Generating electricity in areas with little wind is often difficult. Researchers at the Fraunhofer Institute for Applied Polymer Research IAP, together with the BBF Group, have developed a new lightweight rotor that can run even in weak wind conditions. The small wind turbine starts rotating at only 2.7 metres per second, compared to the usual four metres per second for similar systems. This makes it ideal for homes, small businesses, and off-grid sites aiming to use renewable energy more efficiently.
Fraunhofer’s design team approached the project holistically, improving both shape and production. The new turbine reaches 450 revolutions per minute and produces 2.5 kilowatts at 10 metres per second wind speed. This is 83% more powerful than typical systems and achieves an impressive 53% efficiency—close to the theoretical maximum of 59%.
Each rotor blade consists of two lightweight fibre composite shells instead of a heavy foam core. This hollow structure cuts total weight by up to 35%. As a result, the turbine reacts quickly to light winds while staying stable in stronger gusts.
To ensure precision, the team used a large-format 3D printer to create custom moulds. They also applied Automated Fibre Placement (AFP) to position the fibre strips with minimal overlap and waste. This automated process guarantees consistent quality and smaller, lighter parts.
The composite layers were carefully arranged so that the blades can flex under strong winds. When the pressure rises, they naturally turn out of the wind. This flexible response reduces speed and prevents damage, removing the need for complex mechanical controls.
Five prototypes are now being tested by the BBF Group at different sites. The results will help determine the best installation height and location. The next development step will replace multi-material composites with monomaterial lightweight structures, making them easier to recycle. This innovation supports circular material design and contributes to more sustainable wind energy systems.
Source & image: Fraunhofer Institute