The group has been very active in the area for quite some time and continues to be so. Achievements from last century are summarised at the bottom of this page. Key achievements by the present team include being involved in EPSRC's supergen 1 and 2, working with the Carbon Truston its marine accelerator programme and being involved in the development of NaREC's linear Test Rig. We are presently funded by EPSRC and industrial sources for work in wave energy.
The group has experience and expertise in tank testing, hydrodynamic modelling, device capture and
control. We are presently investigating several different device concepts as well as conducting valuable
generic work. We have the capability and desire to independently evaluate new devices.
Some examples of video footage showing devices in our wave tank can be found in the facilites page. Details of work on specific ongoing, planned or completed projects are given below.
Lancaster is invovled in furthering the development of several devices. We are particularly attracted to surging point absorbers. The attraction of devices which move in surge is the mathematical proof that they are theoretically able to capture more energy than there heaving counterparts. Several aspects of surging point absorbers are being considered at LU.
The WRASPA - a bed mounted surging wave energy converters
Experience at LU is now being channeled into a bed mounted surging wave energy device. More details on the WRASPA here
Numerical Modelling, Prediction and Control
Optimisation of Collector Form and Response
Do optimal designs exist for the physical form and response of the collector in a wave energy converter? If so, can the constraints, parameters and cost function necessary for a systematic optimisation be defined? This project examines these questions through the use of Genetic Algorithms to assist in the optimal design of the collector shape of wave energy converters and assess it's performance in realistic sea conditions. Details
Prediction and Control of Wave Energy Converters in Irregular Seas
This project, co-funded by EOn, project will use experimentally verified hydrodynamic modelling to predict the performance of generic wave energy converters. These models will be subsequently used to compare strategies suitable for controlling deep water devices. Details
In order to maximise the power taken out of a wave energy device, it is likely that they will be controlled. A floating device has a natural and hence resonating frequency. Manipulation of this frequency will alter the power take out characteristics.
Time Domain Modelling
Modelling wave energy converters in mixed seas in real time is essential for accurate economic modelling and understanding device behaviour. More details on our work in this area.
Power Take Off
Linear Generators with Hydrostatic Bearings
A modular design for Linear generators potentially reduces generator downtime by almost 100%. Modules are replaceable whilst the generator is running resulting in little or no downtime and reduced operation and maintainance costs.. More.
Power Take out in irregular seas
Reliable estimates of revenue for a wave energy device can only be obtained by considering their performance in irregular waves. Often, economics are based on simulations using regular waves and mapping the results to expected climates. More.
How do alternative concepts compare?
The economics of wave energy converters covers is likely to decide which devices are developed in the long term. this work aims to explore how engineering decisions influence the economics of marine energy schemes at different scales of electricity production. More.
LUREG can offer advice and help on device concept evaluation in a variety of ways. More.
Power Take Off
Linear Generators for drive power take off
The slow speed reciprocating nature of many wave energy devices does not lend itself to using high speed electrical machines as a source of power take off. This has often led wave energy device designers to either use hydraulic systems or develop complex mechanical linkages. An alternative approach is to develop electrical machines specifically for this application. more.
Members of Lancaster University have been researching in to wave energy since the 1970s. A summary of the key devices is given below
The Flounder consists of a number of bodies moving back-wards and forwards in the direction of the waves (in surge).The structural elements are cables, pre tensioned to enable them to transmit the alternating wave forces, and the bodies are inflatables filled mainly with sea-water. Research highlighted problems of power take-off and capture maximisation.
Lancaster Flexible bag
The Lancaster Floating Bag, investigated first in the mid 1970s, had a ship-like hull lying roughly head-on to the prevailing seas, with rows of flexible bags down each side side. The bags were partially filled with air, which was forced through a set of non return valves and across a turbine by the action of the waves on the bags. This pioneering work unfortunately concluded that the structural costs would be prohibitively high, in the region of 63% of the total cost.
This device, the parent of the PS Frog still being developed, was borne out of the idea of making a reaction less wave energy
converter for deepwater locations. Where as many wave energy converters convert power by virtue of parts of the device moving relative to each other, a buoy and
drag plate for example, the Frog reacts against an internal mass. The device operates in heave, and power take off is by wave of resisting an internal mass
mounted on a spring.
Experimental observations of the excessive pitching of the device in combination with concerns of the device cap-sizing and ejecting the mass under the force of the spring, lead to moving the sliding mass to act in a horizontal direction. In this manner, the Frog capitalises on the power converted in the pitch and surge (PS) mode and lead to the second mutation of the device, the P S Frog.
Page under construction.
Page under construction.
Wave Energy Research Projects
The science behind behind electricity generation from the energy of sea waves is of utmost importance in understanding the nature and ability of wave energy devices. These pages will provide basic information on the overriding priciples through which our research is done, including links to projects external to LUREG.