Turbulent kinetic energy estimates from profiling wind LiDAR measurements and their potential for wind energy applications

This study shows that turbulent kinetic energy (TKE) estimates, derived from static LiDARs in Doppler Beam Swing (DBS) mode, permit a qualitative and quantitative characterization and analysis of turbulent structures as wind turbine wakes, and convective or shear generated eddies in the lower atmospheric boundary layer. The analysed data, collected by a WINDCUBE™ v1 in a wind park in Austria, is compared to WINDCUBE™ v1 and sonic data from the WINd Turbine Wake EXperiment Wieringermeer (WINTWEX-W). Although turbulence measurements with a WINDCUBE™ v1 are limited to a specific length scale, processed measurements above this threshold are in a good agreement with sonic anemometer data. In contrast to the commonly used turbulence intensity, the calculation of TKE not only provides an appropriate measure of turbulence intensities but also gives an insight into its origin. The processed data show typical wake characteristics, as flow decelerations, turbulence enhancement and wake rotation. By comparing these turbulence characteristics to other turbulent structures in the atmospheric boundary layer, we found that convection driven eddies in the surface layer have similar turbulence characteristics as turbine wakes, which makes convective weather situations relevant for wind turbine fatigue considerations.     

Wind energy and assessment of wind energy potential in Turkey

In this study, the potential of wind energy and assessment of wind energy systems in Turkey were studied. The main purpose of this study is to investigate the wind energy potential and future wind conversion systems project in Turkey. The wind energy potential of various regions was investigated; and the exploitation of the wind energy in Turkey was discussed. Various regions were analyzed taking into account the wind data measured as hourly time series in the windy locations. The wind data used in this study were taken from Electrical Power Resources Survey and Development Administration (EIEI) for the year 2010. This paper reviews the assessment of wind energy in Turkey as of the end of May 2010 including wind energy applications. Turkey's total theoretically available potential for wind power is around 131,756.40 MW and sea wind power 17,393.20 MW annually, according to TUREB (TWEA). When Turkey has 1.5 MW nominal installed wind energy capacity in 1998, then this capacity has increased to 1522.20 MW in 2010. Wind power plant with a total capacity of 1522.20 MW will be commissioned 2166.65 MW in December 2011.     

The role of hydrogen in high wind energy penetration electricity systems: The Irish case

The deployment of wind energy is constrained by wind uncontrollability, which poses operational problems on the electricity supply system at high penetration levels, lessening the value of wind-generated electricity to a significant extent. This paper studies the viability of hydrogen production via electrolysis using wind power that cannot be easily accommodated on the system. The potential benefits of hydrogen and its role in enabling a large penetration of wind energy are assessed, within the context of the enormous wind energy resource in Ireland. The exploitation of this wind resource may in the future give rise to significant amounts of surplus wind electricity, which could be used to produce hydrogen, the zero-emissions fuel that many experts believe will eventually replace fossil fuels in the transport sector. In this paper the operation of a wind powered hydrogen production system is simulated and optimised. The results reveal that, even allowing for significant cost-reductions in electrolyser and associated balance-of-plant equipment, low average surplus wind electricity cost and a high hydrogen market price are also necessary to achieve the economic viability of the technology. These conditions would facilitate the installation of electrolysis units of sufficient capacity to allow an appreciable increase in installed wind power in Ireland. The simulation model was also used to determine the CO₂ abatement potential associated with the wind energy/hydrogen production.     

Investigation of wind shear coefficients and their effect on electrical energy generation

Wind measurements are generally performed below wind turbine hub heights due to higher measurement and tower costs. In order to obtain the wind speed at the hub height of the turbine, the measurements are extrapolated, assuming that the wind shear is constant. This assumption may result in some critical errors between the estimated and actual energy outputs. In this paper wind data collected in Bal?kesir from October 2008 to September 2009, has been used to show the effects of wind shear coefficient on energy production. Results of the study showed that, the difference between wind energy production using extrapolated wind data and energy production using measured wind data at hub height may be up to 49.6%.     

Innovation and the price of wind energy in the US

In the last ten years, the wind energy industry has experienced many innovations resulting in wider deployment of wind energy, larger wind energy projects, larger wind turbines, and greater capacity factors. Using regression analysis, this paper examines the effects of technological improvements and other factors on the price of wind energy charged under long-term contracts in the United States. For wind energy projects completed during the period 1999–2006, higher capacity factors and larger wind farms contributed to reductions in wind energy contract prices paid by regulated investor owned utilities in 2007. However, this effect was offset by rising construction costs. Turbine size (in MW) shows no clear relationship to contract prices, possibly because there may be opposing factors tending to decrease costs as turbine size increases and tending to increase costs as turbine size increases. Wind energy is generally a low-cost resource that is competitive with natural gas-fired power generation.     

Effect of downwind swells on offshore wind energy harvesting – A large-eddy simulation study

The effect of ocean downwind swells on the harvesting of offshore wind energy is studied using large-eddy simulation of fully developed wind turbine array boundary layers, which is dynamically coupled with high-order spectral simulation of sea-surface wave field with and without the presence of a downwind swell. For the two moderate wind speeds of 7 m/s and 10 m/s considered in this study, the swell is found to induce a temporal oscillation in the extracted wind power at the swell frequency, with a magnitude of 6.7% and 4.0% of the mean wind power output, respectively. Furthermore, the averaged wind power extraction is found to be increased by as much as 18.8% and 13.6%, respectively. Statistical analysis of the wind field indicates that the wind speed in the lower portion of the boundary layer oscillates periodically with fast wind above the swell trough and slow wind above the swell crest, resulting in the observed wind power oscillation. The wind above the swell accelerates due to the strong wave forcing, causes a net upward flux of kinetic energy into the wind turbine layer, and thus acts to increase the extracted wind power of the turbines. For a high wind speed of 17 m/s, the wave-induced motion becomes relatively weak and the swell effect on the wind turbine performance diminishes.     

The wind potential impact on the maximum wind energy penetration in autonomous electrical grids

According to long-term wind speed measurements the Aegean Archipelago possesses excellent wind potential, hence properly designed wind energy applications can substantially contribute to fulfill the energy requirements of the island societies. On top of this, in most islands the electricity production cost is extremely high, while significant insufficient power supply problems are often encountered, especially during the summer. Unfortunately, the stochastic behaviour of the wind and the important fluctuations of daily and seasonal electricity load pose a strict penetration limit for the contribution of wind energy in the corresponding load demand. The application of this limit is necessary in order to avoid hazardous electricity grid fluctuations and to protect the existing thermal power units from operating near or below their technical minima. In this context, the main target of the proposed study is to present an integrated methodology able to estimate the maximum wind energy penetration in autonomous electrical grids on the basis of the available wind potential existing in the Aegean Archipelago area. For this purpose a large number of representative wind potential types have been investigated and interesting conclusions have been derived.     

Evaluation of electricity generation and energy cost of wind energy conversion systems (WECSs) in Central Turkey

The negative effects of non-renewable fossil fuels have forced scientists to draw attention to clean energy sources which are both environmentally more suitable and renewable. Although Turkey enjoys fairly high wind energy potential, an investigation and exploitation of this source is still below the desired level. In this study which is a preliminary study on wind energy cost in Central Anatolian-Turkey, the wind energy production using time-series approach and the economic evaluation of various wind energy conversion systems (WECSs) enjoying the 2.5, 5, 10, 20, 30, 50, 100 and 150 kW rated power size using the levelised cost of electricity (LCOE) method for the seven different locations in Central Turkey were estimated. In addition, effects of escalation ratio of operation and maintenance cost and annual mean speed on LCOE are taken into account. The wind speed data for a period between 2000 and 2006 years were taken from Turkish State Meteorological Service (TSMS). According to the result of the calculations, it is shown that the WECS of capacity 150 kW produce the energy output 120,978 kWh per year in the Case-A (Pinarbasi) for hub height 30 m and also the LCOE varies in the range of 0.29–30.0 $/kWh for all WECS considered.     

Electricity restructuring in Turkey and the share of wind energy production

This paper presents the current status of Turkey's electricity power sector, efforts for introducing competition in the Turkey's power industry, and concerns with the restructuring in Turkey. Turkey include long-term high-cost agreements, low quality of power, and therefore restrictions for synchronization with UCTE network, increase in the reliance on imported natural gas, and the urgent need for highly qualified staff that would be capable of fast and reliable implementation of ongoing reforms in the electricity sector. The contribution of the exploiting wind energy potential in Turkey to reconstruction of Turkey electricity structure is investigated. The strong development of wind energy in Turkey is expected to continue in the coming years.     

Potential wind power generation in the State of Kuwait

The wind characteristics of six locations in the State of Kuwait have been assessed. The annual average wind speed for the considered sites ranged from 3.7 to 5.5 m/s and a mean wind power density from 80 to 167 W/m² at standard height of 10 m. The Weibull parameters and power density of each station have been determined using Weibull distribution. The wind data at heights 15, 20, 25 and 30 m were obtained by extrapolation of the 10 m data using the Power-Law. The potential wind energy at different heights was estimated using Weibull parameters. Maximum power density is found at 30 m height which varies between 130 and 275 W/m² with 70% increase from the standard height indicating fairly potential wind energy especially in the northern part of the country. The highest potential wind power was found during the summer season which is the peak demand season of electricity in Kuwait.     

Evaluation of wind energy potential and electricity generation at six locations in Turkey

In this study, wind characteristics were analyzed using the wind speed data collected of the six meteorological stations in Turkey during the period 2000–2006. The annual mean wind speed of the six stations (Erzurum, Elaz??, Bingöl, Kars, Manisa and Ni?de) is obtained as 8.7, 8.5, 5.9, 6.9, 7.4 and 8.0 m/s at 10 m height, respectively. The mean annual value of Weibull shape parameter k is between 1.71 and 1.96 while the annual value of scale parameter c is between 6.81 and 9.71 m/s. A technical assessment has been made of electricity generation from four wind turbines having capacity of (600 kW, 1000 kW, 1500 kW and 2000 kW). The yearly energy output and capacity factor for the four different turbines were calculated.     

The current status of wind energy in Turkey and in the world

The rapid increase in world energy demand, the depletion of conventional energy sources and the pollution caused by conventional fuels have increased the importance of developing new and renewable energy sources. Additionally, technological developments have resulted in increased energy demand for the entire world, including Turkey, especially for electrical energy. At present, wind energy is receiving considerable attention. This report focuses on the current status of wind energy in Turkey and in the world. An overview of wind energy in Turkey is presented, and its current status, application, support mechanisms and associated legislation in Turkey are described. Wind energy and its status in the world are also addressed. It can be concluded from this analysis that wind energy utilization in Turkey and throughout world has sharply increased. Turkey has an abundance of wind energy sources.     

佳木斯风能资源形成分布探讨

风能资源是清洁的可再生能源,风能发电是新能源领域中技术最成熟、最具规模开发条件和商业化发展前景的发电方式之一,也是目前清洁能源中利用最方便、最快捷、最少投入的可再生能源之一。已经成为世界能源可持续发展战略的重要组成部分。因此本文从风的形成原因、影响风速大小的因素、佳木斯风能资源的分布状况和可建风电规模（发展目标）等方面予以阐述,为佳木斯的风电发展提供理论参考根据。     

Investigation of wind characteristics and wind energy potential in Kirklareli, Turkey

Utilization of wind energy as an energy source has been growing rapidly in the whole world due to environmental pollution, consumption of the limited fossil fuels and global warming. Although Turkey has fairly high wind energy potential, exploitation of the wind energy is still in the crawling level. In the current study, wind characteristics and wind energy potential of Kırklareli province in the Marmara Region, Turkey were analyzed taking into account the wind data measured as hourly time series. The wind data used in the study were taken from Electrical Power Resources Survey and Development Administration (EIEI) for the year 2004. The measured wind data were processed as annual, seasonal and monthly. Weibull and Rayleigh probability density functions of the location are calculated in the light of observed data and Weibull shape parameter k and scale parameter c are found as 1.75 and 5.25 m/s for the year 2004. According to the power calculations done for the site, annual mean power density based on Weibull function is 138.85 W/m². The results indicate that investigated site has fairly wind energy potential for the utilization.     

Public attitudes of wind energy in Texas: Local communities in close proximity to wind farms and their effect on decision-making

Wind energy is now recognized as an important energy resource throughout the world. Within the United States, the state of Texas currently has the largest wind energy capacity with 8797 total megawatts and an additional 660 MW under construction. With this rapid growth, it is important to achieve a better understanding of how wind energy is being perceived by the public.     

Growth and future trends of wind energy in India

In India, the wind power generation has gained a high level of attention and acceptability compared to other renewable energy technologies. New technological developments in wind power design have contributed for the significant advances in wind energy penetration and to get optimum power from available wind. The yearly percentage increase in wind energy installation is highest for India and now ranks fourth in the world with an installed capacity of 6018 MW. This paper reviews the development of wind energy in India and five potential Indian states. The future growth pattern and time period to achieve the technical wind potential are predicted and analysed.     

Developments in the utilisation of wind energy in Greece

The utilisation of renewable energy sources, and wind energy in particular, can be described in Greece as a story of high expectations, intense initial entrepreneurial interest, delays in the start-up phase of projects and, some times, disappointments during the implementation procedure. Still, the current situation gives reasons for some optimism. This paper provides a review of the present technological background in wind generators, as found in the Greek market, as well as a detailed analysis of the legislative framework. Moreover, it aims to analyse the development of the process of granting investment and production permissions and their implementation since 1999. Thus, it is possible to identify the main reasons for the problems that occurred since the liberalisation of the electricity market and to account for the interest in wind energy. Finally, comments and proposals are formulated concerning the hidden barriers, the pertinent problems and the promising perspectives of the use of wind energy in Greece.     

The present status and challenges of wind energy education and training in China

Wind energy has been identified in China as an important alternative energy source to balance its energy mix. By the end of 2012, wind power (2%) has surpassed nuclear power to become China's 3rd largest energy resource of electricity, only behind thermal power and hydropower. The rapid growth of China wind power industry in recent years has made China become the biggest market in the world. Meanwhile, it has created a big market for educational institutions to provide wind energy related education and training. The main objective of this study is to review current wind energy education and training in Chinese universities and training centers. Most of wind energy courses are provided by public universities because they have been accredited by Ministry of Education of China to offer students different options, including full-time and part-time degrees in Bachelor, Master or Ph.D. On-the-job training also has tremendous demand from the professionals who prefer short-term courses or on-site courses. Generally, the development of wind energy education and training lags behind the growth of wind power industry. Our study highlights the major opportunities and future challenges in China wind energy education and training.     

A joint probability density function of wind speed and direction for wind energy analysis

A very flexible joint probability density function of wind speed and direction is presented in this paper for use in wind energy analysis. A method that enables angular–linear distributions to be obtained with specified marginal distributions has been used for this purpose. For the marginal distribution of wind speed we use a singly truncated from below Normal–Weibull mixture distribution. The marginal distribution of wind direction comprises a finite mixture of von Mises distributions. The proposed model is applied in this paper to wind direction and wind speed hourly data recorded at several weather stations located in the Canary Islands (Spain). The suitability of the distributions is judged from the coefficient of determination R².

The conclusions reached are that the joint distribution proposed in this paper: (a) can represent unimodal, bimodal and bitangential wind speed frequency distributions, (b) takes into account the frequency of null winds, (c) represents the wind direction regimes in zones with several modes or prevailing wind directions, (d) takes into account the correlation between wind speeds and its directions. It can therefore be used in several tasks involved in the evaluation process of the wind resources available at a potential site. We also conclude that, in the case of the Canary Islands, the proposed model provides better fits in all the cases analysed than those obtained with the models used in the specialised literature on wind energy.