JEC COMPOSITES MAGAZINE - Issue #54 - January 2010 - 28

FEATURE “Wind Energy” Blade length: top-end limits are not set by the materials BASF has developed new epoxy resin systems for fibre-reinforced composites that are tailored specifically to the production of rotor blades for wind turbines. The systems increase productivity by allowing for significantly shorter cycle times. DR. GREGOR DAUN RESPONSIBLE FOR EPOXY SYSTEMS BASF, INTERMEDIATES DIVISION he boom in wind energy generation continues unabated: at the end of 2008, the total capacity of wind turbines worldwide amounted to 120 gigawatts (GW), representing an increase of nearly 30% compared to 2007. In their report “Offshore Windparks in Europe”, accountancy company KPMG concluded that the wind energy industry is currently one of the sectors showing the most dynamic growth worldwide. Eighty countries are already using wind for electricity generation. “Wind power already generates more than 1.5% of total electricity production,” reports Stefan Gsänger, Secretary General of the World Wind Energy Association (WWEA, Bonn, Germany). As in the past, Germany occupies first place, followed by the USA, Spain, China and India. These countries account for three-quarters of the installed capacity. The WWEA believes that it should be possible to fully meet the electricity requirements of the world population with wind and other renewable resources by 2040. According to Gsänger, “a rapid expansion of wind energy would be the correct answer to the current financial crunch and ongoing energy crisis.” T Wind turbine at BASF’s Verbund site in Antwerp, Belgium UpWind, which started in 2006 and will run until 2011, is following this vision. “UpWind is the flagship project for European research cooperation in the field of wind turbine development,” explains Project Manager Peter Hjuler Jensen of Risø National Laboratory (Technical University of Denmark). The new giants are intended in particular for offshore use, because the wind blows more strongly and consistently there. The length of rotor blades is increasing, since a blade with twice the length covers an area that is four times the size, and thus can capture four times as much energy. At the same time, a blade with twice the length is generally four times as heavy. Whilst a 30-m blade weighs 4 to 5 metric tons, a 60-m one weighs in at nearly 20 metric tons. In spite of these increasing weights, the technical limits have nowhere near been reached, even with the use of new materials such as carbon-fibre composites. There are design concepts for 70-m blades and test rigs for blades of up to 90 m. At around 60 m in length, the possibilities for glass-fibre reinforcement have been pretty much exhausted. Beyond this, carbon fibres are more often used, but they cost around five times as much. At the moment, two trends are dominating the development of wind energy – turbines are growing ever larger in order to generate more power at individual locations, and wind power is moving offshore. Repower and Enercon are the first manufacturers to offer 5 and 6 megawatts (MW) output, respectively. Rotor diameters are correspondingly impressive. The Repower 5M turbine has a rotor diameter of 126 m, for individual rotor blades 61.5 m long. The Enercon E-126/6 MW has similar dimensions: rotor diameter 127 m, blade length 58 m. However, these immense dimensions are apparently not the limits of what is possible. Enercon is already investigating whether, based on the E-126, 8 MW of output can be achieved. Other designers are currently considering 10, 12 or even 15 MW. The target for 2020 is 20 MW. The European project jec composites magazine / No54 January 2010

JEC COMPOSITES MAGAZINE - Issue #54 - January 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #54 - January 2010