China wants to counter shortage of raw materials with own cultivation

Balsa is a very light, easy-to-machine type of wood with a very low density, which is why it is of great importance worldwide as a core material of fibre composites in sandwich construction, for example in boat, sail and small aircraft construction. And it is also suitable for some types of wind turbine rotor blades.

While China now builds the most wind turbines in the world and is expanding wind energy at a rapid pace, suppliers are having more and more problems finding enough balsa wood. Balsa trees grow mainly in Central and South America and in the tropics. And while China's wind industry, which is worth billions, can source almost all materials domestically, the country is dependent on imports for balsa wood.

The Chinese now want to change that, as BNN Bloomberg reports. In the tropical climate of China's southern Yunnan province, scientists have begun planting their own balsa plantations to reduce dependence on imports.

“Given the carbon peaking and neutrality targets, clean energy became a very important issue,” says Zou Shouqing, a retired professor at Xishuangbanna Tropical Botanical Garden of Chinese Academy of Sciences, according to Bloomberg. “So the country needs balsa wood.” About four square kilometres of balsa wood were planted in Xishuangbanna in the past two years. More planting is planned, which could supply about 10% of the national demand. But as it takes at least four years for a tree to be ready for harvesting, China's first own balsa wood cannot be harvested before 2024. Planting “needs to continue to develop, or it still won’t be enough," says Zou.

But even then, economic success is not guaranteed, because it is unclear whether the home-grown product will be able to compete in quality with timber from abroad. In Xishuangbanna, temperatures are lower and there is less rainfall than in important supplier countries like Ecuador and Papua New Guinea, which can lead to a higher density of the wood. There are also high transport costs from the plantations to the production facilities in China.

In any case, there is now an artificial alternative: polyethylene terephthalate (PET). The light, robust plastic material has been on the rise in recent years and threatens to overtake its wooden competitor in the future. Analysis firm Wood Mackenzie estimates that PET will overtake balsa wood as the most important core material for rotor blades and account for about 60 % of the global share by 2025.

On the other hand, the two composite manufacturers Schweiter and Gurit, who work with the materials, do not agree on where the future lies: While Schweiter continues to rely on balsa wood, Gurit is building on PET. Anyway Schweiter Group CEO Heinz O. Baumgartner told the NZZ last year: "Balsa has a future."