An actuator sector method for efficient transient wind turbine simulation

This paper investigates a new method for transient simulation of flow through a wind turbine using an actuator technique. The aim, in the context of wind turbine wake simulation, is to develop an alternative to the widely used actuator disc model with an increased resolution and range of applications, for the same or less computational expense. In this new model, the actuator sector method, forces applied to the fluid are distributed azimuthally to maintain a continuous flow solution for increased time‐step intervals compared with the actuator line method. Actuator sector results are presented in comparison with actuator disc and actuator line models initially for a non‐dimensionalized turbine in laminar onset flow. Subsequent results are presented for a turbine operating in a turbulent atmospheric boundary layer. Results show significant increases in flow fidelity compared with actuator disc model results; this includes the resolution of diametric variation in rotor loading caused by horizontal or vertical wind shear and the helical vortex system shed from the turbine blade tips. Significant reductions in computational processing time were achieved with wake velocities and turbulence statistics comparable with actuator line model results. The actuator sector method offers an improved alternative to applications employing conventional actuator disc models, with little or no additional computational cost. This technique in conjunction with a Cartesian mesh‐based parallel flow solver leads to efficient simulation of turbines in atmospheric boundary layer flows. Copyright © 2014 John Wiley & Sons, Ltd.     

Simulation of electricity supply of an Atlantic island by offshore wind turbines and wave energy converters associated with a medium scale local energy storage

The problem of sizing an electricity storage for a 5000 inhabitants island supplied by both marine renewables (offshore wind and waves) and the mainland grid is addressed by a case study based on a full year resource and consumption data. Generators, transmission lines and battery storage are accounted for through basic simplified models while the focus is put on electricity import/export budget. Self-sufficiency does not seem a reasonable goal to pursue, but partial autonomy provided by renewable sources and a medium size storage would probably be profitable to the island community.     

An Assessment of Wind Turbine Characteristics and Wind Energy Characteristics for Electricity Production

This work is an analysis of wind turbine characteristics and wind energy characteristics of four regions around Elazig, Turkey, namely Maden, Agin Elazig and Keban. Wind speed data and wind direction in measured hourly time-series format is statistically analyzed based on 6 years between 1998 and 2003. The probability density distributions are derived from time-series data and distributional parameters are identified. Two probability density functions are fitted to the measured probability distributions. The wind energy characteristic of all the regions is studied based on the Weibull and the Rayleigh distributions. Using the Weibull probability density function, we estimated the wind energy output and the capacity factor for six different wind turbines between 300 and 2300 kW during the six years. It was found that Maden is the best region, among the regions analyzed, for wind energy characteristic and wind turbine characteristic.     

LARGE WIND TURBINES: A EUROPEAN COORDINATED DEVELOPMENT PROGRAMME

At the present time, the commercial use of wind energy for electricity production is based on series produced wind energy turbines with power ratings up to approximately 500 kW. In a good wind regime turbines of this kind can achieve energy production costs near to conventional generating costs. Very large wind energy conveners in the megawatt range have been under development for about 15 years, but as yet their commercial contribution is small.

The European Commission has taken a coordinated initiative to support the development of large wind turbines in the Megawatt power range. In the R&D programmes JOULE and THERMIE a variety of projects are being developed and demonstrated. The aim is the availability of economic large wind turbines for commercial application.     

我国的风电技术和风电发展

发展风力发电是我国能源战略的一项重要内容.文章首先介绍了我国风电利用的总体状况;然后从风机叶片制造、控制系统及整机制造等方面,详述了现阶段我国风电设备的基本状况;最后对我国风电发展障碍进行了分析,并提出了相关建议.     

广东省周边海域风能和波浪能联合开发潜力分析

参考现有海上风电场位置选择广东省周边海域的5处联合开发场址,基于2001—2020年的风和波浪再分析数据,从资源储量和稳定性等角度对选址开展资源特征的详细分析,并评估不同额定功率的6种风力机和6种波浪能装置在选址处的发电性能。结果表明,广东省周边海域的风能和波浪能均有明显的季节分布差异,在秋冬季节更为丰富且更为稳定;风能和波浪能具有较强的相关性;风力机额定功率越大平均发电功率越大,但容量因数随额定功率的增大呈现波动趋势;风力机的容量因数明显大于波浪能装置;综合考虑多种因素,W2E-215/9.0风力机和Wave Star波浪能装置更适合投放于所提5处场址。     

海上风力发电进展

近年来风力发电工业发展迅速，海上风能以其突出的优势受到重视。本文对近年来国外几种典型的海上风能资源评估方法做出述评，简要叙述了国外海上风电技术发展与应用的现状，分析了海上风能利用的经济性，并介绍了一些主要国家进一步发展海上风电的计划。     

Design of an energy hub based on natural gas and renewable energy sources

This paper presents a simulation model for an energy hub consisting of natural gas (NG) turbines as the main sources of energy (including both electricity and heat) and two renewable energy sources—wind turbines (WTs) and photovoltaic (PV) solar cells. The hub also includes water electrolyzers for hydrogen production. The hydrogen serves as an energy storage medium that can be used in some transportation applications, or it can be mixed with the NG feed stream to improve the emission profile of the gas‐turbine unit. The capacity of the designed hub is meant to simulate and replace the coal‐fired Nanticoke Generating Station with a NG‐fired power plant. Therefore, the aim of this work is to develop a simulated model that combines different energy generation technologies, which are evaluated in terms of the total energy produced, the cost per kWh of energy generated, and the amount of emissions produced. The proposed model investigates the benefits, both economic and environmental, the technological barriers, and the challenges of energy hubs by developing several scenarios. The simulation of these scenarios was done using General Algebraic Modeling System (GAMS®). Although the software is strongly known for its optimization capability, the mixed complementary problems solver makes it a strong tool for solving equilibrium problems. Excess energy produced during off‐peak demand by WTs and PV solar cells was used to feed the electrolyzer to produce H₂ and O₂. The proposed approach shows that a significant reduction in energy cost and greenhouse gas emissions were achieved, in addition to the increased overall efficiency of the energy hub. Out of the examined three scenarios, Scenario C appeared to be the most feasible option for a combination of renewable and non‐renewable technologies as it did not only produce hydrogen, but also provided electricity at relatively lower prices. Copyright © 2013 John Wiley & Sons, Ltd.     

Offshore wind energy in the world context

The interest for the exploitation of the offshore wind energy is growing in Europe, where man land use is very high resulting in strong limitation to the installation of onshore wind farms. The today offshore operating wind power is 12 MW, with two wind farms in Denmark and one in Netherlands; it starts to be significant (0.6%) in terms of the onshore power, 2000 MW in Europe.In the world the onshore installed wind power is exceeding 4000 MW, but not so much up to now has been done on the offshore area outside Europe.The European four years experience on the prototypical offshore wind farms looks significantly promising and suggests to promote a similar approach in many densely populated coastal countries in the world with high electricity demand.Results of studies are presented on the offshore wind potential in the European countries and of the tentative evaluation for the Mediterranean basin, and the seas of USA and China. A review is made of the offshore applications, particularly for the Nothern European seas.Economy and environmental trends are illustrated in parallel to those of maturing offshore technology. It is suggested to prepare an action plan to promote the development of the offshore applications in the world context.     

Techno-economic feasibility of fleets of far offshore hydrogen-producing wind energy converters

Innovative solutions need to be developed for harvesting wind energy far offshore. They necessarily involve on-board energy storage because grid-connection would be prohibitively expensive. Hydrogen is one of the most promising solutions. However, it is well-known that it is challenging to store and transport hydrogen which may have a critical impact on the delivered hydrogen cost.In this paper, it is shown that there are vast areas far offshore where wind power is both characterized by high winds and limited seasonal variations. Capturing a fraction of this energy could provide enough energy to cover the forecast global energy demand for 2050. Thus, scenarios are proposed for the exploitation of this resource by fleets of hydrogen-producing wind energy converters sailing autonomously. The scenarios include transportation and distribution of the produced hydrogen.The delivered hydrogen cost is estimated for the various scenarios in the short term and in the longer term. Cost estimates are derived using technical and economic data available in the literature and assumptions for the cost of electricity available on-board the wind energy converters. In the shorter term, delivered cost estimates are in the range 7.1–9.4 €/kg depending on the scenario and the delivery distance. They are based on the assumption of on-board electricity cost at 0.08€/kWh. In the longer term, assuming an on-board electricity cost at 0.04€.kWh, the cost estimates could reduce to 3.5 to 5.7 €/kg which would make the hydrogen competitive on several hydrogen markets without any support mechanism. For the hydrogen to be competitive on all hydrogen markets including the ones with the highest GHG emissions, a carbon tax of approximately 200 €/kg would be required.     

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.     

Turbulent times: tourists’ attitudes towards wind turbines in the Southern Highlands in Iceland

As a response to the threat of climate change, many nations are increasing their use of renewable energy, including wind energy. Large wind farms often conflict with other land uses, particularly tourism, which is a growing industry worldwide. In Iceland, tourism has recently become the largest export sector, with majority of tourists travelling to the country to experience its nature. This paper examines tourists’ opinions and perceptions of wind power development in the Southern Highlands of Iceland and compares how number, size and proximity of wind turbines, and the landscape in which they are situated, influence tourists’ perceptions. The study is based on an on-site questionnaire survey conducted in 2015. The results indicate that one-third of the travellers would be less likely to visit the Southern Highlands if a proposed wind farm were built, and two-thirds think that wind turbines would decrease the area’s attractiveness.     

Control of variable‐speed wind turbines by LPV gain scheduling

This article considers gain‐scheduling control of variable‐speed wind energy conversion systems (WECS) in the context of linear parameter‐varying (LPV) systems. The typical problems of the classic gain‐scheduling techniques, such as stability guarantees, undesirable transient responses in the controller commutations and arduous design procedures, can be avoided with this new formulation. A model of a variable‐speed WECS expressed in LPV form and an optimal LPV gain‐scheduling control strategy are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

Dynamic models of wind farms with fixed speed wind turbines

The increasing wind power penetration on power systems requires the development of adequate wind farms models for representing the dynamic behaviour of wind farms on power systems. The behaviour of a wind farm can be represented by a detailed model including the modelling of all wind turbines and the wind farm electrical network. But this detailed model presents a high order model if a wind farm with high number of wind turbines is modelled and therefore the simulation time is long. The development of equivalent wind farm models enables the model order and the computation time to be reduced when the impact of wind farms on power systems is studied. In this paper, equivalent models of wind farms with fixed speed wind turbines are proposed by aggregating wind turbines into an equivalent wind turbine that operates on an equivalent wind farm electrical network. Two equivalent wind turbines have been developed: one for aggregated wind turbines with similar winds, and another for aggregated wind turbines under any incoming wind, even with different incoming winds.The proposed equivalent models provide high accuracy for representing the dynamic response of wind farm on power system simulations with an important reduction of model order and simulation time compare to that of the complete wind farm modelled by the detailed model.     

Hybrid systems for decentralized power generation in Oman

The main objective of this study is to determine the optimum size of systems able to fulfil the electrical energy requirements of remote sites located in Hajer Bani (HB) Hameed in the North of Oman, Masirah Island and the Mothorah area in the South of Oman. The methodology applied provides a useful and simple approach for sizing and analysing the hybrid systems using Hybrid Optimization Model for Electric Renewables (HOMER). The aim is to identify a configuration among a set of systems that meet the desired system reliability requirements with the lowest energy cost. The results of the analysis are a list of feasible power supply systems, classified according to their net present cost. Actual hourly load data are taken from these sites and are used in the model, and the meteorological readings are used either from the same site or from a nearby one. A comparison between the costs of electricity generated from renewable energy resources in these locations is done and the payback period for renewable energy components is calculated. Moreover, the effects of the temperature on the photovoltaic cells efficiency and energy cost are considered. The cost of energy was found to be 0.206, 0.361 and 0.327 $/kWh for Masirah Island, Mothorah and HB Hameed, respectively.