New Spar Design for Floating Offshore Wind Turbine With Damping Plates

Author(s):  
Shigesuke Ishida ◽  
Yasutaka Imai

Abstract Spar is one of the promising floating structures which support wind turbine at sea. In general, some lower part of spar is used as a ballast tank. It is possible to replace this part with other shapes without water-tightness because this part does not contribute to buoyancy nor stability to support the weight or heeling moment of wind turbine. In the field of oil and gas production, truss spar has been developed with this concept and the lower part consists of heave plates. However, for wind turbine, pitching motion is more important than heaving. The authors changed this part to four vertical damping plates to reduce this motion. The effect of the central gap and holes in the damping plates were investigated because these parameters have effects on flow separation and hydrodynamic forces. The motions in waves of the new spars were compared with a classic spar of the same dimensions and stability. The proposed vertical damping plates, with central gap or holes, work to reduce the pitching motion in wide range of wave frequency. Considering the expected cost reduction and some motion reduction, the promising nature of the proposed spar revealed.

2009 ◽  
Vol 364 (1526) ◽  
pp. 2115-2126 ◽  
Author(s):  
Jefferson Hopewell ◽  
Robert Dvorak ◽  
Edward Kosior

Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it may be possible to divert the majority of plastic waste from landfills to recycling over the next decades.


2019 ◽  
Vol 12 (3) ◽  
pp. 46-57 ◽  
Author(s):  
S. V. Kazantsev

The article presents the results of the author’s research of the impact of a wide range of restrictions and prohibitions applied to theRussian Federation, used by a number of countries for their geopolitical purposes and as a means of competition. The object of study was the impact of anti-Russian sanctions on the development of Oil & Gas industry and defence industry complex ofRussiain 2014–2016. The purpose of the analysis was to assess the impact of sanctions on the volume of oil and gas production, the dynamics of foreign earnings from the export of oil and gas, and of foreign earnings from the sale abroad of military and civilian products of the Russian defence industry complex (DIC). As the research method, the author used the economic analysis of the time series of statistical data presented in open statistics and literature. The author showed that some countries use the anti-Russian sanctions as a means of political, financial, economic, scientific, and technological struggle with the leadership ofRussiaand Russian economic entities. It is noteworthy that their introduction in 2014 coincided with the readiness of theUSto export gas and oil, which required a niche in the international energy market. The imposed sanctions have affected the volume of oil production inRussia, which was one of the factors of reduction of foreign earnings from the country’s oil and gas exports. However, the Russian defence industry complex has relatively well experienced the negative impact of sanctions and other non-market instruments of competition


Author(s):  
Robert E. Sheppard ◽  
Frank J. Puskar

With the expected introduction of wind turbine facilities for the generation of electricity to the US Offshore Continental Shelf (OCS) waters, there is a need to evaluate how the long term operations of these facilities can be ensured through Integrity Management (IM) activities, particularly inspections. There is a long operational history of IM in the Gulf of Mexico, offshore California and Alaska, and around the world for fixed and floating oil and gas platforms for drilling and production. Both prescriptive and Risk-Based Inspection (RBI) methodologies have been established and implemented to direct inspection operations for these facilities. This experience provides a foundation for implementing similar Integrity Management programs for offshore wind turbine structures. Through the incorporation of existing guidance for subsea structures, above-water structures and access systems along with guidance from subject matter experts regarding critical inspection areas, inspection techniques, and inspection intervals, a guidance document has been developed which includes regional variations that address unique operating conditions in US waters. This work was funded by the US Department of the Interior, Minerals Management Service (MMS).


Author(s):  
Jakob Wedel-Heinen ◽  
Knut O. Ronold ◽  
Peter Hauge Madsen

The first DNV-OS-J101 standard “Design of Offshore Wind Turbine Structures” [1] was issued in June 2004. The standard represented a condensation of all relevant requirements in DNV standards for the offshore oil and gas industry which were considered relevant also for offshore wind turbine structures, supplemented by necessary adaptation to the wind turbine application. Det Norske Veritas (DNV) plans to issue the next revision of DNV-OS-J101 [2] in 2007. The DNV revised standard now implements the requirements of the coming IEC 61400-3 standard [11], which was presented as a committee draft in 2006. Numerous practical guidelines have been included to help designers of offshore wind turbine structures to develop cost optimal designs. The present paper summarises the proposed revisions of DNV-OS-J101 [2]. The most important revisions cover new formulations for design load cases, modified partial safety factors, exclusion of transformer platforms, more information on wave loads in shallow water and a revised chapter for design of concrete structures.


2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Hannah L. Allen ◽  
Andrew J. Goupee ◽  
Anthony M. Viselli ◽  
Christopher K. Allen ◽  
Habib J. Dagher

Abstract Floating offshore wind turbine (FOWT) hull technologies are evolving rapidly with many technically viable designs. However, a commercially dominant architecture has yet to emerge. Early hull designs including semisubmersible, spar, and tension leg platforms were largely derived from offshore oil and gas technologies, but recent developments in the commercial application and optimization of FOWTs have resulted in a number of unique, FOWT-specific hull configurations. One hull design of interest includes the application of a moonpool to aid in mitigating platform motion in the presence of waves. A version of this annular hull has been deployed in France and Japan. In this paper, a 6-MW version of an annular hull is studied through experimental model testing and numerical analysis. The primary portion of this work involves testing a 1/100th-scale model in the Harold Alfond Wind Wave Ocean Engineering Laboratory at the University of Maine. A secondary component of this work investigates the capability of ANSYS aqwa, a typical commercial hydrodynamic software, to recreate the wave-induced motion of a FOWT hull containing a moonpool. An additional secondary component of this study compares the wave-only performance of the annular hull to experimental data obtained for the DeepCwind semisubmersible, spar, and tension leg platform to provide context for the measured response. The results obtained show that ANSYS aqwa can adequately predict the gross response of the annular hull motion and that the moonpool design tested often exhibits greater motion than the systems tested during the DeepCwind campaign.


2005 ◽  
Vol 29 (5) ◽  
pp. 463-469 ◽  
Author(s):  
Anders Moller

In the oil and gas industry, the foundations of offshore platforms have, for decades, used the grouted technique. This technology has now been transferred into the offshore wind turbine industry. This paper gives details of the use of the technology in some of the first offshore windfarms in Europe and considers future design possibilities.


Author(s):  
Raul Urbina ◽  
James M. Newton ◽  
Matthew P. Cameron ◽  
Richard W. Kimball ◽  
Andrew J. Goupee ◽  
...  

Environmental conditions created by winds blowing oblique to the direction of the waves are necessary to conduct some survivability tests of offshore wind turbines. However, some facilities lack the capability to generate quality waves at a wide range of angles. Thus, having a wind generation system that can be rotated makes generating winds that blow oblique to the waves possible during survivability tests. Rotating the wind generation system may disrupt the flow generated by the fans because of the effect of adjacent walls. Closed or semiclosed wind tunnels may eliminate the issue of wall effects, but these types of wind tunnels could be difficult to position within a wave basin. In this work, a prototype wind generation system that can be adapted for offshore wind turbine testing is investigated. The wind generation system presented in this work has a return that minimizes the effect that the walls could potentially have on the fans. This study characterizes the configuration of a wind generation system using measurements of the velocity field, detailing mean velocities, flow directionality, and turbulence intensities. Measurements were taken downstream to evaluate the expected area of turbine operation and the shear zone. The dataset has aided in the identification of conditions that could potentially prevent the production of the desired flows. Therefore, this work provides a useful dataset that could be used in the design of wind generation systems and in the evaluation of the benefits of recirculating wind generation systems for offshore wind turbine research.


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