The Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) is seeking to optimise wind turbine rotor blade production in order to reduce costs. It is also the leading test centre for extremely large blades, having recently tested the world’s largest, an 80m XXL prototype.
Fraunhofer IWES was established in 2009 by the merger of the former Fraunhofer Center for Wind Energy and Maritime Engineering (CWMT) in Bremerhaven and the Institute for Solar Energy Technology (ISET) in Kassel, both in Germany.
The manufacture of rotor blades is labour-intensive, which means that it is expensive, in high-wage areas such as Europe in particular. They account for around 25% of the total cost of a wind turbine. The five-year BladeMaker project, which began in October 2012, involves Fraunhofer IWES and 18 industrial and research partners in the search for solutions that will help to make manufacture more cost effective, faster and of higher quality.
”International competition is placing rotor blade producers under great cost pressures, which we will tackle with automation,” said Florian Sayer, of Fraunhofer IWES. The goal is to reduce production costs by well over 10%. The project is looking at the complete rotor blade manufacturing chain, including design, materials and manufacturing processes, and helping the change from series to large-scale industrial production. The future establishment of a BladeMaker Demo-Centre will provide a national and international centre for the research and development of rotor blade production.
Rotor blade production currently uses the vacuum infusion process. The first stage involves two moulds or blade halves being reinforced with fibreglass or carbon fibre matting; this is, currently, completed almost totally with manual labour. A vacuum is then generated and a resin injected to bond the mattes. After hardening, the two halves are brought together to form a single blade, which is finished with varnish.
The Fraunhofer Institute’s researchers began with the analysis of current rotor blade production work procedures and technologies, followed by the assessment of potential for automation. Promising results will be thoroughly investigated and simulated. The conclusion of the project will see demonstrators created for the respective process steps, along with the presentation of the “BladeMaker blade”, fully designed and optimised for automated production.
The BladeMaker project will run until the end of September 2017. Funding of € 8 million was provided by the German Federal Ministry for the Environment, Nature Conservation and Reactor Safety.
Coincidentally, October 2012 also saw the arrival of the world’s longest rotor blade: an 80m XXL prototype manufactured by Danish company SSP Technology. A wind turbine using these rotor blades would attain a diameter of 171m and would be capable of higher levels of full-load hours than current generations. The testing facility at Fraunhofer IWES in Bremerhaven is currently the largest in the world and is being relied upon to provide statements on durability under the IEC 61400-23 standards, in a few months’ time. If the testing outcomes are satisfactory, series manufacture will begin and the giant rotor blades could be fitted onto new 7MW offshore turbines in South Korea before the end of 2013. The testing facility is the result of an €11 million investment, supported by the State of Bremen; the Federal Ministry for the Environment; and the European Union. It has been operating to full capacity since it was opened.