In China, bamboo is used for lots of things, from houses to both paper and clothes. So why not also use it for wind turbine blades? Risø DTU is helping the Chinese forestry commission to examine the possibilities of the material. Risø has been working for a number of years with different natural fibres for wind turbine blades, so when the International Centre for Bamboo and Rattan (ICBR) contacted the Materials Research Department for assistance in connection with a scientific assessment of bamboo, it immediately caught the interest of Head of Programme Povl Brøndsted. And he was quickly convinced that bamboo offers considerable potential for both the Asian and, in particular, the Chinese markets.
Concept expected to be ready in two years
Risø DTU and ICBR have now signed a partnership agreement under which Risø will test and certify the bamboo material for subsequent introduction to different manufacturers while the Chinese institute will develop the technology required to manufacture the blades.
“We have agreed to openly publish all results once a year. We do not want to reserve our knowledge for one particular company,” says Povl Brøndsted, who expects to receive subsidies for the project from different foundations this autumn, and adds: “And we hope to have made a finished concept blade within the next couple of years, or perhaps to have sold the idea to one of the large players in the market.”
A sustainable material
Bamboo is a fast-growing plant which can grow to up to 200 mm in diameter and a height of 40 metres. The plants grow faster than trees, which makes them more sustainable. Furthermore, they grow in areas where labour is cheap and where unemployment is high – and where there is a considerable need for local energy supplies, for example from wind turbines.
Bamboo is also a cheap, light and strong material. A bamboo composite is much stronger than, for example, birch. It may not even be necessary to reinforce the bamboo composite with glass fibre for 20-30 metre blades.
The blades will initially be made from bamboo shreds glued together using epoxy, but Povl Brøndsted hopes in time to be able to replace the synthetic epoxy material with a bio-based adhesive. The manufacturing process will also need to be further developed, one of the problems being that bamboo absorbs a lot of water.
Bamboo does it all
Bamboo has a virtually limitless range of applications. From paper to furniture and flooring, indeed you can make an entire house from bamboo, something which the Chinese have been doing for thousands of years. The Chinese poet and calligrapher Su Dongpo, who lived in the 11th century, said: “I prefer live in a bamboo house, even without eating
meat”.
These days, many designer items and clothes made from bamboo are being introduced to the market. Povl Brøndsted regularly holds lectures about this highly applicable material, for example for Danish designers, with whom he enjoys good working relationships. He has no doubt that bamboo is on the rise.
At the coming workshop on wind energy in Nepal in November, bamboo blades for wind turbines are on the agenda. Read the programme for the International Workshop on Natural and Low–cost Materials in Wind Energy Technologies.
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