In a significant leap towards enhancing offshore wind energy, a groundbreaking turbine technology is poised to undergo testing in Norway. The 19-meter (62-foot) 30-kilowatt contra-rotating vertical-axis turbine represents a prototype of a design capable of reaching unprecedented sizes and power levels. While traditional wind turbines feature a propeller-on-a-stick design, this new technology offers an alternative that could potentially cut the costs of offshore wind energy production in half.
Current wind turbine designs, when scaled up for offshore use, present engineering challenges. These challenges stem from the concentration of heavy components at the top of the structure, leading to increased complexity and expenses in constructing and maintaining floating platforms to withstand turbulent ocean conditions.
The contra-rotating vertical-axis turbine, developed by World Wide Wind (WWW), presents an innovative solution by placing the heavy generator components at the bottom of the structure, submerged underwater beneath the floating pontoon. This added weight at the bottom provides stability, eliminating the need for complex counterbalancing systems. The generator’s rotor and stator are connected to two vertical-axis turbines, each equipped with three blades set at a 45-degree angle from the central tower shaft.
One of the turbines rotates in one direction, while the other, mounted on a pole within the first, rotates in the opposite direction. The fixed blades harness torque from the wind over most of their rotation, ensuring that the turbine remains efficient and effective regardless of the wind’s direction.
By skillfully managing the generator’s resistance, the speed of the turbine can be controlled at a microsecond level, enabling passive adjustment to the optimal angle according to the wind direction. This dynamic feature ensures that the two turbines spin in opposite directions, effectively doubling the rotor’s rotational speed within the stator. The result is a potential doubling of power generation or a reduction in generator costs by half, thanks to the unique design.
Notably, this innovative technology’s structure neutralizes the torque induced by the wind, while the conical rotor design minimizes blade tip speed and wake turbulence. This advantageous feature allows the turbines to be positioned closer together in a wind farm, increasing energy production and reducing the need for extensive connection cabling.
World Wide Wind envisions scaling these turbines to towering heights of up to 400 meters (1,312 feet), with a single tower capable of harvesting an astonishing 40 megawatts of power. This output is nearly double the capacity of the world’s largest conventional wind turbines. Moreover, the technology holds the potential to significantly reduce the Levelized Cost of Energy (LCoE) for offshore wind to less than $50 per megawatt-hour, less than half the cost targeted by horizontal-axis towers by 2027.
The testing of a small-scale 19-meter prototype in collaboration with AF Gruppen, one of Norway’s prominent industrial construction groups, is the first step in realizing the potential of this revolutionary design. While a precise testing schedule has not been disclosed, the company is planning to conduct trials of a larger 1.5-megawatt pilot in early 2025. With the ambition to launch a commercial 24-megawatt turbine before 2030, this technology has the potential to become the world’s largest offshore turbine, revolutionizing offshore wind energy and making a substantial impact on the global energy landscape.
The development of such massive wind turbines is eagerly awaited, as they hold the potential to accelerate the world’s transition towards renewable energy sources.
By Impact Lab