Monthly Archives: January 2012

Overview of the Alternative Topologies of Linear Generators in Wave Energy Conversion Systems


PE Kakosimos, EM Tsampouris, NM Kimoulakis AG Kladas – Materials Science Forum, 2012

Abstract
 Several operation principles and generator types have been developed because of the growing interest for the wave energy conversion systems (WECSs). A WECS is demanded to be more efficient so that the overview of the already developed systems is necessary. An overview of the different operation principles and the various linear generator types is presented analyzing the advantages and the disadvantages. Finally, a complete scheme gathering the most vital characteristics is introduced.

Link

Advertisements

Leave a comment

Filed under Component Development, System Development

Assessing wave energy effects on biodiversity:the Wave Hub experience


MJ Witt, S Bearhop, AC Broderick, DJ Hodgson, R Inger, BJ Godley, EV Sheehan, DC Conley, SP Cotterell, WJ Grecian, P Hosegood, DW Sims, RC Thompson, SC Votier, MJ Attrill, E Crow, C Halsband, PI Miller, and K Vanstaen- Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2012

Abstract
Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects—both positive and negative.

Link

Leave a comment

Filed under Resource Characterization

OffshoreGrid: Techno-Economic Model for Future Offshore Electricity Transmission


P Kreutzkamp, J De Decker, N Picot 2012

Summary
This project investigated the most beneficial wind farm connection concepts for 126 GW in 321 offshore wind farms as expected for the year 2030. Based on this two highly efficient offshore grid designs were developed with modular building stones such as direct interconnectors, hub-to-hub connections, Tee-in solutions.

Link

Leave a comment

Filed under Economics

Wave energy: a Pacific perspective


R Paasch, K Ruehl, J Hovland, S Meicke – Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, January 2012

Abstract
This paper illustrates the status of wave energy development in Pacific rim countries by characterizing the available resource and introducing the region’s current and potential future leaders in wave energy converter development. It also describes the existing licensing and permitting process as well as potential environmental concerns. Capabilities of Pacific Ocean testing facilities are described in addition to the region’s vision of the future of wave energy.

Link

Leave a comment

Filed under Sector Overview

Microbial Corrosion Resistance of Stainless Steels for Marine Energy Installations


LL Machuca, SI Bailey R Gubner – Advanced Materials Research, 2012

Abstract
A range of stainless steels has been investigated for resistance to microbiologically influenced corrosion in seawater. The corrosion potential was monitored for stainless steel coupons exposed to sterilized seawater and to microbiologically active seawater, which showed the effect of the growth of microorganisms. Cyclic potentiodynamic polarization scans confirmed that 13%Cr stainless steel is very susceptible to localized corrosion under these conditions. 316L stainless steel was also quite susceptible to localized corrosion, whereas 2205 duplex stainless displayed good resistance to localized corrosion. Naturally occurring microorganisms in the seawater were shown to exacerbate the localized corrosion.

Link

Leave a comment

Filed under Materials and coatings

Determinants of Renewable Energy Innovation: environmental policies vs. market regulation


F Vona, F Nicolli, L Nesta – 2012

Abstract
This paper carries out a comprehensive analysis of renewable energy innovations considering four mechanisms suggested by innovation models: 1. policy-inducement; 2. market structure; 3. demand and social cohesion-mainly proxied by income inequality; 4. characteristics of country knowledge base. For OECD countries and years 1970-2005, we build a unique dataset containing time-varying information on quality-adjusted patent production in renewable energy, the latter being a function of environmental policies, green R&D, entry barriers, knowledge stock, knowledge diversity and income inequality. We develop count data models using the Generalized Method of Moments (GMM) to account for endogeneity of policy support. Our synthetic policy index positively affects innovations especially in countries with deregulated energy markets and low entry barriers. The effect of entry barriers and inequality is negative and of similar magnitude as that of policy. Product market liberalization positively affects green patent generation, especially so when ambitious policies are adopted, when the initial level of public R&D expenditures and when the initial share of distributed energy generation is high. Our results are robust to alternative specifications, to the inclusion of technology-specific effects and to the use of quality-adjusted patents as dependent variables. In the latter case, the estimated effect of lowering entry barriers and of knowledge diversity almost double on citation count relatively to patent count.

Link

Leave a comment

Filed under other Cross cutting, other RD&D, Standards and Protocols

A Novel Design of Wave Energy Harvest Device with Flywheel Energy Storage System


K Lin, YH Joo, S Helkin C Ham

Abstract
This paper describes a novel design of a wave energy harvest device that utilizes a flywheel energy storage (FES) system to yield increased power generation.  The buoy design is moored to the ocean floor via a cable; as the buoy is heaved vertically by ocean waves, the cable rotates a pulley which in turn drives the rotor of an onboard generator.  A ratchet within the pulley allows the rotor to only be turned in one direction.  To prevent large tensions from begin imposed on the cable by the back torque from the generator, a flywheel energy storage system is used. As the buoy is heaved vertically by incident waves, the electric load on the generator is removed, resulting in all of the energy extracted by the buoy to be stored in the flywheel system.  Consequently the buoy is less restricted by high tensions and able to closely follow the motion of the waves, even while using a large generator with a high back torque coefficient.  As the buoy moves downward after being heaved, the load is re-coupled to the generator, transferring the energy stored by the flywheel to the generator.  Essentially the FES system trades power generation time for improved buoy motion.  The focus of the paper is not to optimize the design of the buoy, but rather demonstrate the effectiveness of the FES system for the buoy design with arbitrary parameters.  Simple simulations for a small buoy confirm the effectiveness of the proposed flywheel energy storage system—without it the wave energy harvest device produced only 90.0watts of power, but with it the device produced 180.3watts—an improvement of 100%. This improvement is based on a small generator with low back torque coefficient; for a large-scale design and stronger generator, the benefits are expected to be even greater.

Link

Leave a comment

Filed under Component Development, Modeling

Design and Stability of a Floating Free Stream Energy Converter


WMJ Batten, F Weichbrodt, GU Muller, J Hadler, C Semlow, M Hochbaum, S Dimke, P Frohle- Proceedings of the 34th World Congress of the International Association for Hydro- Environment Research and Engineering

Abstract
A floating energy converter to extract kinetic energy from river and sheltered tidal sites has been developed and tested. The energy converter has a floating body with side pontoons, base plate and separators that drives a hydrostatic pressure wheel. This paper compares results from floating lab scale models 1.2m in length with 0.5m diameter wheel tested in a circulating water channel with a 7.6m long demonstrator towed in an estuary. The power and stability scaling of the models are assessed and the results are used to predict performance of larger devices to assess potential in remote areas.

Link

Leave a comment

Filed under System Development

A Combined Multi-Site and Multi-Device Decision Support System for Tidal In-Stream Energy


M Abundo, A Nerves, E Paringit, C Villanoy – Energy Procedia, 2012

Abstract
This paper combines site and device suitability approaches into one framework to assist stakeholders in identifying locations fit for Tidal In-Stream Energy (TISE) extraction as well as nominating devices that are matched to the conditions of those locations. A Matlab-based decision support system is developed using the framework. Site-Device matching is performed considering resource data, device power generation, energy production, and cost. A case study, involving four sites in the Philippines, is presented. Hydrodynamic simulations using DELFT3D are done. The suitability of modeled TISE conversion devices is investigated over several locations in the case study. Device nominations are made for respective locations using highest energy production as dominating criterion.

Link

 

Leave a comment

Filed under Modeling

Dynamic analysis method of offshore jack-up platforms in regular and random waves


H Yu, X Li, S Yang, Journal of Marine Science and Application, 2012

Abstract
A jack-up platform, with its particular structure, showed obvious dynamic characteristics under complex environmental loads in extreme conditions. In this paper, taking a simplified 3-D finite element dynamic model in extreme storm conditions as research object, a transient dynamic analysis method was proposed, which was under both regular and irregular wave loads. The steps of dynamic analysis under extreme conditions were illustrated with an applied case, and the dynamic amplification factor (DAF) was calculated for each response parameter of base shear, overturning moment and hull sway. Finally, the structural response results of dynamic and static were compared and analyzed. The results indicated that the static strength analysis of the Jack-up Platforms was not enough under the dynamic loads including wave and current, further dynamic response analysis considering both computational efficiency and accuracy was necessary.

Link

Leave a comment

Filed under Modeling