Surrogate hydrodynamic modelling for wave energy system control co-design

The Jacket platform needs gas and diesel to run its turbines, and in the end, they produce catastrophic emissions annually. The environmental concerns regarding these platforms have forced us to utilize an alternative source of energy that is sustainable and clean. In this study 51 locations, are of interest where oil and gas activities are in progress at present in the shape of a jacket platform or pipelines. The significant wave height and wave period scatter diagram data are collected from the platforms in the South China Sea. The linear wave theory is used to find the wave power. The given time period is converted into an equivalent time period first before wave energy is determined. The study shows that location no. 20 is the ideal location to deploy the wave energy converter Pelamis P2 with a potential mean wave power of 6.61 kW/m A single unit of Pelamis P2 can produce on an average electricity output of 91.37 kW/m including, the losses and machine efficiencies, whereas a wave farm can generate an average output of 62 GWh/yr. The electricity supply of 70.3 % of the minimum and 14.1 % of the maximum energy demand, while using only wave energy converter. If hybrid wind and wave energy system is used, then energy production will increase. The results show that the wave farm could also reduce the use of natural gas up to 17.6E06 m3/year, avoiding the emission of 12000 tonnes of CO and 54000 tonnes of NOx annually, and can save up to RM 20 billion annually with the reduction of natural gas emissions.

WECs microarray effect on the coupled dynamic response and power performance of a floating combined wind and wave energy system

Wave energy conversion and hydrodynamics modelling technologies: A review

Greening seaports: Evaluating impacts and policies for renewable energy systems

Achieving economic feasibility in wave energy conversion relies on the development of efficient and reliable control strategies, which require accurate control-oriented models of wave energy systems. However, deriving such models from first-principles-based hydrodynamic approaches can be challenging, as linearisation and small-motion assumptions often lead to discrepancies between theoretical predictions and real-world behaviour. Recognising these limitations, this paper presents a frequency-domain system identification approach applied to a multiple-degree-of-freedom wave energy converter, SWINGO. Experimental tests on a scaled prototype were conducted in a wave basin to obtain system response data under different operating conditions. The identification approach captures the coupled dynamics between the floater and gyropendulum, improving upon boundary-element-method-based models. The identified best linear approximation models are validated across multiple sea states, demonstrating their effectiveness in characterising the system response. Validation results are analysed in terms of normalised mean average percentage error, confirming the approach suitability for control design.

This paper presents a practical design of a wave energy converter (WEC). The WEC is based on an innovative mechanical device power take-off (PTO) which can convert wave energy into electric energy by using a floating buoy. By using cable and pulley mechanism, the WEC can work in high efficiency by capturing wave energy in both surge and heave mode and converting the bidirectional motion of ocean waves into one-way rotation of an electric generator. First, the configuration is presented to describe working principle of the system. Then, the hydrodynamic forces are analyzed in the time domain. Moreover, the coupled mechanical and hydrodynamic model are simulated in Matlab/Simulink to investigate the performance of the proposed design. Finally, simulation results indicate that the proposed WEC can absorb wave energy in high efficiency and can be applied in the realistic condition.

Renewable energy resources such as offshore wind and wave energy are environmentally friendly and omnipresent. A hybrid offshore wind-wave energy system produces a more sustainable form of energy that is not only eco-friendly but also economical and efficient as compared to use of individual resources. The objective of this paper is to give a detailed review of co-generation technologies for hybrid offshore wind and wave energy. The proposed area of this review paper is based on the power conversions techniques, response coupling, control schemes for co-generation and complimentary generation, and colocation and integrated conversion systems. This paper aims to offer a systematic review to cover recent research and development of novel hybrid offshore wind-wave energy (HOWWE) systems. The current hybrid wind-wave energy structures lack efficiency due to their design and AC-DC-AC power conversion that need to be improved by applying an advanced control strategy. Thus, using different power conversion techniques and control system methodologies, the HOWWE structure can be improved and will be transferrable to the other hybrid models such as hybrid solar and wind energy. The state-of-the-art HOWWE systems are reviewed. Critical analysis of each method is performed to evaluate the best possible combination for development of a HOWWE system.

The untapped potential of wave energy offers another alternative to diversifying renewable energy sources and addressing climate change by reducing CO2 emissions. However, development costs to mature the technology remain significant hurdles to adoption at scale and the technology often must compete against other marine energy renewables such as offshore wind. Here, we conduct a real option valuation that includes the uncertain market price of wholesale electricity and managerial flexibility expressed in determining future optimal decisions. We demonstrate the probability that the project’s embedded compound real option value can turn a negative net present value wave energy project to a positive expected value. This change in investment decision uses decision tree analysis, where real options are developed as decision nodes, and models the uncertainty as a risk-neutral stochastic process using chance nodes. We also show how our results are analogous to a financial out-of-the-money call option. Our results highlight the distribution of outcomes and the benefit of a staged long-term investment in wave energy systems to better understand and manage project risk, recognizing that these probabilistic results are subject to the ongoing evolution of wholesale electricity prices and the stochastic process models used here to capture their future dynamics. Lastly, we show that the near-term optimal decision is to continue to fund ongoing development of a reference architecture to a higher technology readiness level to maintain the long-term option to deploy such a renewable energy system through private investment or private–public partnerships.

The study focuses on a semi-submersible wind-wave integrated power-generation platform, which consists of an OO-Star semi-submersible platform equipped with a DTU 10 MW wind turbine and a set of wave energy converters. A hydrodynamic model was established using ANSYS-AQWA (2023 R1), and by incorporating upper wind loads and utilizing the open-source program F2A, a fully coupled time-domain model of the integrated power-generation platform was constructed. The primary objective is to explore the interaction mechanisms between the upper wind turbine and the lower wave energy devices under the combined effects of irregular waves and turbulent wind through a series of operational conditions. Additionally, the safety of the mooring system was assessed. The results indicate that, compared to the wave period, the power generation of the lower wave energy devices is more significantly affected by wave height. Overall, the integrated power-generation platform demonstrates optimal performance under the third operational condition. In survival conditions, the introduction of oscillating buoys can improve the motion responses of the platform in terms of sway, roll, pitch, and yaw to a certain extent, but it also increases the surge and heave motion responses and the associated mooring loads. The mooring system can ensure the safety of the integrated power-generation platform under extreme sea conditions.

Coastal erosion is a growing concern for many regions, threatening infrastructure, ecosystems, and local communities. Conventional hard-engineering solutions often lead to negative environmental impacts and disrupt natural coastal dynamics, while retreat and adaptation strategies can sometimes be challenging to implement. In response, we have been developing an innovative, nature-based approach inspired by the wave and current dissipating capabilities of mangrove ecosystems.Mangroves, with their dense root systems, act as effective natural barriers, reducing wave energy, stabilizing sediments, and enhancing coastal resilience. Our project aims to replicate these benefits through a bio-inspired structure designed to mimic the intricate root networks of mangroves. This system uses strategically placed vertical and horizontal elements to dissipate wave energy and enhance sediment deposition, providing a sustainable method to control coastal erosion.The design and implementation of this solution resulted from a collaborative effort among coastal engineers, ecologists, and numerical modelers. Advanced hydrodynamic simulations were conducted to assess and optimize the wave dissipation performance of the structure. A pilot installation at Grau d'Agde beach, a vulnerable site on the French Mediterranean coast, has provided promising initial results. Early monitoring data show significant reductions in wave energy and increased sediment retention, with promising ecological trends, indicating this nature-based approach can enhance coastal stability without compromising the local ecosystem.This presentation will cover the design process, modelling results, and preliminary field data from the pilot project, illustrating the potential of bio-inspired solutions for addressing coastal erosion and providing insights for broader application in similar vulnerable coastal areas. Keywords: Coastal Erosion, Nature-Based Solutions, Mangrove-Inspired Design, Wave Dissipation, Pilot Project, Field Monitoring, uUpscalling, Hydrodynamic Modeling.

The access to the offshore wind resource in the deep sea requires the development of innovative solutions which reduce the cost of energy. Novel technologies propose the hybrid combination of wind and wave energy to improve the synergy between these technologies sharing costs, such as mooring and electrical connexion. This work proposes a novel hybrid wind and wave energy system integrating a floating offshore wind turbine with three-point absorbers wave energy converters (WECs). The WECs are an integral part of the floating structure and contribute significantly to the hydrostatic and dynamic stability of the system. Their geometry is optimised considering a cylindrical, semi-cylindrical and spherical shape for the Pantelleria case study. The cylindrical shape with the largest radius and the lowest height is the optimal solution in terms of reducing structural costs and maximising the performance of the WECs. The in-house hydrostatic stability tool and the time domain model MOST are used to optimise the WECs, with a combined meta-heuristic genetic algorithm with the Kriging surrogate model and a local Nelder–Mead optimization in the final simulations. The power of the WECs is estimated with both linear and variable motor flow hydraulic PTOs to obtain a more realistic electrical power generation. Generally, the hybrid device proved to be more competitive than the floating wind turbine alone, with a LCOE reduction up to 11%. Performance of the hybrid device can be further improved when more energetic sites are considered, as the energy generated by the WECs is higher.

Ocean waves are a consistent, reliable source of renewable energy, but major hurdles still exist before wave energy will be a viable grid power source. Several applications exist today that would benefit from a small stand-alone wave energy system. The goal of this project was to design, build and test a small wave energy converter to operate in the waters adjacent to the U.S. Naval Academy in Annapolis, MD, producing 50W average power. The result was a cylindrical heaving device with integrated oscillating water column, with outer diameter of 3.4 ft and total weight of 94.5 lbs. The design utilizes off-the-shelf components and 3D printed parts to minimize cost. Follow-on testing (both tank and field) will be conducted to evaluate performance of the concept design. This project serves as a foundation for future wave energy research and design projects.

Artificial intelligence (AI) and machine learning (ML) are becoming indispensable tools for increasing the efficiency and sustainability of this renewable energy source and the ocean energy industry has made significant strides in recent years. The initial stages of the industry research and development are when AI and ML first started to emerge in the wave and tidal energy space. The development, management, and upkeep of maritime energy systems have all changed as a result of these innovations. An massive, unexplored renewable resource that has the potential to make an important contribution to the world's energy mix is ocean wave energy. In order to maximize the efficacy and efficiency of wave energy conversion, this chapter focuses on the incorporation of artificial intelligence (AI) and machine learning technologies. It looks at these technologies' capability to support clean energy solutions and build a sustainable energy environment particularly in the context of urban living.

Wave energy characterization and assessment in the U.S. Gulf of Mexico, East and West Coasts with Energy Event concept

Floating offshore wind and wave energy are both promising marine renewable energy technologies that are still at an early stage of development. This paper reviews synergies between the two technologies that can be mutually beneficial and facilitate the path to commercial exploitation. The analysis focuses on three different types of combined wave and wind systems: Co-located arrays, hybrid systems and island systems. The decarbonisation potential of co-located systems is discussed. Existing carbon emissions from marine technologies are compared and how synergies can achieve these reductions are explored. A case study is presented to calculate the impact of multi-purpose platforms on the Portuguese energy system. Portugal was chosen because it has an excellent climate for marine resources, deep waters, positive political support for renewable marine energy and previous success in deploying first technology demonstrators for floating wind and wave energy systems.