Wind park reliable energy production based on a hydrogen compensation system. Part I: Technical viability

Power production from renewable energy resources is increasing day by day. In the case of Spain, in 2009, it represents the 26.9% of installed power and 20.1% of energy production. Wind energy has the most important contribution of this production. Wind generators are greatly affected by the restrictive operating rules of electricity markets because, as wind is naturally variable, wind generators may have serious difficulties on submitting accurate generation schedules on a day ahead basis, and on complying with scheduled obligations. Weather forecast systems have errors in their predictions depending on wind speed. Thus, if wind energy becomes an important actor in the energy production system, these fluctuations could compromise grid stability. In this study technical and economical viability of a large scale compensation system based on hydrogen is investigated, combining wind energy production with a biomass gasification system. Combination of two systems has synergies that improve final results. In the economical study, it is considered that all hydrogen production that is not used to compensate wind energy could be sold to supply the transportation sector.     

Resource potential for wind-hydrogen power in Ukraine

The paper provides an assessment of the current wind energy potential in Ukraine, and discusses developmental prospects for wind-hydrogen power generation in the country. Hydrogen utilization is a highly promising option for Ukraine's energy system, environment, and business. In Ukraine, an optimal way towards clean zero-carbon energy production is through the development of the wind-hydrogen sector. In order to make it possible, the energy potential of industrial hydrogen production and use has to be studied thoroughly.Ukraine possesses huge resources for wind energy supply. At the beginning of 2020, the total installed capacity of Ukrainian wind farms was 1.17 GW. Wind power generation in Ukraine has significant advantages in comparison to the use of traditional sources such as thermal and nuclear energy.In this work, an assessment of the wind resource potential in Ukraine is made via the geographical approach suggested by the authors, and according to the «Methodical guidelines for the assessment of average annual power generation by a wind turbine based on the long-term wind speed observation data». The paper analyses the long-term dynamics of average annual wind speed at 40 Ukrainian weather stations that provide valid data. The parameter for the vertical wind profile model is calculated based on the data reanalysis for 10 m and 50 m altitudes. The capacity factor (CF) for modern wind turbine generators is determined. The CF spatial distribution for an average 3 MW wind turbine and the power generation potential for the wind power plants across the territory of Ukraine are mapped.Based on the wind energy potential assessment, the equivalent possible production of water electrolysis-derived green hydrogen is estimated. The potential average annual production of green hydrogen across the territory of Ukraine is mapped.It is concluded that Ukraine can potentially establish wind power plants with a total capacity of 688 GW on its territory. The average annual electricity production of this system is supposed to reach up to 2174 bln kWh. Thus, it can provide an average annual production of 483 billion Nm³ (43 million tons) of green hydrogen by electrolysis. The social efficiency of investments in wind-hydrogen electricity is presented.     

Optimal operation of microgrid using hybrid differential evolution and harmony search algorithm

This paper proposes the generation scheduling approach for a microgrid comprised of conventional generators, wind energy generators, solar photovoltaic (PV) systems, battery storage, and electric vehicles. The electrical vehicles (EVs) play two different roles: as load demands during charging, and as storage units to supply energy to remaining load demands in the MG when they are plugged into the microgrid (MG). Wind and solar PV powers are intermittent in nature; hence by including the battery storage and EVs, the MG becomes more stable. Here, the total cost objective is minimized considering the cost of conventional generators, wind generators, solar PV systems and EVs. The proposed optimal scheduling problem is solved using the hybrid differential evolution and harmony search (hybrid DE-HS) algorithm including the wind energy generators and solar PV system along with the battery storage and EVs. Moreover, it requires the least investment.     

Exploitation and utilization of the wind power and its perspective in China

Wind energy, as a reliable, natural and renewable electrical power supply, produces no emissions and so it is an excellent alternative to conventional, more heavily polluting fuels in the long term based on the worldwide concern about the environment and energy supply. Wind energy resources in China are affluent, but its distribution are uneven, centralized, and far from both the utility and the high electricity demand markets. This made China's onshore wind power development have such characteristics as large scale, high centralization and far transmission, which is different with that in Europe, where the characteristics are even distribution, decentralized. In past two decades, considering the economic, technical and environmental benefits of wind power, China has given priority to its development. Besides the dramatic growth of large scale grid-connected wind power, household-scale wind power has been used most successfully in remote rural regions in China. Therefore, the development of wind power will be of great importance to alleviate the energy crisis and environmental pollution resulting from the rapid economic growth of China in the future. In this paper, the current development of wind energy utilization in China is investigated, and some critical barriers are discussed. Finally, the perspective of wind energy utilization is presented, where focuses are placed on seven wind power bases.     

Investigation of wind energy potentials in Brunei Darussalam

Conventional power generation mainly depends on natural gas and diesel oil in Brunei Darussalam. The power utility company is now thinking of power generation using natural wind. In this paper, wind energy, being one of the most readily available renewable energy sources, was studied. The wind characteristic, velocity and directions were studied using Weibull distribution based on the measurement of wind speed at two different locations in Brunei Darussalam. These wind speed distributions were modeled using the Wind Power program. The wind rose graph was obtained for the wind direction to analyze the wind power density onshore and offshore. Based on this analysis, it has been found that the wind speed of 3 to 5 m/s has a probability of occurrence of 40%. Besides, the annual energy production at a wind speed of 5 m/s has been found to be in the range between 1000 and 1500 kWh for both the locations in Brunei Darussalam.     

Power limits of grid-connected modern wind energy systems

Wind energy is a prominent area of application of variable speed generators operating on the constant grid frequency. A modern wind energy system of this type consists of a surface mounted permanent-magnet generator with a frequency converter, which allows variable speed operation. The maximum power capability of the wind energy system is limited by the grid inverter. The theoretical formulation for active and reactive power limits is given. This formulation is used to set power reference limits to the inverter. Two different regions are distinguished depending on the tolerable Ac current harmonic distortion. Experimental results in a variable frequency wind energy generation system are shown.     

Sustainable electricity generation fuel mix analysis using an integration of multicriteria decision-making and system dynamic approach

To achieve a national energy access target of 90% urban and 51% rural by 2035, combat climate change, and diversify the energy sector in the country, the Zambian government is planning to integrate other renewable energy resources (RESs) such as wind, solar, biomass, and geothermal into the existing hydro generation–based power system. However, to achieve such targets, it is essential for the government to identify suitable combination of the RESs (electricity generation fuel mix) that can provide the greatest sustainability benefit to the country. In this paper, a multicriteria decision-making framework based on analytic hierarchy process and system dynamics techniques is proposed to evaluate and identify the best electricity generation fuel mix for Zambia. The renewable energy generation technologies considered include wind, solar photovoltaic, biomass, and hydropower. The criteria used are categorized as technical, economic, environmental, social, and political. The proposed approach was applied to rank the electricity generation fuel mix based on nine sustainability aspects: land use, CO₂ emissions, job creation, policy promotion affordability, subsidy cost, air pollution reduction, RES electricity production, RES cumulative capacity, and RES initial capital cost. The results indicate that based on availability of RESs and sustainability aspects, in overall, the best future electricity generation mix option for Zambia is scenario with higher hydropower (40%) penetration, wind (30%), solar (20%), and lower biomass (10%) penetration in the overall electricity generation fuel mix, which is mainly due to environmental issues and availability of primary energy resources. The results further indicate that solar ranks first in most of the scenarios even after the penetration weights of RES are adjusted in the sensitivity analysis. The wind was ranked second in most of the scenarios followed by hydropower and last was biomass. These developed electricity generation fuel mix pathways would enable the country meeting the future electricity generation needs target at minimized environmental and social impacts by 2035. Therefore, this study is essential to assist in policy and decision making including planning at strategic level for sustainable energy diversification.     

Reliability benefit analysis of adding WTG to a distribution system

Wind turbine generators (WTG) used as alternative supply in a distribution system have different impacts on the system reliability performance than conventional alternative supplies due to the variable wind speed. This paper investigates the system reliability benefits of adding WTG as alternative supply in a rural distribution system. The wind generation interrupted energy benefit (WGIEB), the wind generation interruption cost benefit (WGICB), the equivalent number of conventional generators (ENCG) and the equivalent conventional generator capacity (ECGC) of one MW WTG are introduced. These indices provide direct reliability benefit indicators on the addition of WTG, and are important information for system planners to make planning decisions such as the selection of a wind site and the number of WTG. A test rural distribution system is utilized to illustrate the proposed technique. The effects on the system reliability benefits of the wind site selection and the number of wind units are investigated     

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.     

世界风电产业发展综述

风力发电是目前最具商业化和市场竞争力的可再生能源技术。随着风电技术日趋成熟,风电产业在全球范围得到大力发展,并保持持续增长的势头。全世界风力资源丰富,风力发电将成为最重要的替代能源之一,但风电产业的发展受政策影响较大。文章阐述了世界风力发电产业的现状,分析了世界风电产业的发展趋势。     

Feasibility study of off-shore wind farms: an application to Puglia region

Recent environmental constraints and new secure technologies have enforced the development of comprehensive programmes for renewable energy. Wind energy is one of the most promising solutions, especially considering its technological advancements and its growth over the last years. In particular, off-shore wind energy is a key element in the EU White Paper target of 10% contribution of Renewable energy by 2010.In this paper, the technical and economical feasibility of off-shore wind farms is reviewed, in order to evaluate profitability and investment opportunities. In particular, a pre-feasibility study of off-shore wind farms to some selected sites in Puglia Region is provided. The study indicates the best sites in Puglia Region for off-shore plants. For each site, the cost of energy and the profitability of the investment are calculated. Moreover, in the most promising site, different wind turbine generators (WTGs) models are compared in order to evaluate the best performances. In the best site, which presents an average wind speed at 35 m height of 7.66 m/s, the cost of energy ranges between 5.2 and 6.0 c€/kWh. Moreover, the analysis shows that the use of large size WTGs allows reducing the cost of energy and increasing the profitability of the wind farm.     

An overview of the environmental,economic, and material developments of the solar and wind sources coupled with the energy storage systems

There is a constant growth in energy consumption and consequently energy generation around the world. During the recent decades, renewable energy sources took heed of scientists and policy makers as a remedy for substituting traditional sources. Wind and photovoltaic (PV) are the least reliable sources because of their dependence on wind speed and irradiance and therefore their intermittent nature. Energy storage systems are usually coupled with these sources to increase the reliability of the hybrid system. Environmental effects are one of the biggest concerns associated with the renewable energy sources. This study summarizes the last and most important environmental and economic analysis of a grid‐connected hybrid network consisting of wind turbine, PV panels, and energy storage systems. Focusing on environmental aspects, this paper reviews land efficiency, shaded analysis of wind turbines and PV panels, greenhouse gas emission, wastes of wind turbine and PV panels' components, fossil fuel consumption, wildlife, sensitive ecosystems, health benefits, and so on. A cost analysis of the energy generated by a hybrid system has been discussed. Furthermore, this study reviews the latest technologies for materials that have been used for solar PV manufacturing. This paper can help to make a right decision considering all aspects of installing a hybrid system. Copyright © 2017 John Wiley & Sons, Ltd.     

计及风电功率误差的短期风电消纳评估

风电功率的短时大幅变化会对电网的可靠性与经济性产生影响,为更加准确地量化评估电力系统在较短时间内的风电消纳状况,需要考虑风电功率预测的误差。为此,基于风电预测误差的分布与自相关函数,生成风电预测误差时间序列,通过模拟实际系统的发电计划制定、自动发电控制、弃风、切负荷,计算可靠性指标与经济性指标,以此评估短期风电消纳状况。在IEEE 30节点系统上进行了不同预测误差分布参数以及AGC机组占比的仿真,从而验证了所提方法的有效性。     

Estimating global hydrogen production from wind

It is likely that intermittent renewable sources such as wind and solar will provide the greatest opportunity for future large-scale hydrogen production. Here, on-shore wind is examined. Global wind energy is estimated by placing one 2 MW turbine/km² over the surface of the earth. Wind energy production is based on monthly mean wind speed data. Wind turbines are grouped to form arrays that are linked to local hydrogen generation and transmission networks. Hydrogen generation is done via low-pressure electrolysis and transmission via high-pressure gas pipelines. The wind/hydrogen system is considered within a global energy system that must not only provide hydrogen, but also energy for electricity consumption at the local generation site. The technical potential of the hydrogen produced is estimated to be 116 EJ. Uneven distribution of the hydrogen-rich sites results in the need to export much of the hydrogen produced to energy-poor regions. To overcome system losses, a combined wind/HVDC/hydrogen system is considered.     

How much wind energy will be curtailed on the 2020 Irish power system?

This paper describes a model of the 2020 Irish electricity system which was developed and solved in a mixed integer programming, unit commitment and economic dispatch tool called PLEXOS^®. The model includes all generators on the island of Ireland, a simplified representation of the neighbouring British system including proposed wind capacity and interconnectors between the two systems. The level of wind curtailment is determined under varying levels of three influencing factors. The first factor is the amount of offshore wind, the second is the allowed limit of system non-synchronous penetration (SNSP) and the third is inclusion or exclusion of transmission constraints. A binding constraint, resulting from the 2020 EU renewable energy targets, is that 37% of generation comes from wind. When the SNSP limit was increased from 60% to 75% there was a reduction in wind curtailment from 14% to 7%, with a further reduction when the proportion of wind capacity installed offshore was increased. Wind curtailment in the range of SNSP limit of 70–100% is influenced primarily by the inclusion of transmission constraints. Large changes in the dispatch of conventional generators were also evident due to the imposition of SNSP limits and transmission constraints.     

A review of power converter topologies for wind generators

Wind energy conversion systems have become a focal point in the research of renewable energy sources. This is in no small part due to the rapid advances in the size of wind generators as well as the development of power electronics and their applicability in wind energy extraction. This paper provides a comprehensive review of past and present converter topologies applicable to permanent magnet generators, induction generators, synchronous generators and doubly fed induction generators. The many different generator–converter combinations are compared on the basis of topology, cost, efficiency, power consumption and control complexity. The features of each generator–converter configuration are considered in the context of wind turbine systems.     

Modelling utility-scale wind power plants. Part 1: Economics

As the worldwide use of wind turbine generators continues to increase in utility-scale applications, it will become increasingly important to assess the economic and reliability impact of these intermittent resources. Although the utility industry in the United States appears to be moving towards a restructured environment, basic economic and reliability issues will continue to be relevant to companies involved with electricity generation. This article is the first of two which address modelling approaches and results obtained in several case studies and research projects at the National Renewable Energy Laboratory (NREL). This first article addresses the basic economic issues associated with electricity production from several generators that include large-scale wind power plants. An important part of this discussion is the role of unit commitment and economic dispatch in production cost models. This paper includes overviews and comparisons of the prevalent production cost modelling methods, including several case studies applied to a variety of electric utilities. The second article discusses various methods of assessing capacity credit and results from several reliability-based studies performed at NREL. Copyright © 1999 John Wiley & Sons, Ltd.     

Monitor system design of distributed wind turbine-energy storage system

风储互补配合是提高风电质量、增加风电可控性、解决风电并网问题的有效途径。本文对“一机一储”的分布式风储系统进行了分析,探讨了分布式风储系统设计的整体方案,对风储能量管理系统监控后台的数据记录、监控界面和报表生成等进行了功能设计。风储系统实际运行效果表明,该监控后台能够很好地实现监控显示、历史数据记录、运行模式设定、统计分析和报表生成等功能,系统运行可靠,可为风储系统的推广应用提供一定的参考。     

Lifetime and economic analyses of lithium‐ion batteries for balancing wind power forecast error

Wind power plant operators are often faced with extra charges when their power production does not match the forecasted power. Because the accuracy of wind power forecasts is limited, the use of energy storage systems is an attractive alternative even when large‐scale aggregation of wind power is considered. In this paper, the economic feasibility of lithium‐ion batteries for balancing the wind power forecast error is analysed. In order to perform a reliable assessment, an ageing model of lithium‐ion battery was developed considering both cycling and calendar life. The economic analysis considers two different energy management strategies for the storage systems and it is performed for the Danish market. Analyses have shown that the price of the Li‐ion BESS needs to decrease by 6.7 times in order to obtain a positive net present value considering the present prices on the Danish energy market. Moreover, it was found that for total elimination of the wind power forecast error, it is required to have a 25‐MWh Li‐ion battery energy storage system for the considered 2 MW WT. Copyright © 2015 John Wiley & Sons, Ltd.     

我国风力发电发展现状和问题分析

能源危机的日趋严重,优化能源结构、发展清洁环保的可再生能源迫在眉睫。风能是一种清洁环保的可再生能源,随着国家政策的支持和风力发电技术的不断发展,风力发电越来越得到人们的重视,并将在新能源发电中扮演重要的角色。概述了我国风能资源的储量和分布,介绍了近年来我国风力发电的总体情况、各省(自治区)风力发电的发展概况以及我国风电企业的发展现状,最后指出了我国风力发电目前出现的一些问题,并进行了分析。