Life cycle comparison of a wave and tidal energy device

2011 ◽  
Vol 225 (4) ◽  
pp. 325-337 ◽  
Author(s):  
S Walker ◽  
R Howell
Keyword(s):  
Life Cycle ◽  
Wave Energy ◽  
Tidal Energy ◽  
Development Stage ◽  
Payback Period ◽  
Energy Device ◽  
Energy Mix ◽  
Energy Devices ◽  
Marine Energy ◽  
Marine Current

Tidal and wave energy devices are often discussed as a future contributor to the UK’s energy mix. Indeed, marine energy resources are said to have the potential to supply up to 20 per cent of the nation’s electricity demand. However, these technologies are currently at the development stage and make no meaningful contribution to the national grid. A number of devices have been developed, but no single method has emerged as the leading technology. This paper aims to compare two promising devices, one wave device and one tidal device, and assess the life cycle properties of each. A life cycle assessment of the Oyster wave energy device was conducted as part of this study, and a comparison of this and the SeaGen marine current turbine was undertaken. In both cases a ‘cradle-to-grave’ assessment was carried out, calculating emissions from materials, fabrication, transport, installation, lifetime maintenance, and decommissioning (including recycling). The SeaGen tidal device was calculated to have an energy payback period of 14 months, and a CO2 payback period of 8 months. The equivalent figures for the Oyster device were 12 and 8 months, respectively. The respective energy and carbon intensities for the two devices were 214 kJ/kWh and 15 gCO2/kWh for the SeaGen and 236 kJ/kWh and 25 gCO2/kWh for the Oyster. The calculated intensities and payback periods are close to those of established wind turbine technologies, and low relative to the 400–1000 g CO2/kWh of typical fossil fuel generation. With further developments in construction and deployment efficiency these intensities are expected to fall, so the devices appear to have the potential to offer a viable contribution to the UK’s future energy mix.

Floating Wave Energy Device With Two Oscillating Water Columns

2007 ◽  
Author(s):  
D. C. Hong ◽  
S. Y. Hong
Keyword(s):  
Green Function ◽  
Wave Energy ◽  
Numerical Results ◽  
The Body ◽  
Energy Device ◽  
Energy Devices ◽  
Damping Parameter ◽  
Absorbed Power ◽  
Linear Damping ◽  
Drift Force

The absorbed power, motion and drift force of a floating wave energy device with two oscillating water column (OWC) chambers are studied taking account of the interaction between two chambers within the scope of the linear wave theory. The oscillating surface-pressure in the OWC chamber is represented by a product of the air-flow velocity and an equivalent linear damping parameter. The two-dimensional potential problem is formulated as a hybrid Green integral equation using the Rankine Green function inside the chamber and the finite-depth free-surface Green function outside respectively. The present numerical method makes it possible to tune the OWC and the floating body motions to the incident waves that is essential to maximize the absorbed power. The absorbed powers are calculated by both the near-field and far-field methods for various values of the linear damping parameter in two chambers. The reflection and transmission coefficients of the body are also presented. The numerical results for one OWC devices where the OWC is placed in a backward and forward bent duct buoys (BBDB and FBDB) are also presented for comparison of the performance. The present floating wave energy devices can also be served as a good floating breakwater having small drift force. The present numerical results show that the existence of reverse time-mean horizontal wave drift force is not contradictory to the principle of wave energy conservation.

scholarly journals Fluid-Structure-Soil Interaction of a Moored Wave Energy Device

2019 ◽  
Author(s):  
Joe G. Tom ◽  
Dirk P. Rijnsdorp ◽  
Raffaele Ragni ◽  
David J. White
Keyword(s):  
Cyclic Loading ◽  
Wave Energy ◽  
Significant Proportion ◽  
Interdisciplinary Approach ◽  
Cost Effective ◽  
Wave Flow ◽  
Energy Device ◽  
Subsequent Increase ◽  
Operational Conditions ◽  
Energy Devices

Abstract This paper explores the response of a wave energy device during extreme and operational conditions and the effect of this response on the geotechnical stability of the associated taut moorings. The non-hydrostatic wave-flow model SWASH is used to simulate the response of a taut-moored wave energy converter. The predicted forces acting on the mooring system are used to compute the build-up of excess pore pressures in the soil around the mooring anchor and the resulting changes in strength and capacity. An initial loss of strength is followed by a subsequent increase in capacity, associated with long-term cyclic loading and hardening due to consolidation. The analyses show how cyclic loading may actually benefit and reduce anchoring requirements for wave energy devices. It demonstrates the viability of a close interdisciplinary approach towards an optimized and cost-effective design of mooring systems, which form a significant proportion of expected capital expenditures.

scholarly journals On Wave-Induced Elastic Deformations of a Submerged Wave Energy Device

2020 ◽  
Vol 19 (3) ◽  
pp. 317-338
Author(s):  
Shuijin Li ◽  
Masoud Hayatdavoodi ◽  
R. Cengiz Ertekin
Keyword(s):  
Nonlinear Wave ◽  
Wave Energy ◽  
Structural Integrity ◽  
Accurate Determination ◽  
Elastic Response ◽  
Wave Loads ◽  
Extreme Wave ◽  
Energy Device ◽  
Energy Devices ◽  
Wave Induced

Abstract Structural integrity has remained a challenge for design and analysis of wave energy devices. A difficulty in assessment of the structural integrity is often laid in the accurate determination of the wave-induced loads on the wave energy devices and the repones of the structure. Decoupled hydroelastic response of a submerged, oscillating wave energy device to extreme nonlinear wave loads is studied here. The submerged wave energy device consists of an oscillating horizontal disc attached to a direct-drive power take-off system. The structural frame of the wave energy device is fixed on the seafloor in shallow water. Several extreme wave conditions are considered in this study. The nonlinear wave loads on members of the submerged structure are obtained by use of the level I Green-Naghdi equations and Morison’s equation for cylindrical members. Distribution of Von Mises stresses and the elastic response of the structure to the extreme wave loads are determined by use of a finite element method. The decoupled hydroelastic analysis of the structure is carried out for devices built by four different materials, namely stainless steel, concrete, aluminium alloy, and titanium alloy. The elastic response of these devices is studied and results are compared with each other. Points of maximum stress and deformations are determined and the structural integrity under the extreme conditions is assessed. It is shown that the proposed approaches provide invaluable information about the structural integrity of wave energy devices.

Life Cycle Assessment for the ISWEC Wave Energy Device

2020 ◽  
pp. 515-523
Author(s):  
Andrea Di Muro ◽  
Sergej Antonello Sirigu ◽  
Giuseppe Giorgi ◽  
Raffaella Gerboni ◽  
Giovanni Bracco ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Wave Energy ◽  
Energy Device

Tidal Energy in Nova Scotia, Canada: The Fundy Ocean Research Center for Energy (FORCE) Perspective

2011 ◽  
Author(s):  
Douglas J. Keefe ◽  
Joseph Kozak
Keyword(s):  
Nova Scotia ◽  
Power Systems ◽  
Tidal Energy ◽  
Test Site ◽  
The United States ◽  
Research Center ◽  
Ocean Energy ◽  
Overhead Transmission Line ◽  
Marine Energy ◽  
Marine Current

Ocean energy developments are appearing around the world including Scotland, Ireland, Wales, England, Australia, New Zealand, Japan, Korea, Norway, France Portugal, Spain, India, the United States, Canada and others. North America’s first tidal energy demonstration facility is in the Minas Passage of the Bay of Fundy, near Parrsboro, Nova Scotia, Canada. The Fundy Ocean Research Center for Energy (FORCE) is a non-profit institute that owns and operates the facility that offers developers, regulators, scientists and academics the opportunity to study the performance and interaction of instream tidal energy converters (usually referred to as TISECs but called “turbines” in this paper.) with one of the world’s most aggressive tidal regimes. FORCE provides a shared observation facility, submarine cables, grid connection, and environmental monitoring at its pre-approved test site. The site is well suited to testing, with water depths up to 45 meters at low tide, a sediment -free bedrock sea floor, straight flowing currents, and water speeds up to 5 meters per second (approximately 10 knots). FORCE will install 10.896km of double armored, 34.5kV submarine cable — one for each of its four berths. Electricity from the berths will be conditioned at FORCE’s own substation and delivered to the Provincial power grid by a 10 km overhead transmission line. There are four berth holders at present: Alstom Hydro Canada using Clean Current Power Systems Technology (Canada); Minas Basin Pulp and Power Co. Ltd. with technology partner Marine Current Turbines (UK); Nova Scotia Power Inc. with technology partner OpenHydro (Ireland) and Atlantis Resources Corporation, in partnership with Lockheed Martin and Irving Shipbuilding. In November 2009, NSPI with technology partner OpenHydro deployed the first commercial scale turbine at the FORCE site. The 1MW rated turbine was secured by a 400-tonne subsea gravity base fabricated in Nova Scotia. The intent of this paper is to provide an overview of FORCE to the international marine energy community during OMAE 2011 taking place in Rotterdam, Netherlands.

scholarly journals A novel wave-energy device with enhanced wave amplification and induction actuator

2020 ◽  
Vol 3 (1) ◽  
pp. 37-44
Author(s):  
Onno Bokhove ◽  
Anna Kalogirou ◽  
David Henry ◽  
Gareth P. Thomas
Keyword(s):  
Variational Principle ◽  
Numerical Model ◽  
Energy Conversion ◽  
Wave Energy ◽  
Electrical Power ◽  
Rogue Waves ◽  
Energy Device ◽  
Wave Amplification ◽  
Energy Devices ◽  
New Device

A novel wave-energy device is presented. Both a preliminary proof-of-principle of a working, scaled laboratory version of the energy device is shown as well as the derivation and analysis of a comprehensive mathematical and numerical model of the new device. The wave-energy device includes a convergence in which the waves are amplified, a constrained wave buoy with a (curved) mast and direct energy conversion of the buoy motion into electrical power via an electro-magnetic generator. The device is designed for use in breakwaters and it is possible to be taken out of action during severe weather. The new design is a deconstruction of elements of existing wave-energy devices, such as the TapChan, IP wave-buoy and the Berkeley Wedge, put together in a different manner to enhance energy conversion and, hence, efficiency. The idea of wave-focusing in a contraction emerged from our work on creating and simulating rogue waves in crossing seas, including a "bore-soliton-splash". Such crossing seas have been recreated and modelled in the laboratory and in simulations by using a geometric channel convergence. The mathematical and numerical modelling is also novel. One monolithic variational principle governs the dynamics including the combined (potential-flow) hydrodynamics, the buoy motion and the power generation, to which the dissipative elements such as the electrical resistance of the circuits, coils and loads have been added a posteriori. The numerical model is a direct and consistent discretisation of this comprehensive variational principle. Preliminary numerical calculations are shown for the case of linearised dynamics; optimisation of efficiency is a target of future work.

Conceptual Design of OWC Wave Energy Converters Combined With Breakwater Structures

2010 ◽  
Author(s):  
Vallam Sundar ◽  
Torgeir Moan ◽  
Jo̸rgen Hals
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
Floating Bodies ◽  
Energy Device ◽  
Energy Devices ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Caisson Breakwater ◽  
Perforated Caisson ◽  
Energy Converters

Ocean wave energy is one of several renewable sources of energy found in the ocean. The energy in the oscillatory ocean waves can be used to drive a machinery that converts the energy to other forms. Depending on the type and their location with respect the coast and offshore, a number of devices have been and are being developed to extract the wave energy for conversion into electricity. The most common devices are referred to as the oscillating water column (OWC), hinged contour device, buoyant moored device, hinged flap and overtopping device. Particularly popular are OWCs and moored floating bodies. The idea of integrating breakwater and wave energy converters emerged in the Indian wave energy program. Graw (1996) discussed this idea and pointed out the advantage of shared costs between the breakwater and the wave energy device. Because long waves are usually experience stronger reflection at coasts and breakwaters, they provide good conditions for the operation wave energy devices which work efficiently when the reflection is high. There are examples that OWC devices have been installed in water as shallow as 3 m. This paper reviews the options of integrating OWCs with different kinds of breakwaters like the perforated or non-perforated caisson breakwater, and non-gravity piled and floating types. The purpose of each of the concepts will also be highlighted.

Monitor the Impact of Marine Renewable Energy Devices on Local Environment

2013 ◽  
Vol 448-453 ◽  
pp. 1620-1623
Author(s):  
Jia Liu ◽  
Feng Xu ◽  
Xu Dong An ◽  
Qiao Zhang ◽  
Juan Yang
Keyword(s):  
Renewable Energy ◽  
Local Environment ◽  
Global Scale ◽  
Energy Device ◽  
Energy Devices ◽  
Marine Renewable Energy ◽  
Underwater Environment ◽  
Marine Energy ◽  
Development And Utilization ◽  
The Impact

The development and utilization of clean and renewable marine energy sources will be a way for the development of economy. Although on a global scale the advantages of renewable energy are not in doubt, the impacts on the local environment must be carefully considered. The sonar devices could be used to monitor the underwater environment around the marine renewable energy device. In this paper, a Multi-beam Echo Sounder is introduced. And the measured results in a lake are given, which are shown that this sonar could detection the fish effectively.

A Wave Power Device Based on the Principle of the Connecting Rod’s Transmission

2014 ◽  
Vol 915-916 ◽  
pp. 381-384
Author(s):  
Guo Liang Zhu ◽  
Yan Jun Zhang ◽  
Feng Zhu
Keyword(s):  
Wave Energy ◽  
Tidal Energy ◽  
Energy System ◽  
Energy Structure ◽  
Energy Devices ◽  
Energy Technologies ◽  
World Energy ◽  
New Energy ◽  
Working Principle ◽  
Effective Use

The current structure of the world energy system is in transition, the traditional methods have been unable to meet human's requirements to energy, and the collection and utilization of new energy sources have become a very promising research directions, such as solar energy, tidal energy, wind energy, etc. China's energy structure exists many problems; therefore we must vigorously develop renewable energy technologies. This article briefly discusses the issues of China's energy structure and the potential of wave energy, also introduces an effective use of sea wave energy devices, and analyses its structure, working principle and efficiency.

scholarly journals A Nonlinear Extension for Linear Boundary Element Methods in Wave Energy Device Modelling

2012 ◽  
Author(s):  
Alexis Merigaud ◽  
Jean-Christophe Gilloteaux ◽  
John V. Ringwood
Keyword(s):  
Boundary Element ◽  
Wave Energy ◽  
Linear Models ◽  
Boundary Element Methods ◽  
Hydrodynamic Models ◽  
Energy Device ◽  
Energy Capture ◽  
Energy Devices ◽  
Higher Order Terms ◽  
Device Modelling

To date, mathematical models for wave energy devices typically follow Cummins equation, with hydrodynamic parameters determined using boundary element methods. The resulting models are, for the vast majority of cases, linear, which has advantages for ease of computation and a basis for control design to maximise energy capture. While these linear models have attractive properties, the assumptions under which linearity is valid are restrictive. In particular, the assumption of small movements about an equilibrium point, so that higher order terms are not significant, needs some scrutiny. While this assumption is reasonable in many applications, in wave energy the main objective is to exaggerate the movement of the device through resonance, so that energy capture can be maximised. This paper examines the value of adding specific nonlinear terms to hydrodynamic models for wave energy devices, to improve the validity of such models across the full operational spectrum.

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