Our Tech
Energy transition powered by wind
The growing demand for renewable energy solutions has driven significant interest in the development of efficient, reliable wind energy systems. Our Vertical Axis Wind Turbines (VAWTs) are particularly well-suited for urban, rural and offshore environments due to their ability to capture wind from any direction and their potential for integration closer to structures and treelines. However, current VAWT designs face challenges related to efficiency, start-up behaviour, and adaptability to turbulent wind conditions. Flag Turbines has developed a hybrid VAWT design that integrates the Darrieus and Savonius designs to create a system capable of addressing these challenges.
At Flag Turbines, our research and development journey spans over 5 years, 10 generations and more than 12,000 hours of field testing. In 2022, we finally arrived at our core patented technology called the ‘Cycloidal Turbine’.
Darrieus Wind Turbine
Named after French inventor Georges Darrieus, this design features curved, eggbeater-shaped blades. It is known for high efficiency but can be less stable and require external power to start.
Savonius Wind Turbine
This type consists of two or more scooped blades, resembling a “S” shape when viewed from above. It operates based on drag rather than lift, making it less efficient but more reliable at lower wind speeds and self-starting.
The core of the design
The Flag Turbines approach to a new Vertical Axis Wind Turbine (VAWT) is in combining the aerodynamic characteristics of the Darrieus turbine with the robust, low-speed performance of the Savonius turbine. Our iterative R&D processes aimed to address common limitations of existing VAWT designs by leveraging the complementary strengths of both turbines. The Darrieus turbine, known for its high efficiency in converting wind energy at higher speeds, often struggles with self-starting and performance in turbulent, low-wind environments. Conversely, the Savonius turbine excels in generating torque at low wind speeds and initiating rotation but suffers from lower overall efficiency at higher speeds.
At Flag Turbines, we have reduced the downsides of both tech’s and increased the existing benefits substantially.
Outcome
The Flag Turbines design demonstrates a significant improvement in start-up behaviour, with the Savonius component initiating rotation at lower wind speeds and providing the necessary torque for the Darrieus blades to achieve higher rotational speeds. This combination results in a more consistent energy output across a range of wind speeds, with our hybrid turbine outperforming both individual Darrieus and Savonius turbines in terms of energy capture efficiency. Our innovative patented ‘cycloidal’ design features a slow-rotating, automatic blade-pitching mechanism and a high-torque, axial flux direct-drive generator. This design maximises power while minimising turbulence-induced vibration and noise levels, making it suitable for deployment across multiple environments.
