Monthly Archives: April 2012

Environmentally Benign and Permanent Modifications to Prevent Biofouling on Marine and Hydrokinetic Devices


Z. Zhang – Technical Report submitted to DOE EERE Wind & Water Power Program, April 2012

Abstract

Semprus Biosciences is developing environmentally benign and permanent modifications to prevent biofouling on Marine and Hydrokinetic (MHK) devices. Biofouling, including growth on external surfaces by bacteria, algae, barnacles, mussels, and other marine organisms, accumulate quickly on MHK devices, causing mechanical wear and changes in performance. Biofouling on crucial components of hydrokinetic devices, such as rotors, generators, and turbines, imposes substantial mass and hydrodynamic loading with associated efficiency loss and maintenance costs. Most antifouling coatings leach toxic ingredients, such as copper and tributyltin, through an eroding process, but increasingly stringent regulation of biocides has led to interest in the development of non-biocidal technologies to control fouling. Semprus Biosciences research team is developing modifications to prevent fouling from a broad spectrum of organisms on devices of all shapes, sizes, and materials for the life of the product. The research team designed and developed betaine-based polymers as novel underwater coatings to resist the attachment of marine organisms. Continue reading

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Filed under Materials and coatings

Study on the marine growth effect on the dynamic response of offshore wind turbines


W Shi, HC Park, JH Baek, CW Kim, YC Kim, HK Shin – International Journal of Precision Engineering and Manufacturing, April 2012

Abstract
Jacket foundation is regarded as a suitable solution for wind turbines in the intermediate water depths ranging from 30 to 80 m. Numerous types of marine fouling organisms may be found on the submerged members of jacket. Marine growth is found to influence loading of offshore structures by increasing tube diameters, drag coefficient, mass and hydrodynamic added mass and structural weight. In this paper, the types and distribution of marine growth are mentioned. We aimed to investigate the effects of marine growth with different thicknesses, densities and hydrodynamic coefficients values on characteristics of an offshore wind turbine with jacket foundation. The eigen analysis shows that the marine growth has a little effect on the first order natural frequencies while it has higher effect on second and third order natural frequencies of the support structure. Thickness and density have a strong effect on hydrodynamic loads. To obtain the properties of marine growth and hydrodynamic coefficients in the design of offshore wind turbines, full-scale measurements are needed.

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Cost-Benefit Analysis of Tidal Energy Generation In Nova Scotia: A Scenario For A Tidal Farm With 300mw of Installed Capacity In The Minas Passage In 2020


J Houde – Dalhousie University Master’s Thesis, April 2012

Abstract
This thesis presents a cost-benefit analysis of tidal power generation with specific reference to the installation of a 300MW tidal farm in the Minas Passage, in Nova Scotia, in 2020, as a case study. Nova Scotia has set aggressive targets to increase the share of renewables in the province’s electricity generation mix and tidal energy is considered to be the ―sleeping giant‖ amongst renewable energy sources. After having estimated the many costs and benefits and having calculated the net present value of such a project, it is concluded here that the project should not proceed as its costs greatly surpass its benefits. However, it is recommended that further studies evaluating the costs and benefits at different levels of tidal penetration be conducted for the province.

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Filed under Economics

A Methodology for Large-Scale Ocean Wave Power Time-Series Generation


TKA Brekken, HT Ozkan-Haller, A Simmons- IEEE Journal of Oceanic Engineering, April 2012

Abstract
Ocean wave power is characterized by high power density, and wave forecasts can predict incident wave energy days in advance. These qualities make ocean wave power a promising renewable energy source. In the near future, utility-scale wave energy conversion arrays will likely be installed. However, little is currently known on the impact of large wave energy conversion (WEC) facilities on utility operation and planning. In this paper, a methodology is developed for generating WEC array power time series that can be used for wave power utility integration purposes. Sample results show that the methodology produces first-order approximations of WEC array outputs and demonstrate that significant smoothing of the total wave power output from an array can be expected.

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Disruption to benthic habitats by moorings of wave energy installations: A modelling case study and implications for overall ecosystem functioning


V Krivtsov, B Linfoot – Ecological Modeling, April 2012

Highlights
► OrcaFlex and a Matlab script was used to simulate a WEC and the resulting disturbance of bottom sediments. ► Simulations were performed for regular and irregular wave regimes. ► This is the first published estimate of the affected area of benthic habitats. ► Sediment erosion by mooring lines will effect a whole range of ecosystem processes. ► These issues are important in calculations of ecological risks of any moored objects.

 

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Filed under Modeling, Standards and Protocols

2010 Cost of Wind Energy


S Tegen, M Hand, B Maples, E Lantz, P Schwabe, A Smith – NREL, April 2012

Summary
This report presents the best available information on the cost of wind energy in 2010, along with a summary of historical trends and future projections. One way to express the cost of wind energy is to calculate the levelized cost of energy (LCOE). The LCOE is a metric that has been used by the U.S. Department of Energy (DOE) for many years to evaluate the life-cycle costs of generation for energy projects and the total system impact of technology design changes.

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Filed under Economics, Wind

Accelerating the development of marine energy: Exploring the prospects, benefits and challenges


H Jeffrey, B Jay, M Winskel – Technological Forecasting and Social Change, April 2012

Highlights
► Accelerated development of marine energy impacts UK energy system decarbonisation. ► Realising the accelerated marine energy scenario will require sustained support. ► Innovation support for marine energy has changed over time due to policy learning. ► Marine acceleration requires a co-evolution of development and deployment.

 

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Filed under Economics

The Design and Optimization for The Dome of Tidal Turbine


H Lu, Y Li, L Ma, X Pao – Energy Procedia, April 2012

Abstract
This paper uses Diffuser Augmented Wind Turbine for reference. According to the characteristics of ocean current movement, this paper gives several dome model programs for the straight blade vertical-axis tidal turbine. Make use of it to increase its output power. This paper gives several dome model programs for the straight blade vertical-axis tidal turbine. And optimum scheme is chosen by numerical simulation.

 

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Condition monitoring of wind turbines: Techniques and methods


FPG Márquez, AM Tobias, JMP Pérez, M Papaelias- Renewable Energy, October 2012

Highlights
► This paper provides a review of the state-of-the-art in the CM of wind turbines. ► It describes the different maintenance strategies, CM techniques and methods. ► It is highlighted the various combinations of these reported in the literature. ► Future research opportunities in fault diagnostics are identified using a qualitative FTA.

 

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Filed under Standards and Protocols

Development of a free vortex wake method code for offshore floating wind turbines


T Sebastian, MA Lackner- Renewable Energy, October 2012

Highlights
► Developed and tested a free vortex model code (WInDS) for future study of offshore floating wind turbine aerodynamics. ► Described the theory and implementation of the code. ► Validated using test cases, both analytical and experimental. ► WInDS demonstrated robust properties necessary for floating wind turbine simulations.

 

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Filed under Modeling