Category Archives: Standards and Protocols

Uncertainties in the design of support structures and foundations for offshore wind turbines


Vicente Negro, José-Santos López-Gutiérrez, M. Dolores Esteban, and Clara Matutano – Renewable Energy, March 2014

Abstract

Offshore wind industry has exponentially grown in the last years. Despite this growth, there are still many uncertainties in this field. This paper analyzes some current uncertainties in the offshore wind market, with the aim of going one step further in the development of this sector. To do this, some already identified uncertainties compromising offshore wind farm structural design have been identified and described in the paper. Examples of these identified uncertainties are the design of the transition piece and the difficulties for the soil properties characterization. Continue reading

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Non-dimensional scaling of tidal stream turbines


Mason-Jones, A., O’Doherty, D. M., Morris, C. E., O’Doherty, T., Byrne, C. B., Prickett, P. W., R.I Grovenor, I. Owen, S. Tedds, R.J. Poole, R. J. – Energy, August, 2012
Abstract
The impact of local depth-wise velocity profiles on tidal turbine performance is important. Although the use of standard power laws for predicting velocity profiles is common, these laws may underestimate the magnitude of the depth-wise velocity shear and power attenuation. Predicting the performance of a tidal turbine in a high velocity shear is crucial in terms of power extraction. This paper discusses the dimensional scaling of a turbine using CFD and experimental data. Key performance characteristics (power, torque and thrust coefficients) were studies with increasing diameters and velocities, by generating. a series of non-dimensional curves. This provides a first order approximation for matching turbine performance characteristics to site conditions. The paper also shows that the use of a volume-averaged velocity derived from the upstream velocity profile can be used to determine these key performance characteristics. These are within 2% of those determined assuming a uniform flow. The paper also shows that even changes in the blade pitch angle results in new turbine characteristics under uniform velocity conditions and it is expected that these can be used for profiled flow.

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In-Stream Tidal Power: A Literature Review


CP Kuang, XT Zhao, Y Pan, J Gu – Advanced Materials Research, May 2012

Abstract
Under the energy crisis, the development of new energy has become one of the top issues for countries in the world. In-stream tidal power is a young generation technology to exploit the tidal energy, whose potential has been attached great importance to by many countries. Turbine is the core components of the in-stream tidal power generation system. In this paper the relatively mature technology is summarized extensively. Recent years many countries have pay a lot of attentions to in-stream tidal power and set the future development goals. For both the development stage and installed capacity China have a larger gap with western foreign, but the research of the in-stream tidal power device in China already has made great progress, and the development of in-stream tidal power generation technologies has show great advantages in the protection of the environment, sustainable development of economic and social and mitigation of the energy crisis.

 

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US Offshore Wind Energy-Standards and Third Party Oversight


D Wisch – Offshore Technology Conference, May 2012

Abstract
The Bureau of Offshore Energy Management, Regulation and Enforcement (BOEMRE), subsequently reorganized into Bureau of Safety and Environmental Enforcement (BSEE) and Bureau of Ocean Energy Management (BOEM), part of the US Department of the Interior, had been given responsibility as the lead agency in the regulatory process for offshore wind energy. In developing the framework and requirements, BOEMRE has drawn heavily on previous experience as the lead agency for the offshore oil and gas industry in addition to reviewing land based practices and practices in other countries.

In 2010, BOEMRE asked the National Research Council (NRC) Marine Board to review the BOEMRE approach utilizing third parties to review aspects of the design, fabrication and installation of offshore wind energy facilities. BOEMRE commissioned the Marine Board to perform a study to assess the potential. The study scope was limited to structural safety and to aspects of structural safety during operations that could be affected during design, fabrication and installation.

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Offshore wave energy generation devices: Impacts on ocean bio-environment


L Lin, H Yu- Acta Ecologica Sinica, May 2012

Abstract
This article discusses several aspects, including influence of offshore WEGs on marine macrofaunal communities, interactions between offshore WEGs and biofouling organisms, impacts of offshore WEGs on marine birds and of electromagnetic fields (EMFs) on marine animals as well as “artificial reef” effects.

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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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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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Are Nearly all Tidal Stream Turbines Designs Wrong?


S Salter-Oxford Tidal Energy Workshop, March 2012

Summary
There were many possible options for onshore wind turbines but the three-bladed axialflow horizontal-axis design with a mono-tube tower is now universal. It is therefore not surprising that nearly all of the proposals for tidal-stream turbines use horizontal-axis axial-flow. The widely separated rotors are the equivalent of leaky pipes in a hydro-electric scheme. This paper attempts to show that, despite its widespread popularity, the transfer from wind technology is wrong and that a cross-flow design [1] with rotation about a vertical axis [2] is better.

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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.

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Research for the Sustainable Development of Tidal Power in Maine


T Johnson, GB Zydlewski- Maine Policy Review Winter/Spring 2012

Summary
Generating electricity from Maine’s substantial tides has been a dream for generations. Today, as Teresa Johnson and Gayle Zydlewski describe, the state is poised for a new era in sustainable tidal-power development.A pilot project is already underway in the Cobscook Bay/Western Passage area near Eastport and Lubec. Tidal-power development presents technical, environmental, and social challenges, however, and the authors discuss how the Maine Tidal Power Initiative is working to develop a cooperative framework that integrates stakeholders, developers, and policymakers to tackle some of these challenges.

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