Periodic Reporting for period 1 - FLOATECH (Optimization of floating wind turbines using innovative control techniques and fully coupled open source engineering tool)
Reporting period: 2021-01-01 to 2022-06-30
Wind is one of the main sources of renewable energy that contributes to the EU energy mix. Its exploitation is pivotal to meet future environmental and energy policy goals. Due to the limitations of available installation sites onshore, offshore wind is becoming crucial to ensure the further growth of the sector. In this scenario, exploiting the vast wind resources in deeper waters using floating wind farms and developing the required technology will enhance EU’s economy and contribute to achieve its green energy goals. The FLOATECH project aims to advance the technical maturity and cost competitiveness of floating offshore wind energy. This will be achieved with two types of actions. First, a fully-coupled, aero-hydro- servo-elastic design and simulation environment (named QBlade-Ocean) will be developed (A1). The more advanced modelling approaches will lead to a reduction of the uncertainties in the design process and subsequently to more efficient, reliable and cost-effective floating wind turbines (WTs). Additionally, two innovative control techniques will be introduced (A2) (active wave-based feed-forward and active wake mixing strategies). Both will lead to an increase of the energy yield of floating wind farms and in the case of the wave-based control, fatigue loads could be reduced substantially.
Work Package 1 (High order open-source aero-hydro-servo-elastic simulation tool) (WP1) focuses on the development of the open-source simulation tool (ST) QBlade-Ocean (QB). More specifically, the simulation software has been expanded by the capability to model offshore WTs (floating and bottom fixed). Additionally, a higher order aerodynamic solver (particles) was implemented into the software tool and the software NEMOH was extended with the capability to generate quadratic transfer functions. An interface between QB and NEMOH was created. Finally, a project partner training was carried out to convey all the knowledge needed to run simulations in QB to its fullest capability.
The objective of WP2 (Quantification of uncertainty reduction gained through QBlade-Ocean) is first, to validate the new capabilities of QB and second, to quantify the achieved reduction of uncertainties. The former task has been carried out almost completely. Thereby, differing floater concepts are simulated in QB and compared to experimental results and/or state-of-the-art (SOTA) STs. The validation is performed on a variety of load cases. The second task will begin after the submission of this summary; however, some preliminary work has been conducted (the set of design load cases was defined).
WP3 (Feed forward wave-based control) focuses on the development of the novel feed forward wave-based controller to minimize oscillations and thus fatigue loads over the lifetime of a WT (A2). The necessary interface of the controller with QB was accomplished to feed future wave load information into the controller. This allows the prediction of wave forces that will act on the floater and thus, floater motion. As the wave prediction will be tested in experiments in reporting period 2, preparatory steps were taken for the full integration of the controller into a wave tank setup. One of them being a campaign in which wave data was collected with several wave gauges that will serve as a database used for validation. Furthermore, since the technology will partly be tested in realistic conditions near the shore of France on the Floatgen turbine, a radar system capturing the wave elevation information is already installed on the platform.
The second innovative control method in A2 is the application of wake mixing control strategies on floating offshore WTs in WP4 (Active wake mixing in floating wind turbine farms). To understand how and at which frequency the wake can be excited most efficiently, an investigation to better understand the physical phenomenon of the wake breakdown has been undertaken. Additionally, the effects of platform motion and atmospheric conditions on the breakdown were investigated. Based on these results, a design optimization of floating platforms for wind turbines is currently ongoing. The design objective is to find a configuration the favors the control strategy by maximizing the wake recovery with minimal control inputs
WP5 (LCOE and market value evaluation of proposed technologies and scale up) starts in reporting period 2.
In WP6 (Dissemination, Communication and Exploitation), several communication efforts towards the broader public were made, including the set up of a project website, LinkedIn and Twitter profiles. Interviews on radio broadcasts and publications in public oriented journals were also produced. Dissemination actions were carried out through participation at two WindEurope events, one including the co-organization of a side event. Aside from the above, the project was presented to peers through presentations at multiple scientific conferences.
WP7 (Management of the project) focused on the project management. Hence, a management structure is put into place, regularly occurring meetings on different levels are organized, the decision-making process is promoted when necessary, a quality management plan was implemented into the project and a cloud service was set up. Moreover, the project management team acts as an intermediary with the EC and is responsible of the periodic and continuous reporting duties.
The objective of WP2 (Quantification of uncertainty reduction gained through QBlade-Ocean) is first, to validate the new capabilities of QB and second, to quantify the achieved reduction of uncertainties. The former task has been carried out almost completely. Thereby, differing floater concepts are simulated in QB and compared to experimental results and/or state-of-the-art (SOTA) STs. The validation is performed on a variety of load cases. The second task will begin after the submission of this summary; however, some preliminary work has been conducted (the set of design load cases was defined).
WP3 (Feed forward wave-based control) focuses on the development of the novel feed forward wave-based controller to minimize oscillations and thus fatigue loads over the lifetime of a WT (A2). The necessary interface of the controller with QB was accomplished to feed future wave load information into the controller. This allows the prediction of wave forces that will act on the floater and thus, floater motion. As the wave prediction will be tested in experiments in reporting period 2, preparatory steps were taken for the full integration of the controller into a wave tank setup. One of them being a campaign in which wave data was collected with several wave gauges that will serve as a database used for validation. Furthermore, since the technology will partly be tested in realistic conditions near the shore of France on the Floatgen turbine, a radar system capturing the wave elevation information is already installed on the platform.
The second innovative control method in A2 is the application of wake mixing control strategies on floating offshore WTs in WP4 (Active wake mixing in floating wind turbine farms). To understand how and at which frequency the wake can be excited most efficiently, an investigation to better understand the physical phenomenon of the wake breakdown has been undertaken. Additionally, the effects of platform motion and atmospheric conditions on the breakdown were investigated. Based on these results, a design optimization of floating platforms for wind turbines is currently ongoing. The design objective is to find a configuration the favors the control strategy by maximizing the wake recovery with minimal control inputs
WP5 (LCOE and market value evaluation of proposed technologies and scale up) starts in reporting period 2.
In WP6 (Dissemination, Communication and Exploitation), several communication efforts towards the broader public were made, including the set up of a project website, LinkedIn and Twitter profiles. Interviews on radio broadcasts and publications in public oriented journals were also produced. Dissemination actions were carried out through participation at two WindEurope events, one including the co-organization of a side event. Aside from the above, the project was presented to peers through presentations at multiple scientific conferences.
WP7 (Management of the project) focused on the project management. Hence, a management structure is put into place, regularly occurring meetings on different levels are organized, the decision-making process is promoted when necessary, a quality management plan was implemented into the project and a cloud service was set up. Moreover, the project management team acts as an intermediary with the EC and is responsible of the periodic and continuous reporting duties.
Both of the first two actions surpass the current SOTA in the simulation (A1) and control (A2) of floating offshore WTs. Focusing on A1 first, QB already matches the SOTA. In some cases, it even surpasses it due to the capability of combining a wide variety of approaches to model hydrodynamic forces with a medium-fidelity, lifting-line based aerodynamic solver and a non-linear structural solver. It is expected to surpass the SOTA further by the coupling of QB to the open-source software HOS-Ocean. When completed, QB will be the only wind turbine ST capable of simulating loads caused by higher-order spectral waves. The impact of such an accurate ST could substantially influence the way how the floating WT are constructed by reducing the necessary safety margins.
A2 comprises two control strategies that both aim to surpass the current SOTA due to innovative solutions. Both technologies are under development and the main results will be analyzed in much more detail in the remainder of this project. The expected results can however already be mentioned. The active wave-based control allows damping of the wave-excited oscillations without causing considerable fatigue loads over the life-cycle of the turbine. Thus, CAPEX could be reduced as components may be designed more economically and turbines could be operated in more efficient conditions. The second control strategy uses the innovative pulse and helix concepts to apply wake mixing. Both concepts excite the wake of a turbine and thereby accelerate the breakdown of it. This leads to a quicker recovery of the wake velocity, allowing a downwind turbine to generate more power. Applying this concept to floating WTs may increase its effectiveness, since the additional degrees of freedom of the floating foundation could increase the positive effect of the wake mixing concept. The potential impact would be a more effective operation of wind parks, due to the increase of the capacity factor of downwind turbines.
A2 comprises two control strategies that both aim to surpass the current SOTA due to innovative solutions. Both technologies are under development and the main results will be analyzed in much more detail in the remainder of this project. The expected results can however already be mentioned. The active wave-based control allows damping of the wave-excited oscillations without causing considerable fatigue loads over the life-cycle of the turbine. Thus, CAPEX could be reduced as components may be designed more economically and turbines could be operated in more efficient conditions. The second control strategy uses the innovative pulse and helix concepts to apply wake mixing. Both concepts excite the wake of a turbine and thereby accelerate the breakdown of it. This leads to a quicker recovery of the wake velocity, allowing a downwind turbine to generate more power. Applying this concept to floating WTs may increase its effectiveness, since the additional degrees of freedom of the floating foundation could increase the positive effect of the wake mixing concept. The potential impact would be a more effective operation of wind parks, due to the increase of the capacity factor of downwind turbines.