A wave-to-wire analysis of the adjustable draft point absorber wave energy converter coupled with a linear permanent-magnet generator

An adjustable draft point absorber was recently proposed as a novel approach to improve power absorption with constrained power take-off (PTO) capacities. The key feature of the novel wave energy converter (WEC) concept is to adjust the buoy draft by regulating the ballast water inside the buoy, which aims to enable variation of the natural...

A spectral-domain wave-to-wire model of wave energy converters

Wave-to-Wire models play an important role in the development of wave energy converters. They could provide insight into the complete operating process of wave energy converters, from the power absorption stage to the power conversion stage. In order to cover a set of relevant nonlinear effects, wave-to-wire models are predominately...

Downsizing the Linear PM Generator in Wave Energy Conversion for Improved Economic Feasibility

A crucial part of wave energy converters (WECs) is the power take-off (PTO) mechanism, and PTO sizing has been shown to have a considerable impact on the levelized cost of energy (LCOE). However, as a dominating type of PTO system in WECs, previous research pertinent to PTO sizing did not take modeling and optimization of the linear permanent...

Low-head pumped hydro storage: A review of applicable technologies for design, grid integration, control and modelling

To counteract a potential reduction in grid stability caused by a rapidly growing share of intermittent renewable energy sources within our electrical grids, large scale deployment of energy storage will become indispensable. Pumped hydro storage is widely regarded as the most cost-effective option for this. However, its application is...

How offshore wind could become economically attractive in low-resource regions like Indonesia

The current focus of offshore wind industry and academia lies on regions with strong winds, neglecting areas with mild resources. Photovoltaics' cost reductions have shown that even mild resources can be harnessed economically, especially where electricity prices are high. Here, we study the technical and economic potential of offshore wind...

Subsea buoyancy and gravity energy storage system for deep-water applications: A preliminary assessment

This article presents a preliminary assessment of a subsea buoyancy and gravity energy storage system (SBGESS). The storage device is designed to power an off-grid subsea water injection system to be installed at the Libra oil field in Brazil at 2000 m below sea level. Two 12MW floating wind turbines provide the energy supply. The system...

The contribution of low-head pumped hydro storage to grid stability in future power systems

The pan-European power grid is experiencing an increasing penetration of Variable Renewable Energy (VRE). The fluctuating and non-dispatchable nature of VRE hinders them in providing the Ancillary Service (AS) needed for the reliability and stability of the grid. Therefore, Energy Storage Systems (ESS) are needed along the VRE. Among the...

A numerical study on the performance of the point absorber Wave Energy Converter integrated with an adjustable draft system

The Power Take-Off (PTO) rating of Wave Energy Converters (WECs) is generally much higher than the average extracted power. Scientific literature has indicated that downsizing the PTO capacity to a suitable level is beneficial for improving the techno-economic competitiveness. In this paper, a novel design, namely the adjustable draft system,...

The application of the spectral domain modeling to the power take-off sizing of heaving wave energy converters

The power take-off (PTO) system is a main component in wave energy converters (WECs), and it accounts for a notable proportion in the total cost. Sizing the PTO capacity has been proven to be significant to the cost-effectiveness of WECs. In the numerical modeling, the PTO size is normally represented by a force constraint. Therefore, to...

Digital Twins for Wind Energy Conversion Systems: A Literature Review of Potential Modelling Techniques Focused on Model Fidelity and Computational Load

The Industry 4.0 concept of a Digital Twin will bring many advantages for wind energy conversion systems, e.g., in condition monitoring, predictive maintenance and the optimisation of control or design parameters. A virtual replica is at the heart of a digital twin. To construct a virtual replica, appropriate modelling techniques must be...

Integration of Wind Energy and Desalination Systems: A Review Study

Desalination is a well-established technology used all over the world to mitigate freshwater scarcity. Wind-powered reverse osmosis plants are one of the most promising alternatives for renewable energy desalination, particularly for coastal areas and islands. Wind energy can satisfy the high energy consumption of desalination while reducing...

The Influence of Linear Permanent Magnet Generator Sizing on the Techno-Economic Performance of a Wave Energy Converter

Downsizing the Power Take-off (PTO) rating has been proven to be beneficial for decreasing the Levelized Cost of Energy (LCOE) of wave energy converters (WECs). However, the linear permanent magnet (PM) generator has not yet been modelled and optimized in detail in previous feasibility studies. This paper extends the study of the PTO...

Gyroscopically enhanced vertical axis pendulum for wave energy conversion

The vertical axis pendulum is a type of point absorber device which can absorb wave energy from a width exceeding the physical width of the device. Mechanical power is harvested from the rotation of the pendulum, in which the pivot point is directly connected to the generator. In this paper, a new concept of the vertical axis pendulum device is...

Integration of hydraulic wind turbines for seawater reverse osmosis desalination

The integration of renewable energy sources to power seawater desalination is crucial to mitigate CO2 emissions and to face the increasing challenges that are stressing fresh water resources depletion. In particular wind energy is one of the most cost-effective forms of renewable energy with a high potential to reduce the seawater desalination's...

Modelling of submerged oscillating water columns with mass transfer for wave energy extraction

Oscillating-water-column (OWC) devices are a very important type of wave energy converters which have been extensively studied over the years. Although most designs of OWC are based on floating or fixed structures exposed above the surface level, little is known from completely submerged systems which can benefit from reduced environmental...

Centralized electricity generation in offshore wind farms using hydraulic networks

The work presented in this thesis explores a new way of generation, collection and transmission of wind energy inside a wind farm, in which the electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A centralized approach for electricity generation is considered...

Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines: A Parameter Study

In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed wind turbines and shows a parametric study on...