A New Method for Extracting Ocean Wave Energy Utilizing the Wave Shoaling Phenomenon

Fossil fuels are the major source to meet the world energy requirements but its rapidly diminishing rate and adverse effects on our ecological system are of major concern. Renewable energy utilization is the need of time to meet the future challenges. Ocean energy is the one of these promising energy resources. Threefourths of the earth-s surface is covered by the oceans. This enormous energy resource is contained in the oceans- waters, the air above the oceans, and the land beneath them. The renewable energy source of ocean mainly is contained in waves, ocean current and offshore solar energy. Very fewer efforts have been made to harness this reliable and predictable resource. Harnessing of ocean energy needs detail knowledge of underlying mathematical governing equation and their analysis. With the advent of extra ordinary computational resources it is now possible to predict the wave climatology in lab simulation. Several techniques have been developed mostly stem from numerical analysis of Navier Stokes equations. This paper presents a brief over view of such mathematical model and tools to understand and analyze the wave climatology. Models of 1st, 2nd and 3rd generations have been developed to estimate the wave characteristics to assess the power potential. A brief overview of available wave energy technologies is also given. A novel concept of on-shore wave energy extraction method is also presented at the end. The concept is based upon total energy conservation, where energy of wave is transferred to the flexible converter to increase its kinetic energy. Squeezing action by the external pressure on the converter body results in increase velocities at discharge section. High velocity head then can be used for energy storage or for direct utility of power generation. This converter utilizes the both potential and kinetic energy of the waves and designed for on-shore or near-shore application. Increased wave height at the shore due to shoaling effects increases the potential energy of the waves which is converted to renewable energy. This approach will result in economic wave energy converter due to near shore installation and more dense waves due to shoaling. Method will be more efficient because of tapping both potential and kinetic energy of the waves.

Authors:

• Shafiq R. Qureshi
• Syed Noman Danish
• Muhammad Saeed Khalid

Keywords:

• Energy Utilizing
• Wave Shoaling Phenomenon

References:

[1] M. Folley, T.J.T. Whittaker. Analysis of the nearshore wave energy
resource, Renewable Energy 34 (2009) 1709-1715.
[2] M. French On the difficulty of inventing an economical sea wave
energy converter: a personal view, Proceedings of the I MECH E Part
M, Volume 220, Number 3, 2006 , pp. 149-155(7)
[3] J. M. Leishman & G. Scobie,"The development of wave power - a
techno economical study", Dept. of Industry, NEL Report, EAU M25
(1976)
[4] T. Lewis "Wave Energy - Evaluation for C.E.C", EUR9827EN, (1985)
[5] Kevin A Haas and Hermann M Fritz, Ocean Energy Potential in
Southeast Georgia, A report.
[6] S. H. Salter. "World progress in wave energy - 1988". The international
Journal of Ambient Energy. Vol. 10 (1) (1989).
[7] T. W. Thorpe , "A Review of Wave Energy", ETSU-R-72 (1992)
[8] D. Ross "Power from the Waves", Oxford University Press (pub.)
(1995),
[9] Beddhu, M., Taylor, L., Whitfield, D.,. A time accurate calculation
procedure for flows with a free surface using a modified artificial
compressibility formulation. Applied Mathematics and Computation 65
(1), 33-48 (1994)
[10] A. Chorin The numerical solution of the Navier-Stokes equations for an
incompressible fluid. Report NYO-1480-82. New York University
(1967).
[11] F. Kelecy, R. Pletcher The development of a free surface capturing
approach for multidimensional free surface flows in closed containers.
Journal of Computational Physics 138, 939-980 (1997).
[12] Julien De Rouck , Hadewych Verhaeghe, and Jimmy Geeraerts Crest
level assessment of coastal structures ÔÇö General overview. Coastal
Engineering Volume 56, Issue 2, February (2009)
[13] D.M. Ingram, D.M. Causon, F. Gao, C.G. Mingham, P. Troch, T. Li and
J. De Rouck, Free surface numerical modelling of wave interaction with
coastal structures. Clash Final Report on WP5 www.clash-eu.org
(2005)
[14] Goda, Y., Irregular wave deformation in the surf zone. Coastal
Engineering in Japan 18, 13-26 JSCE (1975).
[15] Y. Goda, A performance test of nearshore wave height prediction with
CLASH datasets, Coastal Engineering 56 (2009) 220-229, (2009).
[16] Charles L. Mader Numerical Modeling Of Water waves, 2nd Edition
[17] Technology White Paper on Wave Energy Potential on the U.S. Outer
Continental Shelf, Minerals Management Service Renewable Energy
and Alternate Use Program U.S. Department of the Interior , (2006),
Available for Downloading at http://ocsenergy.anl.gov
[18] G. Hagerman and R. Bedard, Guidelines for Preliminary Estimation of
power production by offshore wave energy conversion devices, EPRI
Report E21 EPRI-WP-US-001 (2003)
[19] Patent No. WO 2007125538 20071108
[20] Pelamis Wave Power Ltd, 2008. Homepage
http://www.pelamiswave.com/index.php
[21] Therese Pontes, Mathematical description of Waves and Wave energy,
INETI department of Renewable Energy, Lisbon, Portugal, December
2002
[22] T. Thorpe "An Overview of Wave Energy Technologies: Status,
Performance and Costs". "Wave power - Moving towards commercial
viability", IMECHE Seminar, London, UK (1999).
[23] Syed Sibte Ahmed Jafri Ocean-Based Power and Its Huge Potential as a
Renewable Energy Source , a report.
[24] www.carbontrust.co.uk/technology/technologyaccelerator/
ME_guide2.htm
[25] http://www.nasa.gov/topics/earth/features/tideenergy.html
[26] http://www.epsrc.ac.uk/PressReleases.
[27] Leão Rodrigues, Wave power conversion systems for electrical energy
production. A report by Department of Electrical Engineering Faculty of
Science and Technology, Nova University of Lisbon.
[28] D. Hoffman and O.J. Karst. The theory of the Rayleigh distribution and
some of its applications. Journal of Ship Research 19 (3): 172-191 (
1975).
[29] O. M Phillips "On the generation of waves by turbulent wind." J. Fluid
Mech., 2, 417-445 (1957).
[30] J. W. Miles "On the generation of surface waves by shear flows." J.
Fluid Mech., 3, 185-204 (1957).
[31] R. E. Jensen. "Spectral wave modelling technology". Coastal and
Hydraulics Engineering Technical Note CHETN-I-58, U.S. Army
Engineer Waterways Experiment Station, Vicksburg, MS (1994).
[32] F. Ardhuin, ÔÇÿMomentum balance in shoaling gravity waves: Comment
on ÔÇÿShoaling surface gravity waves cause a force and a torque on the
bottom- by K. E. Kenyon- J. Oceanogr., 62, 917-922.