steel. However, today, with the use of modern spheroidal graphite cast iron, it is possible to manufacture other major components such as blade adapters, axle pins and main carriers with this process. ENERCON carries out advanced development of its cast components in close collaboration with the foundries. All cast components are drawn with a 3D CAD system and calculated using the finite element method to check for strain increases at critical points.
During the entire prototype phase, the designer tests and optimises performance. In order to guarantee the identification and traceability of each cast component when the goods are received at ENERCON, each part is given its own specific barcode from which the serial number can be obtained in the event of quality issues for example. Cast components are only released to the next stages in ENERCON’s manufacturing process once comprehensive quality testing has taken place, thus guaranteeing high ENERCON quality standards in the cast component supply sector. Since mid-2009, ENERCON has had its own exclusive manufacturing possibilities for the cast components of its wind turbines.
Grid integration & Wind farm management
ENERCON annular generator and grid management system
Today, global energy supply without wind energy would be difficult to imagine. Given the ongoing rise in electricity demand, it is more than ever our responsibility to guarantee secure power supply. Wind energy has come of age and in the years ahead the development of wind energy will play a major role in the race to satisfy demand. To accomplish this, one of the vital factors will be the capability of wind technology to be integrated into existing power systems. Stringent regulations imposed by grid operators require wind turbines and wind farms to fulfil power plant properties which necessitate highly sophisticated and flexible technology. The new version of the German Renewable Energy Sources Act has put the necessary framework in place for this. In cooperation with German and international utilities, ENERCON has already made major advancements in developing practical grid connection solutions for our wind turbines and wind farms to offer the desired and legal system services to the grid. Also in the future, ENERCON will continue to set the benchmark in the field of integrating wind turbines in electrical grids, guaranteeing a stable, profitable and highly qualitative supply of wind energy.
Amongst other features, the annular generator is a key component in ENERCON’s gearless wind generator design. This low-speed synchronous generator is directly connected to the rotor. Generator output voltage and frequency vary with the speed and are converted via the ENERCON Grid Management System to be fed into the grid.This allows rotational speed control to be optimised; the annular generator is thus perfectly independent of the grid. By adjusting or ‘pitching’ the blades and through electrical excitation via the turbine control system, rotational speed and power output are constantly checked and optimised. The electrical power produced by the annular generator passes into the ENERCON Grid Management System which comprises a rectifier, the so-called DC Link and a modular inverter system. The inverter system defines the essential performance characteristics for output to the grid and ensures that the power output corresponds to grid specifications. Here in the inverter system, voltage, frequency and power are converted accordingly. Via the transformer, inverter voltage (400 V) is stepped up to the appropriate medium voltage required by the grid or the wind farm network.
ENERCON wind turbines are equipped with a Grid Management System designed to meet the latest grid connection requirements. This facilitates integration in any transmission and distribution network. The Grid Management System offers numerous performance features e. g. reactive power management and optimum contribution to maintaining voltage levels. Essentially, ENERCON wind farms behave very much like power stations or in some aspects even exceed their performance. ENERCON is the first manufacturer worldwide to have received certification confirming these power plant properties. These product and unit certificates as well as validated simulation models will in future be used as a basis for the wind farm certificates required by the German Association of Energy and Water Industries guidelines and the latest Renewable Energy Sources Act.
Chronology
1984
ENERCON GmbH founded by Aloys Wobben
Development of first ENERCON wind turbine E-15/16 (55 kW)
1988
Development and installation of E-17/80 kW and E-32/100 kW
1991
Completion of first own production facility
1993
Launch of E-40/500 kW series: first gearless WEC
Construction of first rotor blade production facility (AERO)
1995
Installation of E-66/1.5 MW prototype
1996
Purchase of production site in Sorocaba
1998
Acquisition of SKET Maschinen und Anlagenbau GmbH, Magdeburg
Development of E-66 production site in Magdeburg
2000
German Environmental Award presented to company owner Aloys Wobben
Development of WEC Turmbau GmbH in Magdeburg
Takeover of steel manufacturer Kockums Industrier AB, Malmö, establishment of EWP Windtower Production
2001
Founding of a new wind turbine production facility in Magdeburg-Rothensee
2002
Set-up of new rotor blade production facility in Turkey
Commissioning of E-112 prototype in Egeln near Magdeburg
2003
Launch of serial production of E-112 rotor blades in Magdeburg, Germany
2004
Installation of two E-112 turbines in Wybelsumer Polder near Emden and nearshore E-112 in the Ems River
2005
Construction of a concrete tower production facility (WEC Turmbau) in Emden
Expansion of worldwide production area to 380,000 m²
Enhancement of E-112 to 6 MW wind turbine
Commissioning of E-82/2 MW prototype
2006
Commissioning of E-20/100 kW and E-53/800 kW prototypes
Advancement of E-112 to E-126 MW wind turbine
Further development of the wind turbine E-112 to E-126
2007
New headquarters building in Aurich
Completion of prototypes E-126
Launch of construction of production sites in Viana do Castelo (Portugal)
2008
Christening of "E-Ship 1" in Kiel
Aloys Wobben receives Rudolf Diesel medal
Launch of rotor blade and tower production in Viana do Castelo
2009
Inauguration of mechatronic and blade production factories in Viana do Castelo (Portugal)
Commissioning of ENERCON hydropower plant in Raguhn / Saxony Anhalt
Inauguration of new WEC Turmbau production site in Magdeburg
2010
Inauguration of Europe`s most modern foundry (Gusszentrum Ostfriesland GZO)
Expansion of product range E-82/2.3 MW, E-82/3 MW and the E-101/3 MW
Maiden voyage of E-Ship 1
