Journal of Wind Energy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Combining Wind and Pumped Hydro Energy Storage for Renewable Energy Generation in Ireland Thu, 21 Aug 2014 06:01:44 +0000 http://www.hindawi.com/journals/jwe/2014/415898/ Ireland has one of the highest wind energy potentials in Europe. The intermittent nature of wind makes this renewable resource impractical as a sole source of energy. Combining wind energy with pumped hydro energy storage (PHES) can overcome this intermittency, consuming energy during low-demand periods and supplying energy for periods of high demand. Currently Ireland has a number of hydroelectric power plants and wind farms of various scales in operation. A feasibility study was conducted to investigate the potential of securing a reliable source of renewable energy by increasing the penetration of hydroelectric power by means of combined wind-PHES developments. The greatest wind potential is experienced along the western coast of Ireland and a number of sites were identified here which satisfied a minimum mean wind speed criterion of 10.5 ms−1. Each site was then further evaluated according to topographical requirements for PHES. All but two of the identified sites are immediately unsuitable due to the presence of areas protected under European legislation; this highlights the nonenergy related obstacles in the path of renewable energy generation in Ireland and suggests that a compromise should be researched which could facilitate both renewable energy generation and species and habitat protection in Europe. Alice Coburn, Eilín Walsh, Patrick J. Solan, and Kevin P. McDonnell Copyright © 2014 Alice Coburn et al. All rights reserved. A New Hybrid Forecasting Strategy Applied to Mean Hourly Wind Speed Time Series Thu, 12 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/jwe/2014/683939/ An alternative electric power source, such as wind power, has to be both reliable and autonomous. An accurate wind speed forecasting method plays the key role in achieving the aforementioned properties and also is a valuable tool in overcoming a variety of economic and technical problems connected to wind power production. The method proposed is based on the reformulation of the problem in the standard state space form and on implementing a bank of Kalman filters (KF), each fitting an ARMA model of different order. The proposed method is to be applied to a greenhouse unit which incorporates an automatized use of renewable energy sources including wind speed power. Stylianos Sp. Pappas, Dimitrios Ch. Karamousantas, George E. Chatzarakis, and Christos Sp. Pappas Copyright © 2014 Stylianos Sp. Pappas et al. All rights reserved. Observation of the Starting and Low Speed Behavior of Small Horizontal Axis Wind Turbine Thu, 05 Jun 2014 08:48:51 +0000 http://www.hindawi.com/journals/jwe/2014/527198/ This paper describes the starting behavior of small horizontal axis wind turbines at high angles of attack and low Reynolds number. The unfavorable relative wind direction during the starting time leads to low starting torque and more idling time. Wind turbine models of sizes less than 5 meters were simulated at wind speed range of 2 m/s to 5 m/s. Wind turbines were modeled in Pro/E and based on the optimized designs given by MATLAB codes. Wind turbine models were simulated in ADAMS for improving the starting behavior. The models with high starting torques and less idling times were selected. The starting behavior was successfully improved and the optimized wind turbine models were able to produce more starting torque even at wind speeds less than 5 m/s. Sikandar Khan, Kamran Shah, Izhar-Ul-Haq, Hamid Khan, Sajid Ali, Naveed Ahmad, Muhammad Abid, Haider Ali, Ihsanullah, and Mazhar Sher Copyright © 2014 Sikandar Khan et al. All rights reserved. On the Deflexion of Anisotropic Structural Composite Aerodynamic Components Mon, 20 Jan 2014 13:57:19 +0000 http://www.hindawi.com/journals/jwe/2014/987414/ This paper presents closed form solutions to the classical beam elasticity differential equation in order to effectively model the displacement of standard aerodynamic geometries used throughout a number of industries. The models assume that the components are constructed from in-plane generally anisotropic (though shown to be quasi-isotropic) composite materials. Exact solutions for the displacement and strains for elliptical and FX66-S-196 and NACA 63-621 aerofoil approximations thin wall composite material shell structures, with and without a stiffening rib (shear-web), are presented for the first time. Each of the models developed is rigorously validated via numerical (Runge-Kutta) solutions of an identical differential equation used to derive the analytical models presented. The resulting calculated displacement and material strain fields are shown to be in excellent agreement with simulations using the ANSYS and CATIA commercial finite element (FE) codes as well as experimental data evident in the literature. One major implication of the theoretical treatment is that these solutions can now be used in design codes to limit the required displacement and strains in similar components used in the aerospace and most notably renewable energy sectors. J. Whitty, T. Haydock, B. Johnson, and J. Howe Copyright © 2014 J. Whitty et al. All rights reserved. Influences of Wind Energy Integration into the Distribution Network Mon, 11 Nov 2013 13:42:41 +0000 http://www.hindawi.com/journals/jwe/2013/903057/ Wind energy is one of the most promising renewable energy sources due to its availability and climate-friendly attributes. Large-scale integration of wind energy sources creates potential technical challenges due to the intermittent nature that needs to be investigated and mitigated as part of developing a sustainable power system for the future. Therefore, this study developed simulation models to investigate the potential challenges, in particular voltage fluctuations, zone substation, and distribution transformer loading, power flow characteristics, and harmonic emissions with the integration of wind energy into both the high voltage (HV) and low voltage (LV) distribution network (DN). From model analysis, it has been clearly indicated that influences of these problems increase with the increased integration of wind energy into both the high voltage and low voltage distribution network; however, the level of adverse impacts is higher in the LV DN compared to the HV DN. G. M. Shafiullah, Amanullah M. T. Oo, A. B. M. Shawkat Ali, and Alex Stojcevski Copyright © 2013 G. M. Shafiullah et al. All rights reserved. Electric Control Substituting Pitch Control for Large Wind Turbines Wed, 18 Sep 2013 11:58:52 +0000 http://www.hindawi.com/journals/jwe/2013/342061/ A completely electrical control of a variable speed wind turbine is experimentally verified. A vertical axis wind turbine with a direct driven generator and an electrical system with diode rectification and full inverter connected to the electric grid is presented. This is the first paper that presents this novel 200 kW wind power plant erected at the west coast of Sweden. The turbine has fixed pitch and is only controlled electrically accommodated by passive stall of the blades. By electrically controlling the generator rotational speed with the inverter, passive stall regulation is enabled. The first results on experimental verification of stall regulation in gusty wind speeds are presented. The experiments show that the control system can keep the turbine rotational speed constant even at very gusty winds. It is concluded that electrical control accommodated by passive stall is sufficient as control of the wind turbine even at high wind speeds and can substitute mechanical control such as blade pitch. Jon Kjellin, Sandra Eriksson, and Hans Bernhoff Copyright © 2013 Jon Kjellin et al. All rights reserved. Prospects of Wind-Diesel Generator-Battery Hybrid Power System: A Feasibility Study in Algeria Mon, 26 Aug 2013 13:11:34 +0000 http://www.hindawi.com/journals/jwe/2013/413425/ The present work analyses the feasibility of a wind-diesel generator-battery hybrid system. The wind energy resource data are collected from the weather station at the Renewable Energy Development Center of Bouzareah in Algeria. The recorded values vary from 5.5 m/s to 7 m/s at 25 m. The hybrid system analysis has shown that for a household consuming 1,270 kWh/yr, the cost of energy is 1.205 USD/kWh and produces 2,493 kWh/yr in which 93% of electricity comes from wind energy. From this study, it is clear that the optimized hybrid system is more cost effective compared to the diesel generator system alone where the NPC and COE are equal, respectively, to 19,561 USD and 1.205 USD/kWh and 47,932 USD and 2.952 USD/kWh. The sensitivity analysis predicts that the grid extension distance varies from 1.25 to 1.85 km depending on wind speed and fuel price which indicate a positive result to implement a stand-alone hybrid power system as an alternative to grid extension. In addition to the feasibility of this system, it can reduce the emission of the CO2, SO2, and NOx, respectively, from 4758 to 147, from 9.45 to 0.294, and from 105 to 3.23 kg/yr. Investments in autonomous renewable energy systems should be considered particularly in remote areas. They can be financed in the framework of the National Energy Action Plan of Algeria. Djohra Saheb-Koussa, Mustapha Koussa, and Nourredine Said Copyright © 2013 Djohra Saheb-Koussa et al. All rights reserved. Power Generation Expansion Planning Including Large Scale Wind Integration: A Case Study of Oman Wed, 17 Jul 2013 10:27:05 +0000 http://www.hindawi.com/journals/jwe/2013/735693/ Many options can be effectively used to meet the future power needs of a country in ways which would be more economically viable, environmentally sound, and socially just. A least-cost generation expansion planning study is conducted to find the economic feasibility of large scale integration of wind farms in the main interconnected transmission system of Oman. The generation expansion planning software used is WASP which is restricted in its ability to model intermittent nature of wind. Therefore, a wind turbine is modeled as a thermal plant with high forced outage rate related to its capacity factor. The result of the study has shown that wind turbines are economically viable option in the overall least-cost generation expansion plan for the Main Interconnected System of Oman. Arif S. Malik and Cornelius Kuba Copyright © 2013 Arif S. Malik and Cornelius Kuba. All rights reserved. Statistical and Spectral Analysis of Wind Characteristics Relevant to Wind Energy Assessment Using Tower Measurements in Complex Terrain Wed, 10 Jul 2013 11:11:13 +0000 http://www.hindawi.com/journals/jwe/2013/739162/ The main objective of the study was to investigate spatial and temporal characteristics of the wind speed and direction in complex terrain that are relevant to wind energy assessment and development, as well as to wind energy system operation, management, and grid integration. Wind data from five tall meteorological towers located in Western Nevada, USA, operated from August 2003 to March 2008, used in the analysis. The multiannual average wind speeds did not show significant increased trend with increasing elevation, while the turbulence intensity slowly decreased with an increase were the average wind speed. The wind speed and direction were modeled using the Weibull and the von Mises distribution functions. The correlations show a strong coherence between the wind speed and direction with slowly decreasing amplitude of the multiday periodicity with increasing lag periods. The spectral analysis shows significant annual periodicity with similar characteristics at all locations. The relatively high correlations between the towers and small range of the computed turbulence intensity indicate that wind variability is dominated by the regional synoptic processes. Knowledge and information about daily, seasonal, and annual wind periodicities are very important for wind energy resource assessment, wind power plant operation, management, and grid integration. Radian Belu and Darko Koracin Copyright © 2013 Radian Belu and Darko Koracin. All rights reserved.