Offshore wind, tidal and wave energies represent an emerging — yet hitherto little exploited — alternative in the field of renewable energies.
IFPEN's main fields of activity in the wind power sector relate to four areas, the objective being to reduce the cost of wind power and create new markets:
- the development of floating offshore wind power technologies,
- the active control of wind turbine technology (offshore and onshore),
- the integrated simulation of the behavior of wind turbines in their environment,
- the optimization of operations and maintenance (O&M) thanks to digital technology.
IFPEN is also contributing to the development of a control strategy for efficient wave energy technology that can be used by industry.
Floaters for offshore wind turbines
A floater developed by IFPEN in partnership with SBM Offshore has now been dimensioned and will be tested off the French coast as part of a pre-commercial wind farm project from 2020.
« Our partnership with SBM Offshore led to the emergence of an innovative solution for a floating support for offshore wind turbines, with a number of associated advantages:
- light, compact and modular, it is also highly reliable thanks to the use of tried and tested components,
- investment costs are reduced due to its exceptional nacelle stability, reducing stresses and the mechanical fatigue of the components as a whole, lastly, it can be installed in shallow-water zones and does not require specific infrastructure to construct and deploy the turbines.
« This technology was chosen by EDF Energies Nouvelles for its Provence Grand Large pilot farm project, supported by Ademe. The objective is to demonstrate the technical and economic relevance of the solution. »
Timothée Perdrizet, Floating Wind Turbine project manager, IFPEN
Solutions based on the use of lidar
Working in partnership with Leosphere, IFPEN is developing solutions designed to use wind measurements provided by lidar sensors to improve energy production, increase operating life spans and reduce the costs of maintaining wind turbines. Two technological solutions have emerged from this partnership.
« Measurement data provided by lidar are raw; they do not provide a direct measurement of wind. In order to exploit the data, they need to be numerically processed in such a way as to yield an estimation of the observed wind.
- The first solution we focused on concerns the reconstruction of the wind field in real time at various distances upstream of the wind turbine, as well as a forecast of wind properties at rotor level, where the lidar is unable to take measurements. These functionalities have been integrated into WiSE WindField software, currently at the experimental validation stage, particularly within the context of the projet ANR SmartEole.
- The second component of our research relates to optimal wind turbine management: we are researching and developing innovative control strategies using the reconstructed wind measurement, in order to generate instructions relating to the most appropriate generator torque, blade orientation and nacelle direction, given the wind conditions approaching the rotor. These strategies, incorporated in the WiSE Control solution, protect the wind turbine from excessive wind turbulence (gusts, for example), thereby reducing the load and the mechanical fatigue of its structure.
For both these solutions, we are drawing on our expertise in the fields of signal processing, optimization and command control. Our objective is to propose WiSE WindField in the catalog of our partner Leosphere in 2019. »
Fabrice Guillemin, Wind Turbine Control project manager, IFPEN
Simulation of wind turbine behavior in its environment
IFPEN and its partner Principia developed DeepLines Wind™ software that simulates the dynamic behavior of floating offshore wind turbines, on the basis of the DeepLines™ solution dedicated to the dynamic analysis of seabed-surface links.
« DeepLines Wind™ has been marketed since 2015. Some of its features already existed in the original version, such as the calculation of the force of the waves and current on a floating body and the calculation of structural deformations. Alongside these, aerodynamic calculation capacities developed by IFPEN were incorporated to analyze the effects of wind on wind turbine blades, as were features associated with command control. Bringing these three types of physical analyses together makes it possible to perform combined mechanical simulations of all of the wind turbine’s components (blades, anchoring system, tower, floater) using the same software, an obvious advantage compared to the competition. The performance of this software was demonstrated in the IEA-Wind program’s OC4/OC5/OC6 and DANAERO projects and we are continuing to improve our models, as well as the aerodynamic libraries employed. In addition, we are using DeepLines Wind™ to design the floater for the Provence Grand Large project with our partner SBM Offshore. »
Pauline Bozonnet, project manager, IFPEN
Reducing wake effects between wind turbines on the same farm
In order to improve wind farm efficiency, IFPEN is drawing on its expertise to build the FarmShadow™ modeling tool, designed to help gain a better understanding of the wake effects generated by the presence of a wind turbine and their potential impact on the production of wind turbines located downstream. The wake developed behind a wind turbine leads to a decrease in wind speed, which in turn reduces the energy received by the next turbine. The loss of energy associated with this effect is typically between 10 and 20% on a wind farm compared to single wind turbines in isolation. Wake also leads to an increase in turbulence intensity, which in turn reinforces fatigue stresses on turbines and fixed or floating foundations located downstream.
FarmShadow™ is used in conjunction with optimization libraries. For farms in the design phase, FarmShadow™ allows to optimize the positioning of the various wind turbines relative to one another in order to maximize the energy produced. For existing farms, FarmShadow™ can be used to determine the optimal orientation of and the most suitable operating point for each turbine, in order to redirect wakes and limit their range. These actions make it possible to reduce aerodynamic interference between wind turbines, with the advantages of optimized production and reduced structural stresses.
Following DeepLines Wind™, on the market since 2015 and used to simulate all of a wind turbine’s components (see above), the FarmShadow™ tool allows to perform simulations at the farm scale and offers a broad range of services. It is based on the state of the art of wake models and is continuously improved by research conducted at IFPEN alongside partners such as Météo France (the French national weather service) or within the framework of the ANR Momenta project.
Control of wave energy conversion systems
Wave energy conversion systems are still at a very early stage of their development. Since 2017, IFPEN has been contributing to the ADEME S3 project aimed at significantly reducing the levelized cost of the energy associated with them, via a disruptive technological solution.
« We are participating in this project alongside SBM Offshore, with whom we are also developing a floater for offshore wind turbines, and the École centrale de Nantes engineering school. The objective? To produce and test in real operating conditions an innovative wave energy conversion demonstrator, based on a system designed by SBM Offshore. Its specific characteristics? The system uses electroactive polymers that change shape under the action of the swell, thereby converting wave energy directly into electricity.
We are responsible for the development of short-term prediction strategies concerning wall deformation induced by the swell, which will make it possible to actively control the machine and increase its electricity production capacity. With this project, we are seeking to validate a disruptive technological solution to improve the profitability of wave energy and foster its widespread use. »
Paolino Tona, project manager, IFPEN