Wave energy potential in the Baltic Sea and the Danish part of the North Sea, with reflections on the Skagerrak

Wave power, along with renewable energy-generating sources like tides and streams, is underestimated considering its advantageous physical properties and predictability. This paper examines possible examples of wave power installations in the Baltic Sea and the Danish part of the North Sea. Hindcasting data is used allowing estimations of wave energy generated and results show promising areas in the North Sea, but also several parts of the Baltic Sea are of interest. The study is based upon linear generator technique, placed on the seabed using point-absorbers arranged in arrays of up to several thousand units. The study aims at showing the physical possibilities of wave energy, including economical feasibility and environmental advantages of wave energy even in moderate wave climates. With discussion from two examples in the Baltic Sea, one in the Danish North Sea and a new pilot study site in the Swedish part of Skagerrak, this study show feasible illustrations of wave energy takeouts. Project examples vary in size due to distance to grid, grid voltage, and may thus be economically feasible. Examples also show considerations in societal and nature conservation matters, including aspects such as industrial and military interests, archaeological or marine reserves and local geology. The authors conclude that wave energy electric conversion is an option that needs more attention and which has several advantages compared to conventional renewable sources. Sound engineering, in combination with producer, consumer and broad societal perspective is advised for a sustainable development of wave energy conversion.     

南海岛礁海域波浪能资源分析及总量评估

基于波浪能的能通量原理,建立代表区段长度的概念,提出针对于海岛海域的波浪能资源蕴藏量评估方法及具体公式。通过第3代波浪谱模型SWAN对南海海域近10年的波浪场进行数值模拟,并利用实测波浪资料进行验证。在此基础上重点刻画该海域波高、周期、能流密度等波浪能资源时空分布特征,利用新方法对南海岛礁海域波浪能资源蕴藏量进行估算。结果表明,以离岸50 km等值线为波浪能量输入线时,南海群岛波浪能理论蕴藏量约为18300 MW。其中,西沙群岛海域约为2600 MW,东沙群岛海域为2120 MW,中沙群岛海域约为6720 MW,南沙群岛海域约为6860 MW。     

南海海域波浪能资源模拟评估

为了大范围评估波浪能资源,文章通过WAVEWATCH-Ⅲ模式结合高精度的CCMP风场资料对南海海域四季的波浪能资源进行定量计算和定性分析,分析结果表明:南海海域的波浪能分布表现出明显的空间和季节分布特性,大值区主要集中在中北部海域、东沙群岛和台湾岛邻近海域,而低值区主要分布在北部湾、曾母暗沙以及泰国湾周边海域;在冬季,南海海域的波浪能流密度及其稳定性方面均比其他季节有明显优势,且冬季的平均波浪能有效储量的总体水平表现为全年最高;南海北部、台湾岛东南部海域以及东沙群岛附近海域的波浪能资源丰富,是资源优势区域,适宜波浪能开发。     

10-year high resolution study of wind,sea waves and wave energy assessment in the Greek offshore areas

Nowadays, renewable energy resources are one of the top priority issues for the environmental and political community. In particular, wind and wave energy are two of the most promising solutions, with great potential from research and technological point of view. In this work, an integrated high resolution platform, consisting of state-of-the-art wind-wave numerical models, has been utilized and produced a 10-year database containing all the relevant environmental parameters for a detailed resource assessment over the Greek seas. The results of the atmospheric and sea wave numerical models concerning the environmental parameters that directly affect the wave energy potential were evaluated. High resolution maps for the coastal and offshore areas of Greece present sea wave and wind climatological characteristics, as well as the relevant distribution of the wave energy potential. A number of statistical indices have been employed for analyzing the output of the models, including the potential impact of extreme values and the corresponding distribution of the above parameters, which optimally describe the spatial and temporal analysis of the wave power potential over the area of interest. It is shown that the regions with increased wave energy potential are mainly the western and southern seas of Greece, which are usually exposed to swell from central and south Mediterranean Sea.     

Economical considerations of renewable electric energy production—especially development of wave energy

Investments in renewable energy plants normally only take standard economic key figures into account, such as installed rated power, the market price of energy and the interest rate. The authors propose that the degree of utilisation, i.e. the ratio of yearly produced energy in the installation to the installed power, must be included due to its significant impact on the present value of the investment. A site with a limited average wave height could be of economic interest if the utility factor for the installation is high, since the investment cost (associated with the power installed) can be better adjusted to conditions at the particular site. In the case of wave power from the Baltic Sea with its limited variation in wave height (and limited average wave height), this indicates that the economic potential is best for smaller units.     

Improving the assessment of wave energy resources by means of coupled wave-ocean numerical modeling

Sea waves energy represents a renewable and sustainable energy resource, that nevertheless needs to be further investigated to make it more cost-effective and economically appealing. A key step in the process of Wave Energy Converters (WEC) deployment is the energy resource assessment at a sea site either measured or obtained through numerical model analysis. In these kind of studies, some approximations are often introduced, especially in the early stages of the process, viz. waves are assumed propagating in deep waters without underneath ocean currents. These aspects are discussed and evaluated in the Adriatic Sea and its northern part (Gulf of Venice) using locally observed and modeled wave data. In particular, to account for a “state of the art” treatment of the Wave–Current Interaction (WCI) we have implemented the Simulating WAves Nearshore (SWAN) model and the Regional Ocean Modeling System (ROMS), fully coupled within the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) system. COAWST has been applied to a computational grid covering the whole Adriatic Sea and off-line nested to a high-resolution grid in the Gulf of Venice. A 15-year long wave data set collected at the oceanographic tower “Acqua Alta”, located approximately 15 km off the Venice coast, has also been analyzed with the dual purpose of providing a reference to the model estimates and to locally assess the wave energy resource. By using COAWST, we have quantified for the first time to our best knowledge the importance of the WCI effect on wave power estimation. This can vary up to 30% neglecting the current effect. Results also suggest the Gulf of Venice as a suitable testing site for WECs, since it is characterized by periods of calm (optimal for safe installation and maintenance) alternating with severe storms, whose wave energy potentials are comparable to those ordinarily encountered in the energy production sites.     

An overview of ocean renewable energy resources in Korea

Korea relies on imported fossil fuels to meet its energy consumption demands. As such, there is a need to investigate alternative energy resources such as renewable energy. In this paper, assessments of the potential of various ocean renewable energy resources in the sea around Korea; potential sources of energy including wave energy, tidal energy, tidal current energy and ocean thermal energy. Tidal energy and tidal current energy are likely to play an important role in meeting the future energy needs of Korea, whereas the potentials of wave energy and ocean thermal energy for the same are relatively low. The level of technical development and the renewable energy market in Korea is currently in an early stage. The government will have to be more aggressive in the promotion of renewable energy to achieve sustainable development in Korea.     

22-Year wave energy hindcast for the China East Adjacent Seas

In order to investigate the wave energy resource, the third-generation wave model SWAN is utilised to simulate wave parameters of the China East Adjacent Seas (CEAS) including Bohai, Yellow and East China Sea for the 22 years period ranging from 1990.1 to 2011.12. The wind parameters used to simulate waves are obtained by the Weather Research & Forecasting Model (WRF). The results are validated by observed wave heights of 7 stations. The spatial distributions of wave energy density in the CEAS are analysed under the 22-year largest envelop, mean annual and season averaged wave conditions. Along China east coastal, the largest nearshore wave energy flux occurs along the nearshore zones between Zhoushan Island and south bound of CEAS area. The wave energy resources at Liaodong Peninsula Headland and East Zhoushan Island where economy develops rapidly are also studied in detail. For the two sites, the monthly averaged wave energy features of every year for the 22 years are investigated. The wave energy resources of the two potential sites are characterised in terms of wave state parameters. The largest monthly averaged density for the two sites occurs at Zhoushan Island adjacent sea and amounts to 29 kW/m.     

Assessments of wave energy in the Bohai Sea,China

Wave fields in the Bohai Sea are continuously simulated by the third-generation wave model SWAN in order to determine the wave energy resources from 1985 to 2010. The wind parameters used to simulate waves are obtained by the Regional Atmospheric Modeling System (RAMS). Comparisons of significant wave heights between simulations and observations show good agreement. The spatial distributions of mean monthly and annual averaged significant wave height and wave power flux are presented. Wave energy roses and temporal variations of average wave power density at five typical points in the Bohai Sea are calculated. Furthermore, the correlations between significant wave height and wave energy period are studied in scatter and energy diagrams.     

Monitoring of energy supply sustainability in the Baltic Sea region

BASREC (Baltic Sea Region Energy Cooperation) was established in 1999. It brings together the 11 countries around the Baltic Sea (Denmark, Estonia, Finland, Germany, Iceland, Latvia, Lithuania, Norway, Poland, Russia, and Sweden) and the European Commission. BASREC offers a unique regional forum, in which policies and projects of regional and broader significance can be prepared and implemented. Five working groups within BASREC, for Bioenergy, Climate Change, Electricity, Energy Efficiency and Gas, were active in the period 2003–2005. These working groups quite well represent the priorities of regional energy cooperation in the Baltic Sea region. Since the EU participates actively in BASREC activities, this kind of cooperation can provide for the EU sustainable energy policy promotion in non-member countries, such as Russia, and can help sharing the experience between old and new member states as well as facilitate the know how transfer from such highly developed and advanced in sustainable development countries as Iceland and Norway to less developed ones.     

Assessment of wave energy potential and its harvesting approach along the Indian coast

The present scenario of energy market is highly volatile due to large oscillation in the fossil fuel prices. During these periods, the high energy demand for the industries is being partially met through non-conventional energy sources such as wind and solar power. The large untapped energy potential in the Ocean is yet to be exploited due to many technological constraints. The recent decades have shown positive developments worldwide towards the ocean wave energy converters. In the present study, an improved wave energy potential estimate has been made. Based on various parameters such as physical site characteristics, environmental conditions and socio-economic regional state, the selection criteria have been suggested. This would form the basis for energy device selection for the decision makers.     

Research of the wind energy resource distribution in the Baltic region

Governmental support and the availability of large unpopulated areas on the coasts of the Baltic countries make attractive the use of these lands for siting large wind power plants (WPP).Studies in the area of wind energy resource distribution are carried out by the IPE with collaboration with the VeU. The observations of wind speed were made using the measuring complex NRG LOGGER 9200 Symphonie.The results of long-term observations on the wind energy density fluctuations at heights of 10–60 m in the area on the Baltic Sea coast of Latvia are presented in the form of tables, bar charts and graphs.The wind speed distribution is analysed. The coefficients of approximating functions for two areas of different terrain types have been calculated, and extrapolation results for the distribution curves of wind speed and energy density obtained.The acoustic noise level distribution around a planned WPP has been modelled.     

美国波浪能发电场建设对中国波浪能的启示

美国海域波浪资源丰富,在波浪能开发及利用方面开展了许多卓有成效的工作,值得借鉴和参考.通过分析美国地理环境特点、气候环境特点、波浪能资源分布特点,获得了美国波浪能资源概况;通过分析美国能源使用情况、波浪能资源开发现状及规划,掌握了美国波浪能的开发政策及方向;通过归纳波浪能发电场建设的关键因素、现状,阐述了建设波浪能发电...     

An investigation of wind characteristics on the campus of Izmir Institute of Technology, Turkey

The European Wind Atlas shows a very high wind energy capacity over the Aegean Sea and its coastal regions. Therefore, the western region of Turkey, which has a long coast along the Aegean Sea, appears to have high potential of wind energy. As a result of this fact, several studies have been performed to estimate the wind potential, especially, in western Turkey. However, due to the absence of a reliable and accurate Wind Atlas of Turkey, further studies on the assessment of wind energy in Turkey are necessary. In this study, the characteristics of wind on the campus of Izmir Institute of Technology, located in Cesme peninsula which has long coastline along the Aegean Sea, were studied over a period of one year. Measured data set and its evaluation showed that Izmir Institute of Technology campus area has a considerable wind energy potential. The study presented here is an attempt to promote wind energy in Turkey and to bridge the gap in order to create prospective Turkish Wind Atlas.     

计及恶劣天气约束的海上风能波浪能资源分布研究

基于ERA5和全球海洋波浪再分析资料,统计分析2005—2019年间110°E~130°E、15°N~35°N海域的恶劣天气事件时空分布特征,在剔除恶劣天气时段下,对风能密度、波浪能密度、风能变异系数和波浪能变异系数进行分析。结果表明：2005—2019年间恶劣天气事件整体呈递增趋势,季节性差异大;总体上深远海海域恶劣天气出现时段比近海多,南海北部恶劣天气事件出现时段最多;在剔除恶劣天气时段后,东海深远海存在风能丰富且波浪能较密集的海域,台湾海峡以南近海风能丰富且稳定,但波浪能不密集且不稳定,南海北部近海海域波浪能比深远海更密集且更稳定,这与不剔除恶劣天气时段情况下波浪能分布特征存在较大差异。     

Building design: Realising the benefits of renewable energy technologies

The focus of the world's attention on environmental issues in recent years has stimulated responses in many countries which have led to a closer examination of energy conservation strategies for conventional fossil fuels. Buildings are important consumers of energy and thus important contributors to emissions of greenhouse gases into the global atmosphere. The development and adoption of suitable renewable energy technologies has an important role; a review of options indicates benefits and some problems. There are two key-elements to the fulfilling of renewable energy technology potential within the field of building design; firstly the instilling of appropriate skills and attitudes in building design professionals, and secondly the provision of the opportunity for such people to demonstrate their skills. This second element may only be created when the population at large, and clients commissioning building design in particular, become more aware of what can be achieved and what resources are required.     

Investigation of the potential of wind–waves as a renewable energy resource: by the example of Cesme—Turkey

There are opinions claiming that 70% of the world energy consumption could be provided from renewable resources by the year 2050. These resources are needed, because fossil fuels both cause pollution of the environment and will be depleted in the near future. In this regard, the objective of this study was to determine the wave energy potential and the costs associated with its application to Turkish waters. To this goal, the wave energy potential in Cesme–Izmir was investigated. Cesme is known to have abundant wind, which plays the primary role in the formation of sea waves. For this purpose, the Solar Energy Institute of Ege University carried out wind velocity measurements within the period from 05.11.1998 to 05.11.1999 at an altitude of 10 m in Cesme. The measured values were regarded as if they were taken at an altitude of 19.5 m from seawater level. With this approach, the Pierson–Moskowitz wave energy spectrum was constructed. Through this wave energy spectrum, wave energy that is to be obtained at the measurement area within one year was determined. The variation of wave energy according to each month was evaluated. Hence, the unit cost of electricity to be produced by a turbine (with a width of 1 m), assumed to be installed at the area of measurements, was calculated.     

Optimal energy production from wind and hydroelectric power plants

All countries attach great importance to renewable energy investments with concern that future fossil-fueled energy resources could be exhausted. Thus, a very large renewable energy production potential may be predicted in not a very distant future. This study is about optimal energy production from wind and hydroelectric power plants at a small scale settlement center. A water resources system with multiple reservoirs in which wind power plants are located around the basin is described in this study. The system has three scenarios, in which wind and hydroelectric power plants are integrated, separated and no wind turbines. In the integrated scenario, by the energy generated in the wind power plants, the released flows from the reservoirs are sent to the reservoirs as a use again. In models of every scenario, optimal operational models for long-term planning are established on the system. The technique of dynamic programming with successive approximations is used in these models. The models are applied to a water resources system with multiple reservoirs presented successively on the main line of the Ceyhan River in the Ceyhan Basin. The results obtained here are evaluated in terms of three scenarios developed for energy production. As a result, it has been seen that the systems of the integrated and separated scenario are similar to energy productions and system without wind turbines produces more little energy production to other scenarios.     

Sustainable energy in Baltic States

Integration of New Member States to the European Union has created a new situation in the frame of implementation of the Lisbon strategy and EU Sustainable Development. The closure of Ignalina NPP is the biggest challenge to the energy sector development of the Baltic States. The Baltic States have quite limited own energy resources and in the Accession agreement with the EU Lithuania, Latvia and Estonia have verified their targets to increase the share of electricity produced from renewable energy sources (RES-E) by the year 2010. A wider use of renewable energy and increase of energy efficiency can make a valuable contribution to meeting the targets of sustainable development. The article presents a detailed overview of the present policies and measures implemented in the Baltic States, aiming to support the use of RES and the increase of energy efficiency. The review of possibilities to use the EU Structural Funds (SF) for the implementation of sustainable energy projects in the Baltic States was performed.The use of regional social–economic–environmental indicators is the main key to integrate sustainable energy development at the program deployment level. The indicators to be used should describe the contribution of energy programs to the sustainable development, medium- and long-term trends and inter-relationship between them and the typical energy indicators (saved toe, improved energy efficiency, percentage of RES). Municipalities may play a considerable role by promoting sustainable energy since local authorities are fulfilling their functions in the energy sector via a number of roles. The Netherlands’ example shows that municipalities may act as facilitators by implementing national environmental policy and increasing energy efficiency in an integral part of these activities. The guidelines for Lithuanian local sustainable energy development using the SF co-financing have been presented.     

The use of natural gas and geothermal energy in school units. Greece: A case study

The ever-increasing degradation of the environment along with high demands for energy consumption in buildings has prompted many countries to use other energy sources such as natural gas and geothermal energy instead of oil.This study refers to the use of natural gas in school units in Greece. More specifically, it focuses on school units that are connected to the natural gas network and on the economic and environmental benefits arising from this.In this context, the advantages and disadvantages in using natural gas are compared with those resulting from the use of geothermal energy. In areas which have a significant geothermal potential, the choice of geothermal heating and cooling of large school units is the best solution, but this however does not apply to all areas. Clearly, the development of geothermal energy in school units is still in pilot stage.However, the use of natural gas in school units has been rising over the last decade and it has already contributed to some extent towards the reduction of carbon dioxide and towards saving natural resources. Thus, the survey shows clear advantages in using natural gas and in plans to extend its use to other school units.