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In this paper, the response and the power absorption ability of the TALOS multi-mode WEC are preliminarily assessed for various environmental and operational conditions, by deploying two different computational tools and assuming linear mooring lines’ behavior. The device consists of an internal sphere attached to its floater with springs and dampers, while power is absorbed through the sphere’s motions relatively to the floater. A comparative study is, initially, conducted assuming rigid connection of the sphere with the floater. Next, by enabling the sphere to oscillate in heave, as well as in both heave and surge, the device’s performance for one and two operational modes is assessed. The two-mode PTO mechanism operation results in an increased power absorption of the device (max mean value of 238 kW) and in insignificant effects in motion responses.

Wave energy provides a renewable and clear power for the future energy mix and fights against climate change. Currently, there are many different wave energy converters, but their costs of extracting wave energy are still much higher than other matured renewables. One of the best indicators of calculating the generating cost of wave energy is the ‘levelized cost of energy’ (LCOE), which is the combined capital expenditure (CAPEX), operational expenditure (OPEX), and decommissioning cost with the inclusion of the annual energy production, discount factor, and project’s lifespan. However, the results of the LCOE are in disagreement. Hence, it is important to explore the cost breakdown of wave energy by the wave energy converter (WEC), so for finding potential ways to decrease the cost, and finally compare it with other renewable energies. Different WECs have been installed in the same place; the Wave Dragon LCOE platform is the best one, with an energy conversion of EUR 316.90/MWh, followed by Pelamis with EUR 735.94/MWh and AquaBuOY with EUR 2967.85/MWh. Even when using different locations to test, the rank of the LCOE would remain unchanged with the different value. As the CAPEX and OPEX dramatically drop, the availability and capacity factors slowly increase, and the LCOE decreases from a maximum of USD 470/MWh to a minimum of USD 120/MWh. When the discount rate is down from 11% to 6%, the LCOE reduces from USD 160/MWh to USD 102/MWh. Under the ideal condition of the optimal combination of multiple factors, in theory, the LCOE can be less than USD 0.3/KWh. To better explore the LCOE for WECs, the detailed cost elements found in the CAPEX and OPEX have been examined for the scenarios of the undiscounted, half-discounted, and discounted cost models. When the AEP is discounted, the lowest LCOE is equal to USD 1.171/kWh in scene 2 when using a five-step investment, which is below the LCOE value of USD 1.211/kWh in scene 1 when using a two-step investment. Meanwhile, th

TALOS wave energy converter is a point absorber proposed at Lancaster University (UK), with its main advantage being its ability to absorb energy from all motion modes (i.e. multi-axis Power-Take-Off system). Following previous computational studies in the frame of device development (including frequency-domain modelling), here we present a motion study response for the TALOS wave energy converter for selected wave climates. The analysis applies to realistic irregular wave conditions, assuming a semi-empirical spectrum representative of chosen wave climates, and hydrodynamic modelling is combined with Copernicus Marine Service wave reanalyses data. After scatter plots of significant wave height and energy period are prepared, future considerations are discussed for the device size adjustments under different wave climates

This paper focuses on the preliminary time-domain analysis of a multimode Wave Energy Converter (WEC), the so-called TALOS WEC, by deploying two different computational tools. The device consists of an internal sphere attached to its floater with springs and dampers, and power is captured through the sphere’s motions relatively to the floater. The equation of motion is formed based on the Cummins formulation using different calculation approaches for the convolution terms in the two tools. A comparative study, initially, is conducted assuming rigid connection of the sphere with the floater. Next, by enabling the sphere to oscillate in heave, as well as in both heave and surge, the device’s performance for one and two operational modes is assessed

The present study provides details on the power capture performance of TALOS WEC based on PTO system parameters. Considering that only surge, heave and pitch modes of motions are directly coupled to the incident sea waves. Hence, the model is defined to be a 3 DOF model. The PTO system is modelled by using ideal elements. The study focuses on surge, heave and pitch modes. The objective of the study is to evaluate the power capture performance of the system and it is shown that the system performs well for sea states with Hs of 2 meters or higher

Most creatures are highly adapted to the environment for survival through the evolutionary process and developing useful biological features for design inspirations could improve the performance of Wave Energy Converters (WECs), such as the TALOS WEC. A method of obtaining biological inspiration to conceive novel design is provided in this paper. The current situation of wave energy utilization is described and a number of problems in the research and development of WECs are introduced. The structure, motion and other characteristics of TALOS WEC are analyzed. Finally, the method is validated with TALOS WEC followed by discussion and conclusions.

Panel methods based on potential flow theory have been widely employed for wave-structure interactions, since these methods could provide fast, reliable and accurate predictions for the forces acting on and the motions of the marine structures if the strong nonlinear forces are not included in the analyses. In reality, some panel methods can be regarded as the industry standards, and also some open sources are available. The comparisons in this research work include: 1) the comparison between WAMIT and HAMS; 2) the comparisons to see the improvement using the options of irregular frequency removal (IRR); 3) the comparisons on the original TALOS and the circular TALOS; 4) the comparison for the incomplete panels on the circular TALOS; 5) the comparison for the overlapped panels on the circular TALOS.

Optimal control techniques can oversee the power take off (PTO) operation of wave energy conversion systems to ensure that the overall power output is maximized, but optimization in real-time poses difficulties given the wave variability and the underlying constraints of the system. This study examines several different model predictive control (MPC) approaches that utilize a model of the hydrodynamics of the wave energy converter as well as the dynamics of a hydraulic PTO system. The impact of accounting for various dynamics in the optimization and the role of constraints on the wave energy converter performance is explored for irregular wave conditions.

Wave energy shows potential to provide electricity in a renewable manner. The TALOS WEC (Wave Energy Converter) is a unique design with six PTO (Power Take-Off) elements to provide six Degrees of Freedom (DOFs), which is potentially able to harvest energy more efficiently than traditional single-DOF devices. As a step towards its optimisation and control, a power prediction model is developed, using the wave elevation and motions of the WEC to predict the power output of each PTO. The results show that using LSTM (Long-Short Term Memory) has a higher prediction accuracy than the other approaches considered.

The Lancaster in-house code is a time-domain analysis code, developed especially for the TALOS wave energy converter, a novel wave energy conversion technology. The TALOS wave energy converter is a point absorber-like wave energy converter, but with a unique power take-off (PTO) system. The whole PTO system is fully enclosed within the structure, hence no moving parts are exposed to the harsh marine environments. The PTO of the TALOS WEC consists of a mass ball within the structure, with a number of springs and dampers (for instance, direct drives or hydraulic systems) connecting between the mass ball and the structure. Such an arrangement of the PTOs would make the PTO essentially non-linear, regardless whether the actual PTO dampers are linear or nonlinear as well as the linear springs. Therefore, a time domain analysis must be established for the TALOS WEC. Towards the goal, an in-house time-domain model has been developed at Lancaster University, and now it is to be validated via the delicated numerical models built using well-established commercial software (and in the future via experimental data). Within this framework, the present paper presents an effort for validation using the DNV SESAM commercial hydrodynamic and structural analysis software. To build a numerical model for TALOS WEC, the Lancaster in-house time domain code is based on the hybrid frequency-time domain approach. That is, the basic hydrodynamic parameters are analysed using the panel methods (WAMIT, HAMS, NEMOH), and then the relevant parameters are transformed for the Cummins’ time-domain equation, such as the added mass at infinite frequency, and the memory effect (the convolution terms). This work is an extension of the comparison between the in-house code and the DNV SESAM software, and the comparisons would include the relevant hydrodynamic analyses, the time-domain analyses with and without the TALOS PTO system, with the aims towards developing the validated tools of both the in-house

The TALOS wave energy converter is a novel point absorber-like wave energy converter (WEC), in which a unique power take-off (PTO) system is fully enclosed within the structure of the TALOS WEC (the hull), so to avoid direct contact with the harsh marine environment. This specific WEC is being investigated and developed at Lancaster University (UK), and the numerical modelling implementation of the TALOS wave energy converter is one of the main tasks of the Lancaster in-house time-domain analysis code. The PTO system of TALOS WEC consists of a heavy mass ball within the structure, which is linked with a number of linear springs and dampers to the hull of TALOS WEC for wave energy conversion. Such an arrangement of the PTOs could in principle convert the energy from all motion modes of the wave energy converter, but it would also make the PTO essentially non-linear, regardless the actual PTO damper’s characteristics (linear or nonlinear). Therefore, a time domain analysis must be established for the TALOS WEC, which is the research work in this investigation.

As global energy demands and climate concerns continue to grow, the need for renewable energy is becoming increasingly clear and wave energy converter (WEC) systems are receiving growing interest. WECs often utilize optimal control techniques for power take-off operation and leverage a prediction of the upcoming wave force to ensure power production optimization. Prior work has clearly demonstrated that high power production can be achieved when an exact system model is used and the upcoming wave conditions are known, but uncertainty in the underlying model or the wave prediction can degrade performance. The uncertainty in these predictions and the model could degrade the WEC’s power output. This work examines the impact of uncertainty on the control of a WEC system that leverages machine learning to predict wave forces over the upcoming time horizon. This paper quantifies wave prediction uncertainty and its seasonal variation and illustrates that this uncertainty may only minimally degrade power output on complex multi-axis WECs due to the strong influence of constraints in the system.

Harnessing the untapped potential of wave energy demands advanced modelling tools that accurately represent wave energy converters (WECs) and facilitate the optimization of their designs. This paper introduces two new numerical models of the TALOS WEC concept currently under development by Lancaster University, UK [1]. In this project we employ HydroChrono - a fully opensource hydrodynamics package for the open-source multibody dynamics software, Project Chrono [2]. HydroChrono enables potential flow-based modelling of WECs and offers the flexibility to explore various design configurations, which is demonstrated in the results section. Confidence in our model’s accuracy is established via comparisons with Computational Fluid Dynamics (CFD) simulations, performed with Ansys Fluent. HydroChrono enables us to vary key design parameters of the TALOS WEC, including mass distribution and Power Take-Off (PTO) properties - which can offer insights for future design improvements. Looking ahead, the application of HydroChrono for WEC numerical modelling offers pathways to more sophisticated analyses. This includes potential integration with the MoorDyn package for nonlinear mooring dynamics, and the possibility of detailed hydraulic drivetrain modeling. These developments facilitate more detailed performance prediction and system optimization for wave energy conversion technology, leading to more cost-effective and efficient marine renewable energy solutions.