Mechanical Augmentation Channel Design for Turbine Current Generators

We present the design and analysis of augmentation channels to increase the efficiency of shrouded marine current turbines in conditions of low intensity flows. These turbines are part of a prototype of a floating device composed of wind and marine current generators for generating renewable energy. It intends to exploit renewable energy resources in an integrated manner using wind and current turbines in offshore plants optimizing the economic investment.García Moreno, E.; Pizá Fernández, R.; Benavides, X.; Quiles Cucarella, E.; Correcher Salvador, A.; Morant Anglada, FJ. (2014). Mechanical Augmentation Channel Design for Turbine Current Generators. Advances in Mechanical Engineering. 2014:1-12. doi:10.1155/2014/650131S1122014Namik, H., & Stol, K. (2010). Individual blade pitch control of floating offshore wind turbines. Wind Energy, 13(1), 74-85. doi:10.1002/we.332Lackner, M. A., & Rotea, M. A. (2011). Structural control of floating wind turbines. Mechatronics, 21(4), 704-719. doi:10.1016/j.mechatronics.2010.11.007Betti, G., Farina, M., Guagliardi, G. A., Marzorati, A., & Scattolini, R. (2014). Development of a Control-Oriented Model of Floating Wind Turbines. IEEE Transactions on Control Systems Technology, 22(1), 69-82. doi:10.1109/tcst.2013.2242073Gorban’, A. N., Gorlov, A. M., & Silantyev, V. M. (2001). Limits of the Turbine Efficiency for Free Fluid Flow. Journal of Energy Resources Technology, 123(4), 311-317. doi:10.1115/1.1414137Radkey R. L., and Hibbs B. D. “Definition of cost effective river turbine designs,” 1981 no. AV-FR-81/595 (DE82010972), U.S. Department of Energy, Pasadena, Calif, USA.Gilbert, B. L., & Foreman, K. M. (1983). Experiments With a Diffuser-Augmented Model Wind Turbine. Journal of Energy Resources Technology, 105(1), 46-53. doi:10.1115/1.3230875Rosenbrock, H. H. (1960). An Automatic Method for Finding the Greatest or Least Value of a Function. The Computer Journal, 3(3), 175-184. doi:10.1093/comjnl/3.3.175Gaden, D. L. F., & Bibeau, E. L. (2010). A numerical investigation into the effect of diffusers on the performance of hydro kinetic turbines using a validated momentum source turbine model. Renewable Energy, 35(6), 1152-1158. doi:10.1016/j.renene.2009.11.023Mikkelsen, R., Sørensen, J. N., & Shen, W. Z. (2001). Modelling and analysis of the flow field around a coned rotor. Wind Energy, 4(3), 121-135. doi:10.1002/we.50Cao, Y., & Yu, Z. (2005). Numerical simulation of turbulent flow around helicopter ducted tail rotor. Aerospace Science and Technology, 9(4), 300-306. doi:10.1016/j.ast.2005.01.006Ponta, F. L., & Jacovkis, P. M. (2008). Marine-current power generation by diffuser-augmented floating hydro-turbines. Renewable Energy, 33(4), 665-673. doi:10.1016/j.renene.2007.04.008Khan, M. J., Iqbal, M. T., & Quaicoe, J. E. (2008). River current energy conversion systems: Progress, prospects and challenges. Renewable and Sustainable Energy Reviews, 12(8), 2177-2193. doi:10.1016/j.rser.2007.04.01

Ocean Energy in Belgium - 2019

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Efficient preliminary floating offshore wind turbine design and testing methodologies and application to a concrete spar design

The current key challenge in the floating offshore wind turbine industry and research is on designing economic floating systems that can compete with fixed-bottom offshore turbines in terms of levelized cost of energy. The preliminary platform design, as well as early experimental design assessments, are critical elements in the overall design process. In this contribution, a brief review of current floating offshore wind turbine platform pre-design and scaled testing methodologies is provided, with a focus on their ability to accommodate the coupled dynamic behaviour of floating offshore wind systems. The exemplary design and testing methodology for a monolithic concrete spar platform as performed within the European KIC AFOSP project is presented. Results from the experimental tests compared to numerical simulations are presented and analysed and show very good agreement for relevant basic dynamic platform properties. Extreme and fatigue loads and cost analysis of the AFOSP system confirm the viability of the presented design process. In summary, the exemplary application of the reduced design and testing methodology for AFOSP confirms that it represents a viable procedure during pre-design of floating offshore wind turbine platforms.Peer ReviewedPostprint (author’s final draft

A regressive machine-learning approach to the non-linear complex FAST model for hybrid floating offshore wind turbines with integrated oscillating water columns

Offshore wind energy is getting increasing attention as a clean alternative to the currently scarce fossil fuels mainly used in Europe's electricity supply. The further development and implementation of this kind of technology will help fighting global warming, allowing a more sustainable and decarbonized power generation. In this sense, the integration of Floating Offshore Wind Turbines (FOWTs) with Oscillating Water Columns (OWCs) devices arise as a promising solution for hybrid renewable energy production. In these systems, OWC modules are employed not only for wave energy generation but also for FOWTs stabilization and cost-efficiency. Nevertheless, analyzing and understanding the aero-hydro-servo-elastic floating structure control performance composes an intricate and challenging task. Even more, given the dynamical complexity increase that involves the incorporation of OWCs within the FOWT platform. In this regard, although some time and frequency domain models have been developed, they are complex, computationally inefficient and not suitable for neither real-time nor feedback control. In this context, this work presents a novel control-oriented regressive model for hybrid FOWT-OWCs platforms. The main objective is to take advantage of the predictive and forecasting capabilities of the deep-layered artificial neural networks (ANNs), jointly with their computational simplicity, to develop a feasible control-oriented and lightweight model compared to the aforementioned complex dynamical models. In order to achieve this objective, a deep-layered ANN model has been designed and trained to match the hybrid platform's structural performance. Then, the obtained scheme has been benchmarked against standard Multisurf-Wamit-FAST 5MW FOWT output data for different challenging scenarios in order to validate the model. The results demonstrate the adequate performance and accuracy of the proposed ANN control-oriented model, providing a great alternative for complex non-linear models traditionally used and allowing the implementation of advanced control schemes in a computationally convenient, straightforward, and easy way.This work was supported in part by the Basque Government through project IT1555-22 and through the projects PID2021-123543OB-C21 and PID2021-123543OB-C22 (MCIN/AEI/10.13039/501100011033/FEDER, UE). The authors would also like to thank the UPV/EHU for the financial support through the María Zambrano grant MAZAM22/15 and Margarita Salas grant MARSA22/09 (UPV-EHU/MIU/Next Generation, EU) and through grant PIF20/299 (UPV/EHU)

Fuzzy logic control of an artificial neural network-based floating offshore wind turbine model integrated with four oscillating water columns

Renewable energy induced by wind and wave sources is playing an indispensable role in electricity production. The innovative hybrid renewable offshore platform concept, which combines Floating Offshore Wind Turbines (FOWTs) with Oscillating Water Columns (OWCs), has proven to be a promising solution to harvest clean energy. The hybrid platform can increase the total energy absorption, reduce the unwanted dynamic response of the platform, mitigate the load in critical situations, and improve the system's cost efficiency. However, the nonlinear dynamical behavior of the hybrid offshore wind system presents an opportunity for stabilization via challenging control applications. Wind and wave loads lead to stress on the FOWT tower structure, increasing the risk of damage and failure, and raising maintenance costs while lowering its performance and lifespan. Moreover, the dynamics of the tower and the platform are extremely sensitive to wind speed and wave elevation, which causes substantial destabilization in extreme conditions, particularly to the tower top displacement and the platform pitch angle. Therefore, this article focuses on two main novel targets: (i) regressive modeling of the hybrid aero-hydro-servo-elastic-mooring coupled numerical system and (ii) an ad-hoc fuzzy-based control implementation for the stabilization of the platform. In order to analyze the performance of the hybrid FOWT-OWCs, this article first employs computational Machine Learning (ML) techniques, i.e., Artificial Neural Networks (ANNs), to match the behavior of the detailed FOWT-OWCs numerical model. Then, a Fuzzy Logic Control (FLC) is developed and applied to establish a structural controller mitigating the undesired structural vibrations. Both modeling and control schemes are successfully implemented, showing a superior performance compared to the FOWT system without OWCs. Experimental results demonstrate that the proposed ANN-based modeling is a promising alternative to other intricate nonlinear NREL 5 MW FOWT dynamical models. Meanwhile, the proposed FLC improves the platform's dynamic behavior, increasing its stability under a wide range of wind and wave conditions.This work was supported in part by the Basque Government through project IT1555-22 and through the projects RTI2018-094902-B-C22 (MCIU/AEI/FEDER, UE), PID2021-123543OB-C21 and C22 funded by MCIN/AEI/10.13039/501100011033. The authors would also like to thank the UPV/EHU for the financial support through the Maria Zambrano grant MAZAM22/15 funded by the European Union-Next Generation EU and through grant PIF20/299

Potential for Solar Energy in Food Manufacturing, Distribution and Retail

The overall aim of the study was to assess the potential for increasing the use of solar energy in the food sector. For comparative purposes the study also included an assessment of the benefits that could arise from the use of other renewable energy sources, and the potential for more effective use of energy in food retail and distribution. Specific objectives were to: i) establish the current state of the art in relevant available solar technology; ii) identify the barriers for the adoption of solar technology; iii) assess the potential for solar energy capture; iv) appraise the potential of alternative relevant technologies for providing renewable energy; v) assess the benefits from energy saving technologies; vi) compare the alternative strategies for the next 5-10 years and vii) Consider the merits of specific research programmes on solar energy and energy conservation in the food sector. To obtain the views of the main stakeholders in the relevant food and energy sectors on the opportunities and barriers to the adoption of solar energy and other renewable energy technologies by the food industry, personal interviews and structured questionnaires tailored to the main stakeholders (supermarkets, consultants for supermarket design; energy and equipment suppliers) were used. The main findings from the questionnaires and interviews are: - Key personnel in supermarkets and engineers involved in the design of supermarkets are aware of the potential contribution of renewable energy technologies and other energy conservation measures to energy conservation and environmental impact reduction in the food industry. A number of supermarket chains have implemented such technologies at pilot scale to gain operating experience, and more importantly, for marketing reasons, to gain competitive advantage through a green image. - From installations to date in the UK the most notable are a 600 kW wind turbine at a Sainsbury's distribution centre in East Kilbride and a 60 kWp photovoltaic array at a Tesco store in Swansea. - The main barrier to the application of renewable energy technologies in the food sector is the capital cost. Even though significant progress has been made towards the improvement of the energy conversion efficiencies of photovoltaic technologies (PVs) and reduction in their cost, payback periods are still far too long, for them to become attractive to the food industry. - Wind energy can be more attractive than PVs in areas of high wind speed. Apart from relatively high cost, the main barrier to the wide application of wind turbines for local power generation is planning restrictions. This technology is more attractive for application in food distribution centres that are normally located outside build-up areas where planning restrictions can be less severe than in urban areas. In these applications it is likely that preference will be for large wind turbines of more than 1.0 MW power generation capacity as the cost of generation per unit power reduces with the size of the turbine

Long-term research challenges in wind energy – a research agenda by the European Academy of Wind Energy

The European Academy of Wind Energy (eawe), representing universities and institutes with a significant wind energy programme in 14 countries, has discussed the long-term research challenges in wind energy. In contrast to research agendas addressing short- to medium-term research activities, this eawe document takes a longer-term perspective, addressing the scientific knowledge base that is required to develop wind energy beyond the applications of today and tomorrow. In other words, this long-term research agenda is driven by problems and curiosity, addressing basic research and fundamental knowledge in 11 research areas, ranging from physics and design to environmental and societal aspects. Because of the very nature of this initiative, this document does not intend to be permanent or complete. It shows the vision of the experts of the eawe, but other views may be possible. We sincerely hope that it will spur an even more intensive discussion worldwide within the wind energy community