Using Energy Storage for Novel Control of Off-Grid and On-Grid Wave Energy Arrays

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Engineering

Abstract

This work assesses the feasibility of using energy storage to make a step-change improvement in control for off-grid and on-grid wave energy arrays. This has been brought about by a need for arrays of smaller wave energy devices to utilise the less-energetic wave resource off the coast of China. For a lower energy resource, control of arrays is even more important in order to optimise performance and to improve survivability. As the focus is on future deployment of arrays in China, the step-change is only possible with the expertise in wave climate, off-grid connection of devices and power systems in China; hence this contribution is provided by project partners in China.

Planned Impact

With such a differing wave energy resource, Chinese developers cannot simply replicate and bring European devices and facilities (such as Pelamis) to East Asia. Deploying an array of optimally controlled smaller wave energy converters can be a solution, and this has been recognised as a need in China. The work in this project benefits wave energy technology developers who are considering array development and the challenges involved. The work will help to promote and instil confidence in the potential of wave energy arrays as a feasible method of generating clean electricity. In the short term, users of this research would be researchers in wave energy who can apply the proposed techniques in control and modelling. The bigger picture is that the work will make a significant contribution to wave energy array development in UK and China to reduce carbon emissions and generate electricity by sustainable means, to the benefit of both countries and its people.
 
Description Through this research, an electrical wave energy converter array model has been developed which integrates energy storage to improve performance of the array. Through this model, the project recommends a suitable sizing and location for the energy storage system, which has a large impact on the overall performance of the array. It was found that by separating the energy storage in to two distinct parts, the losses in the system is reduced and the performance of the control system is improved.
Exploitation Route The findings can be implemented in array models for different wave energy converters.
Sectors Electronics,Energy

 
Description Joint UK-China Offshore Renewable Energy
Amount £809,108 (GBP)
Funding ID EP/R007756/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 07/2017 
End 06/2020
 
Title Electrical model of an off-grid wave energy converter array 
Description This is a model of an array of wave energy converters which are electrically connected. Each wave energy converter can be controlled individually using a direct-drive power take-off system. As the array is not connected to the electrical network, energy storage is required to provide reactive power. The energy storage system is divided into 2 parts - converter-based storage and land-based storage. This improves performance of the control system and minimises losses in power transmission. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact The model can be used to help device developers understand the electrical operation of arrays without the need for extensive wet testing. We are currently working with device developers to explore the use of the array model. 
 
Description Lecture at Hohai University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Lecture given to academic staff, and postgraduate students at Hohai University on marine energy, energy storage, and power conversion. This increased interest among the attendees and promoted the research undertaken at the University of Edinburgh.
Year(s) Of Engagement Activity 2014
 
Description Lecture at Ocean University of China 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Lecture given to academic staff, and postgraduate students at Ocean University of China on marine energy, energy storage, and power conversion. Progress on the funded project was also presented. This increased interest among the attendees and promoted the research undertaken at the University of Edinburgh.
Year(s) Of Engagement Activity 2015