The Nénuphar Solution
Most onshore and offshore wind turbines are fixed base horizontal axis wind turbines.
Nénuphar is developing an innovation that is a definitive breakthrough in existing technologies: a floating vertical axis contrarotative wind turbine. Those wind turbines fit the marine environment best and produce an energy that is 30% cheaper than that of horizontal axis turbines.
The development of this very innovative technology is justified by significant breakthroughs on several criteria such as output improvement and reduction of the constraints on the floater. It is possible to list the main indicators of the technical development as follows:
- The vertical axis contrarotative technology allows to outdo usual wind turbines performances thanks to an aerodynamic effect that increases the rotors performance, and to an instable wake that allows wind speed recovery on very short distances.
- The floater technology remains expensive for usual wind turbines because usual rotors have a low tolerance to the tilt and the strong heeling moment generated by the wind. The Nénuphar technology not only is more tolerant to the tilt, but also it quasi divides the heeling moment by 2 with a lower gravity center and the cancellation of the thrusts transversal components by the contrarotative structure.
The floating vertical axis contrarotative wind turbine enjoys several assets
- Power coefficient (wind-electricity conversion output) over 50% (against 43-45% for most current wind turbines)
- Wind speed recovery on short distances compatible with power density of about 5 MWe/km² to eliminate wake losses that represent 10-12% of the Annual Energy Production in traditional wind farms,
- Reduction of the heeling moment by at least 40% in comparison with traditional wind turbines with equivalent power coefficient.