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.     

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.     

Design and implementation of wind energy system in Saudi Arabia

This paper introduces an accurate procedure to choose the best site from many sites and suitable wind turbines for these sites depending on the minimum price of kWh generated (Energy Cost Figure (ECF)) from wind energy system. In this paper a new proposed computer program has been introduced to perform all the calculations and optimization required to accurately design the wind energy system and matching between sites and wind turbines. Some of cost calculations of energy methods have been introduced and compared to choose the most suitable method. The data for five sites in Saudi Arabia and hundred wind turbines have been used to choose the best site and the optimum wind turbine for each site. These sites are Yanbo, Dhahran, Dhulom, Riyadh, and Qaisumah. One hundred wind turbines have been used to choose the best one for each site. This program is built in a generic form which allows it to be used with unlimited number of sites and wind turbines in all over the world. The program is written by using Visual Fortran and it is verified with simple calculation in Excel. The paper showed that the best site is Dhahran and the suitable wind turbine for this site is KMW-ERNO with 5.85 Cents/kWh. The worst site to install wind energy system is Riyadh with minimum price of kWh of 12.81 Cents/kWh in case of using GE Energy 2 wind turbine.     

Wind characteristics and wind energy potential in Morocco

The wind characteristics of 11 sites in the windy regions in Morocco have been analysed. The annual average wind speed for the considered sites ranged from 5 m/s to 10 m/s and the average power density from 100 W/m² to 1000 W/m², which might be suitable for electrical power production by installing wind farms. On an annual scale the observations of the distribution of hourly wind speed are better fitted by the Weibull hybrid distribution in contrast to the Weibull distribution.The wind power is estimated to be 1817 MW, that is to say, the exploitable wind energy is 15198 GWh, which represents theoretically 11% of the total consumed energy in Morocco in 1994.     

A simplified model for estimating yearly wind fraction in hybrid-wind energy systems

This article presents a simplified algorithm to estimate the yearly wind fraction, the fraction of energy demand provided by wind generator, in a hybrid-wind system (typically a PV-wind) with battery storage. The novel model is drawn based on the simulation results, using 8-year long measured hour-by-hour wind speed data from five different locations throughout the world. The simulation program simulates the battery state of voltage (SoV) and is able to predict the wind fraction for a period of time, typically monthly or yearly. The yearly wind fraction values obtained from the simulations are plotted against the ratio of energy to load for various battery storage capacities to obtain wind fraction curves. The novel method correlates the yearly wind fraction with the parameters of the Weibull distribution function, thus, offering a general methodology. The yearly wind fraction curves are mathematically represented using a 2-parameter model. The novel algorithm is validated by comparing the simulated wind fraction values with those calculated from the simplified algorithm. The standard error of estimation of the WF from the simplified algorithm is further presented for each battery capacity.     

Cost effectiveness of decentralized energy supply systems taking solar and wind utilization plants into account

In this article, results are presented of annual simulations of a decentralized (regional) plant for the power and heat supply of a residential complex. This complex consists of four houses with 40 flats all in all. The annual power consumption of the complex is 157 MWh and the heat requirement is 325 MWh. The concrete dynamics of the energy demands over the year is taken into consideration. The energy supply system is composed of a power-controlled combined heat and power (CHP) plant (55 kW), a photovoltaic plant (PV array or PV plant) array for power generation as well as a field of solar thermal collectors with a short-term accumulator for water heating and a long-term accumulator for supplying heat for domestic heating purposes. Simulation results demonstrate that synergetic effects result from the combination of a CHP plant with wind power and PV plants of varying sizes, which have an effect on the cost effectiveness of the plant as a whole with the different dynamics of energy sources (wind and solar energies) and of the consumption of power and heat being the decisive factors. The power deficits of wind power and PV plants are compensated through the application of a natural gas-operated CHP plant. In almost all variants, the demand for fossil energy carriers is distinctly less than in conventional energy supply plants.     

The potential for wind energy in Britain

This paper discusses the prospects for the large-scale use of wind power for electricity supply in Britain. Recent economic advances in wind energy are outlined, and it is shown that on windy sites, currently-available machines are among the cheapest generating options. The results from detailed studies of wind energy resources, and of the long-term integration of wind power on the UK supply system, are then summarized. These studies are applied together in probabilistic projections of wind energy and power system costs. Results suggest that, siting permitting, the economic long-term contribution of wind energy in Britain is likely to lie in the range of 20–50% of system demand. The most critical questions for wind development now relate to institutional issues and the desirability of the source on such scales.     

Assessment of wind energy in Iran: A review

In this study, a ten minute period measuring wind speed data for year 2007 at 10 m, 30 m and 40 m heights for different places in Iran, has been statistically analyzed to determine the potential of wind power generation. Sixty eight sites have been studied. The objective is to evaluate the most important characteristics of wind energy in the studied sites. The statistical attitudes permit us to estimate the mean wind speed, the wind speed distribution function, the mean wind power density and the wind rose in the site at three different heights. Some local phenomena are also considered in the characterization of the site.     

Economic analysis of wind-generated electricity in remote areas of South Africa

Costs of wind-generated electricity from a stand-alone wind generator with a two-day autonomous battery storage are compared with costs of diesel-generated and grid electricity for a remote outpost in a game reserve in South Africa. Comparative inflationary costs for diesel and wind were 53 and 33c/kWh, respectively. The cost of connecting to the national electricity grid were estimated to be 248c/kWh. Analysis of the availability of the wind and related power output of a selected wind generator revealed that the wind speeds fell between cut-in and cut-out speeds for approximately 80% of the time. In the light of the positive nature of these preliminary computations it is contended that a combined wind-diesel system, in which the diesel would act as backup storage, would be an economically viable mode of electricity generation in a remote area.     

Designing an index for assessing wind energy potential

To meet the increasing global demand for renewable energy, such as wind energy, an increasing number of wind parks are being constructed worldwide. Finding a suitable location requires a detailed and often costly analysis of local wind conditions. Plain average wind speed maps cannot provide a precise forecast of wind power because of the non-linear relationship between wind speed and production. We suggest a new approach to assess the local wind energy potential. First, meteorological reanalysis data are applied to obtain long-term low-scale wind speed data at specific turbine locations and hub heights. Second, the relation between wind data and energy production is determined via a five parameter logistic function using actual high-frequency energy production data. The resulting wind energy index allows for a turbine-specific estimation of the expected wind power at an unobserved location. A map of the wind power potential for Germany exemplifies our approach.     

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.     

Uncertainty analysis of wind energy potential assessment

This study presents a framework to assess the wind resource of a wind turbine using uncertainty analysis. Firstly, probability models are proposed for the natural variability of wind resources that include air density, mean wind velocity and associated Weibull parameters, surface roughness exponent, and error for prediction of long-term wind velocity based on the Measure–Correlate–Predict method. An empirical probability model for a power performance curve is also demonstrated. Secondly, a Monte-Carlo based numerical simulation procedure which utilizes the probability models is presented. From the numerical simulation, it is found that the present method can effectively evaluate the expected annual energy production for different averaging periods and confidence intervals. The uncertainty, which is 11% corresponding to the normalized average energy production in the present example, can be calculated by specifically considering the characteristics of the individual sources in terms of probability parameters.     

Estimation of wind energy potential using different probability density functions

In addition to the probability density function (pdf) derived with maximum entropy principle (MEP), several kinds of mixture probability functions have already been applied to estimate wind energy potential in scientific literature, such as the bimodal Weibull function (WW) and truncated Normal Weibull function (NW). In this paper, two other mixture functions are proposed for the first time to wind energy field, i.e. the mixture Gamma–Weibull function (GW) and mixture truncated normal function (NN). These five functions will be reviewed and compared together with conventional Weibull function. Wind speed data measured from 2006 to 2008 at three wind farms experiencing different climatic environments in Taiwan are selected as sample data to test their performance. Judgment criteria include four kinds of statistical errors, i.e. the max error in Kolmogorov–Smirnov test, root mean square error, Chi-square error and relative error of wind potential energy. The results show that all the mixture functions and the maximum entropy function describe wind characterizations better than the conventional Weibull function if wind regime presents two humps on it, irrespective of wind speed and power density. For wind speed distributions, the proposed GW pdf describes best according to the Kolmogorov–Smirnov test followed by the NW and WW pdfs, while the NN pdf performs worst. As for wind power density, the MEP and GW pdfs perform best followed by the WW and NW pdfs. The GW pdf could be a useful alternative to the conventional Weibull function in estimating wind energy potential.     

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.     

Analysis of wind climate and wind energy potential of regions in Turkey

Investments in wind plants have increased rapidly as a result of changes to legal regulations in Turkey over the last five years. This has also led to an increase in the number of wind potential analyses in various regions of the country. This study analyzes the wind climate features of three regions in Turkey and their energy potential. In order to determine the features of wind in these regions, a five-layer Sugeno-type ANFIS model established under the MATLAB-Simulink software was used and the relationship between wind speed and other climate variables determined. In the second phase, WASP software was used to complete the wind energy potential analyses using wind speed data. The final phase includes calculations of the amount of electricity to be obtained technically and capacity usage rates of the installed turbines if wind farms are established in the selected areas. The comparative tables and graphics of the said areas were obtained. In conclusion, the selected areas are well located for the installation of parallel-connected wind plants to the national network in terms of the reliability of wind, the dispersion of wind potential and capacity usage rates.     

Optimisation and techno-economic analysis of autonomous photovoltaic–wind hybrid energy systems in comparison to single photovoltaic and wind systems

A techno-economic analysis for autonomous small scale photovoltaic–wind hybrid energy systems is undertaken for optimisation purposes in the present paper. The answer to the question whether a hybrid photovoltaic–wind or a single photovoltaic or wind system is techno-economically better is also sought. Monthly analysis of 8 year long measured hourly weather data shows that solar and wind resources vary greatly from one month to the next. The monthly combinations of these resources lead to basically three types of months: solar-biased month, wind-biased month and even month. This, in turn, leads to energy systems in which the energy contributions from photovoltaic and wind generators vary greatly. The monthly and yearly system performances simulations for different types of months show that the system performances vary greatly for varying battery storage capacities and different fractions of photovoltaic and wind energy. As well as the system performance, the optimisation process of such hybrid systems should further consist of the system cost. Therefore, the system performance results are combined with system cost data. The total system cost and the unit cost of the produced electricity (for a 20 year system lifetime) are analysed with strict reference to the yearly system performance. It is shown that an optimum combination of the hybrid photovoltaic–wind energy system provides higher system performance than either of the single systems for the same system cost for every battery storage capacity analysed in the present study. It is also shown that the magnitude of the battery storage capacity has important bearings on the system performance of single photovoltaic and wind systems. The single photovoltaic system performs better than a single wind system for 2 day storage capacity, while the single wind system performs better for 1.25 day storage capacity for the same system cost.     

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.     

Wind energy potential assessment for the Sultanate of Oman

Wind data analysis for the Sultanate of Oman is carried out in this study. The results are presented mainly in the form of contour maps, in addition to tabulated data and figures for average wind speed and direction as well as wind availability and power density spanning a period of ten years. The analysis covers diurnal, seasonal and height variations on wind parameters. The data used in the analysis were obtained from NASA Langley Research Center. This analysis provides a needed reference for the spatial distribution of wind characteristics for the whole of Oman from which possible locations for the deployment of wind-based energy conversion systems may be identified.     

Economic assessment of the engineering basis for wind power: Perspective of a vertically integrated utility

If wind park configurations are globally coordinated across the service area of a power utility, then electricity can be generated for the grid with substantial cost advantages. Based on this premise, the paper introduces a model by which large scale assessment of grid connected wind based power generation may be undertaken for a utility service area. The model can be useful to the policy maker for decisions regarding suitable wind portfolio standards (WPS) definition. The utility on the other hand, may use the model to study its service area for prospective wind based generation. Aspects of the problem modelled include cost-of-energy from individual generating units, daily load variations for the utility with emphasis on limited penetration, features of wind at prospective installation sites, makes of wind energy conversion systems (WECS) available, and recovery of expenditure through revenue. Application of the model to an assessment exercise for the state of Andhra Pradesh (India) is presented as an example.