A demonstrative study for the wind and solar hybrid power system

In March 1995, a small scale wind and solar hybrid power system was installed at Ashikaga Institute of Technology. Until now, the authors have acquired the data of the output of the hybrid power plant along with wind speed, wind direction, and the solar radiation, in order to demonstrate a complementary relationship between solar energy and wind energy.After nine months operation of the system, the authors confirmed that there exists a complementary relationship between solar energy and wind energy. We also found, however, that the power output by wind does not have much prospect compared to that by solar cell especially in summer season in Ashikaga area.     

Value of Bulk Energy Storage for Managing Wind Power Fluctuations

This paper considers the impact of uncertain wind forecasts on the value of stored energy (such as pumped hydro) in a future U.K. system, where wind supplies over 20% of the energy. Providing more of the increased requirement for reserves from standing reserve sources could increase system operation efficiency, enhance wind power absorption, achieve fuel cost savings, and reduce CO₂ emissions. Generally, storage-based standing reserve's value is driven by the amount of installed wind and by generation system flexibility. Benefits are more significant in systems with low generation flexibility and with large installed wind capacity. Storage is uniquely able to stock up generated excesses during high-wind/low-demand periods, and subsequently discharge this energy as needed. When storage is combined with standing reserve provided from conventional generation (e.g., open-cycle gas turbines), it is valuable in servicing the highly frequent smaller imbalances     

Generation of typical operation curves for hydrogen storage applied to the wind power fluctuation smoothing mode

In this paper, a typical-operation-curve generation method of a hydrogen energy storage system operating under the mode of stabilizing wind power fluctuations is proposed. This method is used to optimize the power and capacity configuration of the energy storage system. The time series curves of the charging and discharging powers of the hydrogen energy storage are obtained by EMD decomposition, and the curves are classified according to the similarities and differences of the characteristic par...     

风力资源利用与新能源产业发展——基于玉门市产业转型和新能源基地建设考察

由于能源供应紧张和气候变化等因素影响,风力资源利用正受到全球性的广泛关注和热情实践。2009年全球风电装机容量新增3750×104kW,总装机容量达到1.58×108kW,同比增长31%;预计2020年全球风电装机将达到12.31×108kW,年装机达到1.5×108kW,风力发电量将占全球发电总量的12%。至2009年,中国风电装机容量累计达2600×104kW,预计到2020年风电占全国电力总装机容量的比例将达到10%左右。发展以风电、光电等可再生能源为主的新能源产业,是应对金融危机的有效途径,同时也是能源结构调整的必然选择。玉门市可供开发利用的风能资源储量在2000×104kW以上,全国首座千万千瓦级风电基地一期工程已在玉门开工奠基,为建设风、光、火、核互补的新能源基地创造了有利条件,但同时调峰电源、输出电网、电量消纳等问题也制约着其风电产业的健康快速发展。从全国情况看,存在风电产业成长与电网建设不协调、风电技术研发和设备制造能力不强、配套政策不完善等问题。建议国家应强化政策支持,把风电及其配套产业纳入国民经济发展规划统筹考虑,加大对技术研发的支持力度。     

风光互补电动汽车储能电站系统优化设计

通过对唐山市区太阳能和风能资源状况调查分析,对全年不同方位角和倾角上的太阳能辐射量进行模拟计算,得出南偏东9.8°方向、倾角为39.7°的倾斜面上接收的太阳能辐射量最大,其值为1.62×106Wh/m2。研究中对3kW风力发电机和1kW光伏发电系统的发电量进行了计算,并以1辆纯电动轿车为负载进行了容量配比优化,设计了风力发电系统、风光互补系统及光伏系统三种不同的方案,经过对各方案的经济性、可靠性及稳定性分析,得出最佳的设计方案为风光互补发电系统,该系统风力发电装机容量为3kW,光伏发电装机容量为8.96kW。     

陕西省金润河北镇风电场风能资源开发评估

对陕西省宝鸡市陇县金润河北镇风电场气象条件、风功率密度、平均风速、主导风向等风能参数进行分析评价。结果表明,测风塔100 m高度月平均风速、月平均风功率密度最大均出现在4月,最小均出现在8月;测风塔100 m高度主导风向为SSW(南西南),主要风能方向为SSW(南西南),风电场风功率密度等级为1级。风电场安装20台2500 kW的风电机组,装机容量50 MW,年设计发电量1.33485×108 kW·h,年出厂电量9.5426×107 kW·h。结果可为其他风电场选址和发电量估算提供参考。     

Research on non-grid-connected wind power/water-electrolytic hydrogen production system

Hydrogen has been recognized as the most promising future energy carrier. At present, industrial hydrogen production processes are not independent of traditional energy resources, which could easily cause secondary pollution. China has abundant wind energy resources. The total installed capacity of wind power doubled every year in the last five years, and reached 26 000 MW by the end of 2009, but over 9880 MW wind turbines were not integrated into grid because of the peak shaving restraint. In this paper, wind power is directly used in water-electrolytic process by some technical improvements, to design non-grid-connected wind power/water-electrolytic hydrogen production system. The system all works properly, based on not only the wind/grid complementary power supply but also the independent supply of simulation wind power. The large-scale fluctuation of current density has little impact on current efficiency and gas quality, and only affects gas output. The new system can break through the bottlenecks of wind power utilization, and explore a diversified development way of large-scale wind power, which will contribute to the development of green economy and low carbon economy in China.     

基于调峰能力分析的电网弃风评估方法及风电弃风影响因素研究

  [目的]  由于风电出力的间歇性、随机性和反调峰特性,大规模可再生能源风电并网造成京津唐地区冬季供热季弃风现象愈加严重。  [方法]  为了能够定量研究电源调峰、联络线外送等弃风因素变化时对电网弃风的影响情况,从而准确衡量不同情形下电网对风电的接纳能力,文章从系统调峰的角度,以电热负荷平衡约束、机组出力约束为条件建立风电弃风评估模型。  [结果]  对京津唐电网弃风情况的模拟结果表明,常规电源调峰越深、联络线外送深度越小,系统接纳风电出力的空间越大;而过快的风电装机容量增长速度和较高的热电机组供热比率,会抑制风电出力,从而导致弃风。  [结论]  因此,可通过激励系统中常规电源积极主动进行调峰、控制联络线外送峰谷差和热电机组出力范围来提高系统接纳风电的能力;而根据未来规划水平,选取某一比例的风电装机容量增长速度,即可确定最佳的风电并网规模,控制弃风电量在一定水平内。     

Location of Swedish wind power—Random or not? A quantitative analysis of differences in installed wind power capacity across Swedish municipalities

The amount of installed wind power varies significantly across municipalities although the financial support for wind power production and the technology available is identical in all Swedish municipalities. This study analyses how local differences between municipalities, such as local wind prerequisites and socioeconomic conditions, might explain the establishment of wind power. The analysis is carried out for a cross section of Swedish municipalities. The time periods before and after 2006 are analyzed separately; and results reveal that the factors affecting wind power establishments are different between the two periods. In the later time period we found a statistically significant positive relationship between good wind resources and the presence of wind power as well as with the amount of wind energy installed. This result is consistent with the idea that the first wind power investments in Sweden were highly affected by individual wind energy enthusiasts, while in the more recent large-scale investments market-based judgments about future profitability may have become increasingly important. In addition, previous experience seems to be a factor that in itself facilitates additional future wind power establishments, thereby pointing to the role of accumulated institutional capacity.     

Optimal integration of wind farms to isolated wind-Diesel energy system

Wind farms installed on isolated systems are subject to significant restrictions, affecting their expected energy yield and, hence, the feasibility of investments. As wind power penetrations increase in isolated power systems, it is very important to understand how variations in wind plant outputs affect the operation of the isolated system on a day to day basis and what the associated added costs are. In this paper, a wind-Diesel coordination generation scheduling (WCGS) software is developed for appropriate assessment of the added cost to cover the unpredictable wind generator output variations. The developed WCGS software is also a useful tool for the system planner to predict the energy cost and the fuel saving from the expected new wind-Diesel systems. Several technique constraints are applied to determine the optimal proportion of wind generator capacity that can be integrated into the existing system. A simple benefit cost ratio (BCR) is used in this study to evaluate the investment effectiveness of the installation of wind farms for an isolated hybrid system. Numerical experiments are included to understand the wind generator output variations in system operating cost analysis and to assess the impact and economic benefits of the installation of wind farms.     

基于高斯混合聚类的海上风电出力特征曲线提取方法及其在电量平衡计算中的应用

[目的]为了减少化石能源消耗和改善环境污染问题,海上风力发电是解决问题的有效方式之一。然而,海上风电存在间歇性强、波动性大、双向调峰性等问题,研究其出力特性曲线对海上风电消纳具有重要意义。[方法]提出一种基于贝叶斯信息准则的高斯混合聚类模型,对海上风电原始出力曲线进行分类和特征曲线提取。[结果]得到能够反映不同海风区域特点的海上风力特性曲线,并应用于海上风电出力的电量平衡计算。[结论]最后,以沿海某省份海上风电15 GW装机规模下不同海风区域原始海上风电出力曲线为研究对象,验证所提方法的有效性。     

Prospects of wind farm development in Saudi Arabia

This paper presents the energy output of wind farms in terms of unadjusted energy, gross energy, renewable energy delivered, specific yield and wind farm capacity factor. The analysis also includes the comparison of energy output from two methods: (i) the RETScreen model and (ii) the actual frequency and wind turbine power curve. The energy output analysis is done using three wind energy conversion systems of rated capacity 600, 1000, and 1500 kW. The study is performed for 30 MW installed capacity wind farms at five coastal locations in Saudi Arabia.Furthermore, the RETScreen software is also used to perform the economical feasibility study of the wind farms at these locations. The study concludes that of the five wind parks, Yanbo and Dhahran are the only two sites where wind park development is economically feasible. Finally, wind park development at Yanbo will result in a reduction in greenhouse gases of 31369, 23601, and 26087 tons each year, corresponding to 1500, 1000, and 600 kW machine wind parks, respectively. On the other hand, at Dhahran, installation of wind machines of 1500, 1000, and 600 kW sizes will reduce the GHGs by 26183, 19247, and 21533 tons per year.     

Pumped storage in systems with very high wind penetration

This paper examines the operation of the Irish power system with very high levels of wind energy, with and without pumped storage. A unit commitment model which accounts for the uncertainty in wind power is used. It is shown that as wind penetration increases, the optimal operation of storage depends on wind output as well as load. The main benefit from storage is shown to be a decrease in wind curtailment. The economics of the system are examined to find the level at which storage justifies its capital costs and inefficiencies. It is shown that the uncertainty of wind makes the option of storage more attractive. The size of the energy store has an impact on results. At lower levels of installed wind (up to approximately 50% of energy from wind in Ireland), the reduction in curtailment is insufficient to justify building storage. At greater levels of wind, storage reduces curtailment sufficiently to justify the additional capital costs. It can be seen that if storage replaces OCGTs in the plant mix instead of CCGTs, then the level at which it justifies itself is lower. Storage increases the level of carbon emissions at wind penetration below 60%.     

Framework design of a hybrid energy system by combining wind farm with small gas turbine power plants

Owing to the stochastic characteristic of natural wind speed, the output fluctuation of wind farm has a negative impact on power grid when a large-scale wind farm is connected to a power grid. It is very difficult to overcome this impact only by wind farm itself. A novel power system called wind-gas turbine hybrid energy system was discussed, and the framework design of this hybrid energy system was presented in detail in this paper. The hybrid energy system combines wind farm with several small gas turbine power plants to form an integrated power station to provide a relatively firm output power. The small gas turbine power plant has such special advantages as fast start-up, shutdown, and quick load regulation to fit the requirement of the hybrid energy system. Therefore, the hybrid energy system uses the output from the small gas turbine power plants to compensate for the output fluctuation from the wind farm for the firm output from the whole power system. To put this hybrid energy system into practice, the framework must be designed first. The capacity of the wind farm is chosen according to the capacity and units of small gas turbine power plants, load requirement from power grid, and local wind energy resource distribution. Finally, a framework design case of hybrid energy system was suggested according to typical wind energy resource in Xinjiang Autonomous Region in China.     

Current facts about offshore wind farms

This paper reviews offshore wind projects with a wide perspective. The current situation of the offshore wind market is presented, pointing out the countries leading the process in terms of installed capacity and in terms of technological leadership. Feasibility studies of alternative offshore wind farms (OWFs) are interesting not only in relation to the business but in relation to the techno-economical analyses that engineering researchers need to do. Details about the average energy yield assessment, the costs and the price for the purchased energy are commented on, as key elements of those feasibility studies. The higher cost of renewable energy sources of electricity (RESE) when compared with conventional sources, demands appropriate policy support. The European regulatory framework and the support schemes established by European Member States are presented, as well as the role that different transmission system operators (TSOs) are playing at the moment. Finally, most of the OWFs currently operating are presented, analysing the technical characteristics of their electric subsystems: the wind energy conversion systems (WECSs) transforming the kinetic energy of the wind into electricity, the collector system (CS) gathering the power output of all the turbines to a central collection point (CCP) and the transmission system (TS) taking that power to the onshore main grid.     

Framework design of a hybrid energy system by combining wind farm with small gas turbine power plants

Owing to the stochastic characteristic of natural wind speed, the output fluctuation of wind farm has a negative impact on power grid when a large-scale wind farm is connected to a power grid. It is very difficult to overcome this impact only by wind farm itself. A novel power system called wind-gas turbine hybrid energy system was discussed, and the framework design of this hybrid energy system was presented in detail in this paper. The hybrid energy system combines wind farm with several small gas turbine power plants to form an integrated power station to provide a relatively firm output power. The small gas turbine power plant has such special advantages as fast start-up, shutdown, and quick load regulation to fit the requirement of the hybrid energy system. Therefore, the hybrid energy system uses the output from the small gas turbine power plants to compensate for the output fluctuation from the wind farm for the firm output from the whole power system. To put this hybrid energy system into practice, the framework must be designed first. The capacity of the wind farm is chosen according to the capacity and units of small gas turbine power plants, load requirement from power grid, and local wind energy resource distribution. Finally, a framework design case of hybrid energy system was suggested according to typical wind energy resource in Xinjiang Autonomous Region in China.     

Current situation of the wind energy use and investigation of wind resources in the coastal region of the Baltic Sea in Lithuania

In this paper current situation and future prospects of the use of wind energy and wind power resource assessment experience in Lithuania are reviewed. Installed wind power capacity has increased from 6.4 to 54.84 MW in Lithuania in 2006. During last five years wind power resource assessment was carried out, wind measurements were generalized and on the basis of obtained results Lithuanian wind resources map was developed. Measurements have shown that the most suitable region for building WT of big capacity is the 10 km wide coastal strip in Lithuania. The suitability of several existing WT sites was evaluated by the power output coefficient, which describes the efficiency of installed WT. The aim of this work is to present the current situation of wind energy development and the results of the investigation of wind climate conditions in the coastal region of the Baltic Sea in Lithuania.     

结合防波堤的振荡摇摆式波浪能装置试验研究

讨论一种结合防波堤的振荡摇摆式波浪能装置的结构和工作原理,并在河海大学河口航道综合试验厅进行物理模型试验。试验以重块和不锈钢板间的摩擦力作为波浪能转换装置的负载阻尼,通过测量不锈钢板两端的拉力及其位移计算波浪能转换输出功率。结果表明,当入射波的周期和浮体的固有周期接近时,浮体的运动接近共振状态,此时波浪能转换平均输出功率和转换效率最高,分别可达0.05 W和17.9%。入射波周期较大时,装置的波浪能转换输出功率较高,但此时其波浪能转换效率低于入射波周期较小时。水深对于浮体的姿态和运动特性起到关键作用,结果表明水深为60 cm时波浪能转换输出功率和转换效率最高。     

Wind power potential of Baja California Sur, México

This work is an analysis of wind characteristics of Baja California Sur (BCS), México, during the period from February 1997 to February 1998. Fifteen wind stations located in the eastern coastal area recorded the wind speed and wind direction for this region. The wind resources of BCS were recorded and the annual average wind speed, power density, and annual energy density at 10 m above ground level are presented here.We considered the wind data from El Cardón, BCS, as a case study. This location can be considered to be representative of the 15 wind stations that were installed in BCS. Using the Weibull probability density function, we estimated the wind energy output and the capacity factor for two different wind turbines during the year. The capacity factors for both wind turbines were estimated at close to 25%. Considering the wind energy output and the capacity factor, we estimated the levelized production costs for both wind turbines. Taking into account two different discount rates of 7% and 10%, we developed data for the levelized production cost of both wind turbines.     

Effective policies for renewable energy—the example of China's wind power—lessons for China's photovoltaic power

China, one of the global biggest emitter of CO₂, needs promotion renewable energy to reduce air pollution from its surging fossil fuel use, and to increase its energy supply security. Renewable energy in its infancy needs policy support and market cultivation. Wind power installed capacity has boomed in recent year in China, as a series of effective support policies were adopted. In this paper, I review the main renewable energy policies regarding to China's wind power, including the Wind Power Concession Program, Renewable Energy Law, and a couple of additional laws and regulations. Such policies have effectively reduced the cost of wind power installed capacity, stimulated the localization of wind power manufacture, and driven the company investment in wind power. China is success in wind power installed capacity, however, success in wind-generated electricity has yet achieved, mainly due to the backward grid system and lack of quota system. The paper ends with the recommended best practice of the China's wind power installed capacity might be transferable to China's photovoltaic power generation.