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Power Industry
This article presents the recent developments in offshore wind energy. The focus is put on the history, the actual situation and the future developments for the structural design and for the European wind market. Typical offshore foundation structures and details are shown in examples in order to identify the specific considerations necessary for offshore wind farm design. INTRODUCTION Due to the world's rising energy consumption, the limited existence of fossil energy sources and last but not least the dramatic changes of the world climate, attention has been drawn to the extension of renewable energy. Among the various fields of renewable energy sources, the wind energy sector has grown significantly within the last two decades. Especially Denmark and Germany started with small turbines of 20โ50 kW (Fig. 1). Today, serial production of commercially available wind turbines has reached a size of up to 6 MW. The large machines are being developed principally through the drive to take the technology offshore. Parallel to the increase in turbine size, the number of installed turbines and the number of countries that support wind energy have continuously increased, resulting in an exponential growth of the installed capacity. According to recent studies, the installed capacity of wind turbines in Europe totals 48,000 MW at the end of 2006. In 2010 approx. 88,000 MW are expected, the expected output of that is comparable to the output of 20 large nuclear power plants. Europe, Asia and the Americas will be the growing markets of the near future. HISTORY AND ACTUAL SITUATION The development of the industrial wind energy usage in Germany started with a set-back. The ambitious research turbine GROWIAN (GROsse WIndenergie ANlage) (Fig. 2) in Kaiser-Wilhelm-Koog at the North Sea Coast (site of WINDTEST Kaiser-Wilhelm-Koog GmbH) has been decommissioned only four years after its first test run onJuly 6, 1983.
To cope with the warming global environment, the hydropower should occupy the attention of the electric power generation system as clean and cool energy sources. In such a situation, the tidal current has scarcely been utilized for the power generation. The authors have proposed and developed a new type of generator with counter-rotating rotors instead of the usual mechanism. This paper discusses the effects of the blade profiles on the hydraulic performances. As a result, the design materials for the solidity of the axial flow runners suitable for the given water circumstances are induced from above discussions. INTRODUCTION To cope with the warming global environment, the hydropower should occupy the attention of the electric power generation system as clean and cool energy sources. In such a situation, the tidal current has scarcely been utilized for the power generation, for instance, the Kanmon Straits in Japan has about 54 MW hydraulic energy. It may be appropriate to apply the high specific speed hydraulic turbine for the tidal power generation. It is also desirable to make the machine compact size and simple composition, but the usual generator may reject such desires. That is, it is necessary, for getting sufficiently the electric power, to make the rotor diameter large or equip with the accelerator such as a gear-box, because the electric power is in proportion to the rotational speed in the magnetic field. Therefore, the authors have proposed and developed a new type of generator with counter-rotating rotors instead of the usual mechanism, which can make the generator diameter small on account of relatively double the rotational speed. Moreover, it is extremely easy to board on the floating buoy moored already in the strait, because the inertia moment of the rotor rotation is counter-balanced successfully (Kanemoto and Tanaka, 2001; Tanaka and Kanemoto, 2004; Kanemoto and Osono, 2004).
- Energy > Renewable > Ocean Energy (1.00)
- Energy > Power Industry (1.00)
A Darrieus-type water turbine using the energy in the local tidal current was developed as energy conversion device for powering a navigation buoy, and the characteristics of the water turbine were observed in a water channel experiment. The energy converter of the electric power generation system was installed in a buoy in a pilot project in the Akashi Strait in Japan. As the result, the changes in generated electric power with current speed were observed. Sufficient energy was obtained from the tidal currents to operate this navigation buoy. INTRODUCTION Operators of navigation beacons have been searching for self-contained energy sources, as it is difficult to supply buoys in the ocean from the commercial power net. Solar and wave-powered renewable energy mechanisms have been developed for navigation buoys (Nakamura, K. 1991). The advantage of tidal currents over other renewable energy sources is they are independent of the weather, so the available power can be calculated. A characteristic of tidal currents in the Akashi Strait is that they reverse direction about every 6 hours, with a sinusoidal variation in speed throughout their cycle. Darrieus-type water turbines are one method for recovering energy from these flows. These were developed in 1931 by the Frenchman Georges-Jean-Marie Darrieus from his original design for wind turbines. The authors have investigated the behavior of Darrieus turbines in water channels to find how to use them as "water wheels" in tidal currents (Shiono, M., Suzuki, K., and Kiho, S. 2002; Shiono, M., Katsuyuki, S., and Seiji, K. 2003). The maximum speed of the tidal currents in the Akashi Strait, where the electric power-generating turbine was located for this study, is about 4 m/s. One provisional estimate of the total annual energy reserves is 13359 TWh (Central Research Institute of Electric Power Industry.1987).
- Energy > Renewable > Ocean Energy (1.00)
- Energy > Power Industry (1.00)
Reliability of the oil discharge operation is an important issue for PETROBRAS (Brazilian oil company) due to the economic impact of a system failure. In this paper, two different cargo oil systems were compared (of "Ataulfo Alves" and "Itabuna" ships), regarding the reliability of the oil discharging operation. Fault trees with the top event "incomplete discharging" were developed, and the reliability was calculated. In this study only the oil transfer system elements were considered. The human reliability effect was neglected, as well as other systems participating in the operation. The reliability database used was the Offshore Reliability Database, known as OREDA (referred to as SINTEF Industrial Management (2002)). When no data was available, other sources were used. The performance of the systems was compared considering weaknesses and strengths of each configuration. The reliability values found were high (above 99 %), but there is room for improvement, especially in the "Ataulfo Alves" system. Adding a flexible back-up pump for the discharging lines could improve the system. INTRODUCTION Comparative reliability studies have been used as a design tool, as reported in several reliability books, such as in Villemeur (1992), particularly in the aeronautical and nuclear fields. Yun et al (2006), for instance, assessed different options for the SMART (an innovative nuclear reactor design) reactor protection system. TRANSPETRO, the oil transport branch of PETROBRAS, operates different types of oil transport ships in its fleet. The most common operation is the transport of oil from the production platforms to terminals located on the Brazilian coast. Therefore, the oil discharging operation reliability of the oil cargo system plays a significant role in the economy of TRANSPETRO. Fig. 1 shows the "Ataulfo Alves" during the oil discharging operation. This study focuses on the cargo oil system of the two types of ships used in this operation: the "Ataulfo Alves" and "Itabuna" classes, calculating the reliability of their systems for one typical discharging operation.
- Energy > Oil & Gas > Upstream (0.48)
- Energy > Power Industry > Utilities > Nuclear (0.48)
- Government > Regional Government > South America Government > Brazil Government (0.45)
A three-dimensional hydrodynamic multi-purpose model for coastal and shelf seas COHERENS is applied to investigate the transport and dispersion of the heated and concentrated brine discharged from the Huangdao Power Plant situated on the western coast of Jiaozhou Bay. The values of time series of current velocity and water surface elevation given by the simulation have a good agreement with observed data. This indicated that the numerical model provided a fair simulation of the coastal flow in Jiaozhou Bay and were thus available for predicting heated and concentrated brine dispersion in the coastal water. The model can be applied to appropriately evaluate the locations of intakes and outlets of the power plants with seawater desalination processes and minimize the adverse influence on the coastal areas. INTRODUCTION Problem Background Seawater desalination has been a solution to water shortages in the field of drinking and industrial matter for several decades. In general, the salt content of water used in industrial production is no more than 0.05โฐ~ 2โฐ. In order to make use of seawater and relieve water shortage, the production of electricity is popularly connected with water. Thus, the power plant and seawater desalination are usually associated with each other, especially in recent years. Even though the processes of seawater desalination contribute to humanity as well as to nature preservation, they are also accompanied adverse environmental effects. However, these effects can be minimized through the appropriate planning. There are high temperature and high salt content in the effluent discharged from seawater desalination processes. The concentrations of the brines are usually found to be double or close to double that of natural seawater. In the case of evaporation methods, thermal pollution is also produced. Although the concentrate from thermal processes such as Multi-Stage Flash Seawater Desalination System (MSF) and Multi Effect Distillation (MED) is typically mixed with cold water prior to discharge, the dilution of concentrate results in a final discharged effluent is still more than the receiving water in temperature and in salinity.
- Water & Waste Management > Water Management (1.00)
- Energy > Oil & Gas > Upstream (0.47)
- Energy > Power Industry > Utilities (0.46)
After being idle for a period of several years after its first commissioning in 1999, the European OWC pilot plant on the island of Pico in the Azores has been reactivated by 2005 and initial tests have been performed since then. The refurbishment, co-ordinated by the Wave Energy Centre in Portugal, started in 2004, and was supported by National funding under a new Portuguese funding scheme for scientific pilot projects (PRIME/DEMTEC). The activities included the complete replacement of the degraded electrical equipment and refurbishments of the existing mechanical components. This paper describes the Pico plant monitoring during the full-scale demonstration from September 2005 to October 2006 and discusses the data and results obtained so far. INTRODUCTION History and Site The Oscillating Water Column (OWC) European Pilot Plant on Pico Island (Azores) has been practically non-operational since its commissioning in 1999, mainly due to salt- and sweet water infiltrations and subsequent degradation of equipment and problems in some of the mechanical components delivered by the suppliers. The original project was co-funded by EC, the Portuguese government, EDA (Azores utility) and EDP (mainland utility) and involved several Portuguese companies under scientific coordination of Instituto Superior Tรฉcnico (see Falcรฃo, 2000). With the creation of the Wave Energy Centre (WEC) in 2003, the conditions for presentation of a proposal to a national funding scheme (PRIME/DEMTEC) were established, having in view the recovery and test of the plant. The Portuguese institutions EDP, EDA, EFACEC, Consulmar, Irmรฃos Cavaco, IST and INETI, participated and co-funded the project under co-ordination of WEC. During Sept - Nov 2005 and Jun - Oct 2006 tests have been performed, approaching an accumulated production of 1 MWh delivered to the local grid. Preliminary analysis of results indicates that the equipment works as expected and that energy is produced even with less energetic sea conditions.
- Energy > Power Industry (0.93)
- Energy > Renewable > Ocean Energy (0.89)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Facilities Design, Construction and Operation > Processing Systems and Design > Compressors, engines and turbines (0.68)
- Health, Safety, Environment & Sustainability > Sustainability/Social Responsibility > Sustainable development (0.55)
Time-synchronization System For Cabled Observation Systems
Yokobiki, Takashi (Japan Agency for Marine-Earth Science and Technology) | Eiichiro, Eiichiro (Japan Agency for Marine-Earth Science and Technology) | Araki, Araki (Japan Agency for Marine-Earth Science and Technology) | Tada-nori, Tada-nori (Japan Agency for Marine-Earth Science and Technology) | Goto, Goto (Japan Agency for Marine-Earth Science and Technology) | Kenichi, Kenichi (Japan Agency for Marine-Earth Science and Technology) | Asakawa, Asakawa (Japan Agency for Marine-Earth Science and Technology)
A new time-synchronization system for cabled underwater observation systems was developed and evaluated. It provides accurate GPS time signal (1PPS Signal) and accurate clock to underwater sensors. 1PPS signal is essential for longterm and continuous acoustical geodetic monitoring with cabled observation system. Geodetic observation on the seafloor is important in Japan for disaster mitigation, as most plate boundaries which cause mega-thrust earthquakes are placed under seafloor. The system will be installed in the Tokai-SCANNER which will be constructed off Toyohashi in central Japan. The evaluation tests show it can provide 1PPS signal of about 10 nanoseconds accuracy which surpasses the required accuracy for acoustical geodetic monitoring. This paper will describe the outline of the system and the results of evaluation test. INTRODUCTION As cabled observation systems enable long-term continuous four-dimensional monitoring as they provide electric power and communication line to sensors deployed on seafloor. It can be used in many disciplinary such as seismology, oceanology, marine biology, etc. One of its promising applications is a long-term acoustical geodetic monitoring. By monitoring the movement of acoustic transmission delay between acoustic transmitter and receiver deployed on seafloor for example, we can continuously monitor the deformation of seafloor over long time. If the system is connected with transducers and associated electronics for GPS/Acoustic combined systems, it also enables long-term and continuous geodetic monitoring. As most of plate boundaries around Japan, which periodically cause catastrophic earthquakes, are located beneath seafloor, long-term acoustic geodetic monitoring on seafloor close to plate boundaries is essential to understand the movement of plate boundaries for disaster mitigation. For the acoustical geodetic monitoring, an accurate time-synchronization signal is needed. As the acoustic transmission velocity is about 1,500 meters/s, a time-synchronization signal of one microsecond accuracy is needed to ensure acoustical geodetic monitoring of about one millimeter accuracy.
Next generation nuclear power systems, high-power particle accelerators and space technology will inevitably rely on higher performance materials that will be able to function in the extreme environments of high irradiation, high temperatures, corrosion and stress. The ability of any material to maintain its functionality under exposure to harsh conditions is directly linked to the material structure at the nano- and micro-scales. Understanding of the underlying processes is key to the success of such undertakings. This paper presents experimental results of the effects of radiation exposure on several unique alloys, composites and crystals through induced changes in the physio-mechanical macroscopic properties. INTRODUCTION Material performance under the combined influence of intense radiation fluxes, elevated temperatures, corrosive environment and applied stress represents the limiting factor for several next generation systems that include and are not limited to nuclear reactors, fusion technology, multi-MW class particle accelerators and to a lesser extent space-related applications. Exposure of materials to any combination of these harsh conditions will result in at times dramatic changes in their macroscopic physical properties, which in turn ensure their functionality. Macroscopic physical properties are the expression of processes taking place either at the atomic level of the material lattice as well as at the nano- and micro-scale. The dominant role of radiation-induced changes in properties of materials has long been recognized but despite the wealth of experimental as well as reactor-based experience data gaps in the understanding of the mechanisms responsible still remains. It is generally accepted, however, that the buildup of displacement damage (lattice disorder due to elastic collisions of bombarding particles and solid material atoms) with radiation exposure causes gradual but permanent changes in component performance and limits device lifetime in a radiation environment. While the database and experience on material irradiation damage is quite extensive as a result of nuclear reactor operation, it almost exclusively applies to the effects of neutron bombardment on materials.
- Materials (1.00)
- Energy > Power Industry > Utilities > Nuclear (0.88)
- Health & Medicine > Nuclear Medicine (0.87)
A new small diameter cone sampler has been developed and its applicability for Pleistocene Osaka Ma12 clay, Ibaraki organic and clay deposits was examined (Shogaki and Sakamoto, 2004; Shogaki, et al. 2004). In this paper, a cone information transmission system by wireless is outlined. The relationship between cone information and undrained shear strength of samples obtained from a cone sampler is examined and the applicability of the cone sampler for natural clay deposits is examined through unconfined compression (UCT) and index properties tests for samples obtained this way. The cone information transmission was not affected by rod length at a range of 34 m. There was no difference in cone information between a cone sampler having a wireless transmission system and one using a standard wire transmission. Concerning the cone sampler, the sampling cost is lower and soil sampling time is shorter, since an undisturbed soil sample can be taken without a borehole. The cone sampler can take higher quality samples and cone information. INTRODUCTION A new small diameter cone sampler has been developed and its applicability for Pleistocene Osaka Ma12 clay, Ibaraki organic and clay deposits was examined (Shogaki and Sakamoto, 2004; Shogaki, et al. 2004). The cone sampler can take high quality samples having low sample disturbance since the penetration speed and force of the cone sampler is higher than those of the 75-mm, 75D and 84T samplers identified in JGS 1221-1995, JGS 1222-1995 and JGS 1223-1995. The cone sampler can conduct cone penetration tests without a borehole. However, cone information, such as penetration resistance (qt), pore water pressure (u), sleeve friction (fs) and inclination (ic) under cone penetration cannot be measured using a standard wire transmission from the cone sampler. OUTLINE AND CHARACTERISTICS OF THE WIRELESS CONE INFORMATION TRANSMISSION SYSTEM The longitudinal section of the cone sampler is shown in Fig. 1.
We numerically analyze the flushing effects and the likelihood of a vertical breakwater consist of immersed water channel and water chamber, originally proposed by Nakamura (1999, 2003, 2005) for the alleviation of reflected waves, as a wave energy extraction measure. As a wave driver, we use the Nervier-Stokes equations and mass balance equation, and the numerical integration of which is carried out based on the smooth particle hydrodynamics with a Gaussian Kernel function. As a water level in front of curtain wall, where an anti-node of standing wave due to partial reflection is located, approaches its lowest level, a unidirectional flow in the water chamber formed by a preceding wave starts to move offshore. Once it exits water chamber, this energetic flow feeds necessary energy into the vortex in front of the water chamber to sustain long enough until next wave comes. Considering the facts that an intensity of the flow absorbed through the immersed water channel is strongly proportional with an extent and strength of the vortex formed on offshore side of front curtain wall and a curved path line of sucked water particles, we can deduce that aforementioned vortex is responsible for the flushing effects of the vertical breakwater consist of immersed water channel and water chamber. It is also shown that net flux through the immersed water channel increases as the mass inflow into a water chamber is getting larger (T=1.4sec, Le =6cm), which also confirm our conclusion. INTRODUCTION Due to the sharp increase in crude oil price and exhaustion of fossil energy such that we have been merely 41 years, 67 years, 192 years away from running out of oil, natural gas, and coal, respectively, the development of alternative, renewable energy is emerged as an urgent task in South Korea, which heavily relies on the imported oil from overseas.