New Test Bench for XXL Rotor Blades in Germany

Fraunhofer IWES received funding to the tune of around € 12 million for the `Future Concept Operational Stability Rotor Blades Phase II` project. The scientists develop and test out new methods for the evaluation of modern rotor blades measuring up to 115 meters in length. To this end, a new test bench is set to be constructed in Bremerhaven as of the end of 2019. It encompasses a very large test bed for full-scale blade testing and benches for segment and component tests. The predecessor project investigated the viability of new test procedures and tested them out in small-scale test runs; the second phase will now see them employed on a larger scale.

Actual developments have now exceeded the specialists’ expectations: When Fraunhofer IWES opened the first rotor blade testing hall with its 70-meter test bed back in 2009, the maximum length of a rotor blade was just 62.5 meters. This was joined by a second hall in 2011, allowing testing of blades measuring up to 90 meters. However, blades measuring 100 meters are now already entering their respective testing phases, and these cannot currently be tested at Fraunhofer IWES. But this is going to change now as the new test bench is expected to start operation in 2021.

The core of the planned test bench will be a new test block measuring 11x11 meters and with the option of being extended to suit higher blade lengths in future if and when required. Moreover, the test bench will comprise the possibility to offer component and segment testing – which is a novelty for the wind industry.

"Large independent test facilities are a major enabler for our upcoming developments of large offshore turbines. New concepts such as component testing and segment testing of blades are extremely interesting for us," explains Flemming Kløcker Grove, Senior Project Manager at MHI Vestas Offshore Wind.

"It’s not just about testing longer blades – we also want to test more intelligently and expand our position as a leading institute for rotor blade tests," explained Steffen Czichon, Head of Fraunhofer´s Department for Rotor Blades.

The aim of the ´Future Concept Operational Stability Rotor Blades Phase II´ project is to ensure that experimental testing of very long rotor blades remains economically viable for manufacturers. New testing procedures for the investigation of segments and components will offer a better understanding of critical areas and thus increase the informative value of the tests considerably. This information can be employed to design rotor blades even more precisely in the future, thereby saving on both weight and costs.

Breakdown of funding for the “Future Concept Operational Stability Rotor Blades Phase II” project:

• Hall construction: German Federal Ministry of Education and Research (BMBF) and the State of Bremen/ERDF, € 3.4 million altogether
• Test bench construction: German Federal Ministry for Economic Affairs and Energy (BMWi), €8 million
• Method development work packet: State of Bremen/ERDF: € 253,000