Search results for "Offshore"
showing 10 items of 110 documents
Introduction of Offshore Wave, Wind and Solar Energies in Vietnam
2020
In Vietnam, the energy demand shows an ever-increasing trend. To limit the utilization of fossil fuels and the following consequences for the environment, renewable energy sources must be adopted. In this context, the paper assesses the utilization of offshore wind and sea wave, by considering a commercial wind turbine and a prototypical wave energy converter. Solar energy can be optionally also collected by this device. An algorithm is introduced to find the best composition of the three sources able to cover a desired share of energy demand. The approach is applied to Ca Mau, a province in the southern part of Vietnam. Finally, the results encourage the adoption of these energy sources th…
Smart grid for offshore wind farms: Towards an information model based on the IEC 61400-25 standard
2012
Nowadays, wind energy is one of the most recognized renewable energy sources. Onshore wind farms have been built in many countries, such as Denmark, Norway, UK, Italy, Brazil and the US. To utilize the more stable wind resources, wind farms have moved off the shore, first to shallow waters near shore and now extending to deeper waters and far off the shore. Deep-water offshore solutions will give access to large areas with high wind, and less sensitivity to noise, visual impacts and size. However, the cost of developing and operating an offshore wind farm is many times larger than onshore due to large water depths and harsh offshore environments. Hence, the needs for fast and automatic data…
Effect of Wind Turbulence on Extreme Load Analysis of an Offshore Wind Turbine
2019
Abstract Evaluation of dynamic responses under extreme environmental conditions is important for the structural design of offshore wind turbines. Previously, a modified environmental contour method has been proposed to estimate extreme responses. In the method, the joint distribution of environmental variables near the cut-out wind speed is used to derive the critical environmental conditions for a specified return period, and the turbulence intensity (TI) of wind is assumed to be a deterministic value. To address more realistic wind conditions, this paper considers the turbulence intensity as a stochastic variable and investigates the impact on the modified environmental contour. Aerodynam…
Aquaculture in Sicily: the state of the art
2009
Aquaculture in Sicily, represented almost exclusively by seabass and sea bream production, together with capture fishery, plays a significant role in the regional economy. On a national basis, the regional production covers about 20% of Italian euryha- line fish production. Fingerling supply is guaranteed by the two hatcheries present on the Island. Twelve floating cage farms and two inshore farms annually produce about 4,000 t of fish. A small extensive production arises from the storage basins of the salt work of Trapani. This niche production could represent an opportunity to realize a new distinctive organic aquaculture, preferred by the consumers respect to intensive produced fish, tha…
Europe's offshore winds assessed with synthetic aperture radar, ASCAT and WRF
2020
Europe's offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of synthetic aperture radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced Scatterometer (ASCAT) ocean wind maps. The wind statistics at 10 and 100 m above mean sea level (a.m.s.l.) height using an extrapolation procedure involving simulated long-term stability over oceans are presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid spacing with data …
Europe’s offshore winds assessed from SAR, ASCAT and WRF
2019
Abstract. Europe’s offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of Synthetic Aperture Radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced SCATterometer (ASCAT) ocean wind maps. The wind statistics at 10m and 100m height using an extrapolation procedure involving simulated long-term stability over oceans is presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid resolution with data every 30 minutes during 30 years f…
Extended Environmental Contour Methods for Long-Term Extreme Response Analysis of Offshore Wind Turbines1
2020
Abstract Environmental contour method is an efficient method for predicting the long-term extreme response of offshore structures. The traditional environmental contour is obtained using the joint distribution of mean wind speed, significant wave height, and spectral peak period. To improve the accuracy of traditional environmental contour method, a modified method was proposed considering the non-monotonic aerodynamic behavior of offshore wind turbines. Still, the modified method assumes constant wind turbulence intensity. In this paper, we extend the existing environmental contour methods by considering the wind turbulence intensity as a stochastic variable. The 50-year extreme responses …
IT-sikkerhetspolicy for Integrerte operasjoner
2007
Masteroppgave i informasjons- og kommunikasjonsteknologi 2007 – Høgskolen i Agder, Grimstad Ved å benytte IKT i alle ledd i oljeindustrien, vil man oppnå hurtigere og bedre beslutninger, og med hjelp av sanntidsdata kan man integrere arbeidsprosesser på tvers av fag og mellom organisasjoner. Denne utviklingen blir i oljenæringen kalt Integrerte operasjoner (IO). Ved hjelp av IO kan operasjoner styres uavhengig av avstand og geografisk lokasjon. Det er satt inn store ressurser på dette feltet, og allerede i dag ser man vellykkede implementeringer av Integrerte operasjoner. Med Internett som en del av bærenettverket for data produsert i oljenæringen, vil trafikken i utgangspunktet være svært …
Semiactive vibration control of offshore wind turbine towers with tuned liquid column dampers using H<inf>&#x221E;</inf> output feedb…
2010
This short paper addresses the problem of vibration in wind turbine towers. These structures are subject to winds and waves causing undesirable vibrations that affect the structure integrity and system performance. In order to mitigate the vibrations of the tower, a controllable tuned liquid column damper is placed on its top. We propose the use of H ∞ control techniques to formulate a control law. Furthermore, the controller uses output feedback to avoid the dependence on the knowledge of the states of the system. Simulation results illustrate the design procedure proposed in this paper.
Numerical and analytical analysis of a monopile-supported offshore wind turbine under ship impacts
2021
Abstract Offshore wind turbines in the vicinity of ship traffic are exposed to increased risks of ship collisions. To better understand the impact mechanism, this paper evaluates the dynamic responses of a monopile-supported wind turbine under ship impacts, using both numerical and analytical methods. The nonlinear finite element method is applied during the numerical simulations, and the wind load effects, soil conditions, and rigid and deformable ship bows are considered. The analytical approach, originally developed based on the energy method, is extended here to address the damping effects of monopile-supported wind turbines. In the case study, the impacts are studied between a 4600-ton…