Decentralized/stand-alone hybrid Wind–Diesel power systems to meet residential loads of hot coastal regions

In view of rising costs, pollution and fears of exhaustion of oil and coal, governments around the world are encouraging to seek energy from renewable/sustainable energy sources such as wind. The utilization of energy from wind (since the oil embargo of the 1970s) is being widely disseminated for displacement of fossil fuel produced energy and to reduce atmospheric degradation. A system that consists of a wind turbine and Diesel genset is called a Wind–Diesel power system.The literature indicates that the commercial/residential buildings in Saudi Arabia consume an estimated 10–40% of the total electric energy generated. In the present study, the hourly mean wind-speed data of the period 1986–1997 recorded at the solar radiation and meteorological station, Dhahran (26°32′N, 50°13′E in the Eastern Coastal Region of Saudi Arabia), has been analyzed to investigate the potential of utilizing hybrid (Wind–Diesel) energy conversion systems to meet the load requirements of a hundred typical two bedroom residential buildings (with annual electrical energy demand of 3512 MWh). The long term monthly average wind speeds for Dhahran range from 4.2 to 6.4 m/s. The hybrid systems considered in the present case study consist of different combinations/clusters of 150 kW commercial wind machines supplemented with battery storage and Diesel back-up. The deficit energy generated by the Diesel generator (for different battery capacities) and the number of operational hours of the Diesel system to meet a specific annual electrical energy demand of 3512 MWh have also been presented. The evaluation of the hybrid system shows that with seven 150 kW wind energy conversion system (WECS) and one day of battery storage, the Diesel back-up system has to provide 21.6% of the load demand. Furthermore, with three days of battery storage, the Diesel back-up system has to provide 17.5% of the load demand. However, in the absence of battery storage, about 37% of the load needs to be provided by the Diesel system. The study also places emphasis on the monthly average daily energy generation from different sizes (150 kW, 250 kW, 600 kW) of wind machines to identify the optimum wind machine size from the energy production point of view. It has been noted that for a given 6 MW wind farm size (for 50 m hub height), a cluster of forty 150 kW wind machines yields about 48% more energy as compared to a cluster of ten 600 kW wind machines.     

Wind energy as a potential generation source at Ras Benas,Egypt

Analysis of the wind characteristics in Ras Benas city located on the east coast of Red Sea in Egypt using measured data (wind, pressure and temperature) and Weibull function were made.Statistical analysis model to evaluate the wind energy potential was introduced. According to the power calculations done for the site, the annual mean wind density is 315 kW/m² at a height of 70 m above ground level. This station has a huge wind energy potential for electricity generation, especially during spring and summer seasons, comparing with some European countries.In addition, the monthly wind turbine efficiency parameter (η_monthly) has been calculated by using a commercial wind turbine 1 MW with 70 m hub height to help designers and users in evaluating the potentialities and choosing the suitable wind turbine for the considered site. The use of wind turbine with capacity greater than 1000 kW at this station was recommended.Ras Benas station was selected to install 30 MW-wind farm consists of 20 commercial wind turbines (Nordex S 77) with hub heights and Rotor diameter were 100 and 77 m, respectively. This site has annual wind speed more than 9.8 m/s at 100 m height and enough area to locate these turbines.The estimated energy production using WASP Program of these wind farm was 130 GWh/year. Furthermore, the production costs was found 1.3€ cent/kWh, which is a competition price at the wind energy world market.     

Design optimization and site matching of direct-drive permanent magnet wind power generator systems

This paper investigates the possible site matching of the direct-drive wind turbine concepts based on the electromagnetic design optimization of permanent magnet (PM) generator systems. Firstly, the analytical models of a three-phase radial-flux PM generator with a back-to-back power converter are presented. The optimum design models of direct-drive PM wind generation system are developed with an improved genetic algorithm, and a 500-kW direct-drive PM generator for the minimal generator active material cost is compared to demonstrate the effectiveness of the design optimization. Forty-five PM generator systems, the combinations of five rated rotor speeds in the range of 10–30 rpm and nine power ratings from 100 kW to 10 MW, are optimally designed, respectively. The optimum results are compared graphically in terms of the generator design indexes. Next, according to the design principle of the maximum wind energy capture, the rotor diameter and the rated wind speed of a direct-drive wind turbine with the optimum PM generator are determined. The annual energy output (AEO) is also presented using the Weibull density function. Finally, the maximum AEO per cost (AEOPC) of the optimized wind generator systems is evaluated at eight potential sites with annual mean wind speeds in the range of 3–10 m/s, respectively. These results have shown the suitable designs for the optimum site matching of the investigated PM generator systems.     

Assessment of wind power potential for turbine installation in coastal areas of Turkey

This paper analyses the potential and the feasibility basis for the wind energy resources in some locations of coastal regions of Turkey. The dominant wind directions, the mean values, wind speeds, wind potential and the frequency distributions were determined. The results showed that Bal?kesir and Çanakkale among annual averages show higher value of mean wind speed. The mean annual value of Weibull shape parameter k is between 1.54 and 1.86 while the annual value of scale parameter c is between 2.52 m/s and 8.34 m/s. A technical assessment has been made of electricity generation from four wind turbines having capacity of 600 kW, 1500 kW, 2000 kW and 2500 kW. The yearly energy output and capacity factor for the four different turbines were calculated.     

Economic feasibility of large community feed-in tariff-eligible wind energy production in Nova Scotia

Nova Scotia, Canada's community feed-in tariff (COMFIT) scheme is the world's first feed-in tariff program specifically targeting locally-based renewable energy projects. This study investigated selected turbine capacities to optimize electricity production, based on actual wind profiles for three sites in Nova Scotia, Canada (i.e., Sydney, Caribou Point, and Greenwood). The turbine capacities evaluated are also eligible under the current COMFIT-large scheme in Nova Scotia, including 100 kW, 900 kW and 2.0 MW turbines. A capital budgeting model was developed and then used to evaluate investment decisions on wind power production. Wind duration curves suggest that Caribou Point had the highest average wind speeds but for shorter durations. By comparison, Sydney and Greenwood had lower average wind speeds but with longer durations. Electricity production cost was lowest for the 2.0 MW turbine in Caribou Point ($0.07 per kWh), and highest for the 100 kW turbine located in Greenwood ($0.49 per kWh). The most financially viable wind power project was the 2.0 MW turbine assumed to operate at 80 m hub height in Caribou Point, with NPV=$251,586, and BCR=1.51. Wind power production for the remaining two sites was generally not financially feasible for the turbine capacities considered. The impact of promoting local economic development from wind power projects was higher in a scenario under which wind turbines were clustered at a single site with the highest wind resources than generating a similar level of electricity by distributing the wind turbines across multiple locations.     

Consequences of a carbon tax on household electricity use and cost,carbon emissions,and economics of household solar and wind

The study was conducted to determine the consequences of a carbon tax, equal to an estimated social cost of carbon of $37.2/Mg, on household electricity cost, and to determine if a carbon tax would be sufficient to incentivize households to install either a grid-tied solar or wind system. U.S. Department of Energy hourly residential profiles for five locations, 20 years of hourly weather data, prevailing electricity pricing rate schedules, and purchase prices and solar panel and wind turbine power output response functions, were used to address the objectives. Two commercially available household solar panels (4 kW, 12 kW), two wind turbines (6 kW, 12 kW), and two price rate structures (traditional meter, smart meter) were considered. Averaged across the five households, the carbon tax is expected to reduce annual consumption by 4.4% (552 kWh/year) for traditional meter households and by 4.9% (611 kWh/year) for households charged smart meter rates. The carbon tax increases electricity cost by 19% ($202/year). For a household cost of $202/year the carbon tax is expected to reduce social costs by $11. Annual carbon tax collections of $234/household are expected. Adding the carbon tax was found to be insufficient to incentivize households to install either a solar panel or wind turbine system. Installation of a 4 kW solar system would increase the annual cost by $1546 (247%) and decrease CO₂ emissions by 38% (2526 kg) valued at $94/household. The consequence of a carbon tax would depend largely on how the proceeds of the tax are used.     

Feasibility study of hydrogen production from wind power in the region of Ghardaia

A feasibility study on hydrogen production from wind power on the site of Ghardaia is carried out. This study is based on the estimation of the hydrogen rate produced by a 5 kW electrolyser fed by the electricity provided by a 10 kW wind turbine.Wind speed data were used to study the monthly variation of the wind power delivered and its variation according to the height of the wind turbine tower.The obtained results show that it is possible to improve the system output by increasing the height of the wind turbine tower. Indeed, it has been obtained 3200 Nm³ of hydrogen production for a 30 m wind turbine height and 4200 Nm³ at 60 m.In addition, it has been noticed that hydrogen production varies strongly with the months of the year. Thus, the production has reached a maximum of 395 Nm³ in May and a minimum of 187 Nm³ during November and October.     

Wind energy for rural areas of Algeria

This paper presents long-term analysis of wind speed data in terms of annual, seasonal and diurnal variations at Tindouf, which is situated on the south west region of Algeria. The wind speed data was collected over a period of 08 years between 1976 and 1984. The study showed that the long-term seasonal wind speeds were found to be relatively higher during September compared to other months. The diurnal change in long-term mean wind speed indicated that higher electricity could be produced during 09:00–18:00 h, which also coincides with higher electricity demand period. The annual wind energy production and capacity factor, obtained using wind speed frequency distribution and wind power curve of 1000 kW wind turbine and RETScreen software were found comparable with each other if unadjusted energy production values calculated by the software were used rather than the renewable energy delivered. Development of wind farm of 30 MW installed capacity at this site could result into avoidance of 23,252 tonnes/year of CO₂ equivalents GHG from entering into the local atmosphere thus creating a clean and healthy atmosphere for local inhabitants.     

Wind power utilization for water pumping using small wind turbines in Saudi Arabia: A techno-economical review

An attempt has been made, may be first time in Saudi Arabia, to utilize power of the wind for pumping the water for remotely located inhabitants not connected with national power grid. Small turbines of 1–10 kW have been chosen in conjunction with Goulds 45 J model water pumps to produce energy from wind and pump water using the produced energy at Arar, Rawdat Ben Habbas and Juaymah localities in Saudi Arabia. Wind speed measurements made at different heights using 40 m tall towers have been utilized in the present work. Higher wind speeds were noticed during summer time compared to winter time at all the locations. Both energy yield and cost of energy point of view, 2.5 kW wind turbine from Proven was found to be most suitable for wind power generation at all sites. It is shown that annual total water pumping capacity of 30,000 m³ is possible from a depth of total dynamic head of 50 m when using 2.5 kW Proven wind turbine with hub heights 15–40 m at all three sites with cost of water pumping as low as 1.28 US¢/m³.     

Dynamic behavior of a stand-alone hybrid power generation system of wind turbine,microturbine, solar array and battery storage

This paper presents dynamic behavior and simulation results in a stand-alone hybrid power generation system of wind turbine, microturbine, solar array and battery storage. The hybrid system consists of a 195 kW wind turbine, an 85 kW solar array; a 230 kW microturbine and a 2.14 kAh lead acid battery pack optimized based on economic analysis using genetic algorithm (GA). At first, a developed Lyapunov model reference adaptive feedback linearization method accompanied by an indirect space vector control is applied for extraction of maximum energy from a variable speed wind power generation system. Then, a fuzzy logic controller is designed for the mentioned purpose and its performance is compared with the proposed adaptive controller. For meeting more load demands, the solar array is integrated with the wind turbine. In addition, the microturbine and the battery storage are combined with the wind and solar power generation system as a backup to satisfy the load demand under all conditions.A supervisory controller is designed in order to manage energy between the maximum energy captured from the wind turbine/solar arrays, and consumed energies of the load, dump load, battery state of charge (SOC), and generated energy by the microturbine. Dynamic modeling and simulation are accomplished using MATLAB Simulink? 7.2.     

Investigation of wind energy potential of Muradiye in Manisa,Turkey

The purpose of this survey is about to investigate wind energy potential of Celal Bayar University Muradiye Campus. The experimental system was commissioned in November 2006 and performance monitoring tests have been conducted since then. Author also undertake a case study to investigate how varying wind speeds considered affect the electricity production of the wind turbine system and to estimate a capacity factor which is defined as the ratio of the average power output to the rated output power of the generator. The collected data are quantified and illustrated in the tables, 07th of November 2006 till 09st of December 2007 for comparison purposes. According to experimental studies between 2006 and 2007 years, yearly average wind velocity is found to be 3.21 m/s at 30 m height and capacity factor is estimated to be 14.1% for Enercon E48 (800 kW) wind turbine. According to these results, the mean wind speed does not provide economical electricity production from the wind energy.     

A compact,high efficiency contra-rotating generator suitable for wind turbines in the urban environment

This paper is concerned with the design, development and performance testing of a permanent magnet (PM) generator for wind turbine applications in urban areas. The radially interacting armature windings and magnet array are carried on direct drive, contra-rotating rotors, resulting in a high torque density and efficiency. This topology also provides improved physical and mechanical characteristics such as compactness, low starting torque, elimination of gearboxes, low maintenance, low noise and vibration, and the potential for modular construction. The design brief required a 50 kW continuous rated prototype generator, with a relative speed at the air-gap of 500 rpm. A test rig has been instrumented to give measurements of the mechanical input (torque and speed) and electrical output (voltage, current and power) of the generator, as well as temperature readings from inside the generator using a wireless telemetry device. Peak power output was found to be 48 kW at a contra-rotating speed of 500 rpm, close to the design target, with an efficiency of 94%. It is anticipated that the generator will find application in a wide range of wind turbine designs suited to the urban environment, e.g. types sited on the top of buildings, as there is growing interest in providing quiet, low cost, clean electricity at point of use.     

Technical review of wind energy potential as small-scale power generation sources in Penang Island Malaysia

This project presents an investigation and assessment of the wind energy potential in Penang Island, located about 15 km off the west (W) coast of Peninsular Malaysia. The wind data were statistically analyzed using Rayleigh distribution function. Based on the investigation, the results show that the measurement site falls under Class 1 of the International System Wind Classification. The climate in Penang Island is highly influenced by the northeast (NE) and southwest (SW) monsoon seasons. Besides that, most of the wind is the prevailing wind from the north (N) and SW directions. Meanwhile, the directions that contribute higher energy frequency are from NE and south-southwest (SSW). The mean annual wind power density (WPD) in this regime is estimated to be about 24.54 W m^?2. Furthermore, the mean annual wind energy density (WED) is also forecast to be 17.98 kWh m^?2 month^?1. The total annual WED is 216 kWh m^?2 year^?1. Thus, the results of this investigation indicate that the grid-network connected to the wind turbine-generator systems may not be a commercially viable proposal in Penang. Nevertheless, a small-scale wind turbine system is more suitable and sustainable in Penang Island.     

Wind power resource assessment for Rafha,Saudi Arabia

This paper, presents the analysis of wind speed data and available energy in Rafha area using wind machines of 600, 1000 and 1500 kW sizes from three manufacturers. The long-term annual mean values of wind speeds were found to vary between a minimum of 2.5 m/s in the year 2002 and a maximum of 4.9 m/s in 1990. The frequency distribution showed that wind remained silent for 7% of the time on an average during 24 years of data period and 35% between 0 and 3.5 m/s. Wind speed remained above 3.5 m/s for 65% of the time and only 20% of the times above 6.5 m/s. The annual wind energy production and plant capacity factors, obtained using different methods and wind machines of three sizes and from three manufacturers are also discussed and compared.     

Wind forecasts for wind power generation using the Eta model

The goal of this article is to apply the regional atmospheric numerical weather prediction Eta model and describe its performance in validation of the wind forecasts for wind power plants. Wind power generation depends on wind speed. Wind speed is converted into power through characteristic curve of a wind turbine. The forecasting of wind speed and wind power has the same principle.Two sets of Eta model forecasts are made: one with a coarse resolution of 22 km, and another with a nested grid of 3.5 km, centered on the Nasudden power plants, (18.22°E, 57.07°N; 3 m) at island Gotland, Sweden. The coarse resolution forecasts were used for the boundary conditions of the nested runs. Verification is made for the nested grid model, for summers of 1996–1999, with a total number of 19 536 pairs of forecast and observed winds. The Eta model is compared against the wind observed at the nearest surface station and against the wind turbine tower 10 m wind. As a separate effort, the Eta model wind is compared against the wind from tower observations at a number of levels (38, 54, 75 and 96 m).Four common measures of accuracy relative to observations - mean difference (bias), mean absolute difference, root mean square difference and correlation coefficient are evaluated. In addition, scatter plots of the observed and predicted pairs at 10 and 96 m are generated. Average overall results of the Eta model 10 m wind fits to tower observations are: mean difference (bias) of 0.48 m/s, mean absolute difference of 1.14 m/s, root mean square difference of 1.38 m/s, and the correlation coefficient of 0.79. Average values for the upper tower observation levels are the mean difference (bias) of 0.40 m/s; mean absolute difference of 1.46 m/s; root mean square difference of 1.84 m/s and the correlation coefficient of 0.80.     

Day-ahead wind speed forecasting using f-ARIMA models

With the integration of wind energy into electricity grids, it is becoming increasingly important to obtain accurate wind speed/power forecasts. Accurate wind speed forecasts are necessary to schedule dispatchable generation and tariffs in the day-ahead electricity market. This paper examines the use of fractional-ARIMA or f-ARIMA models to model, and forecast wind speeds on the day-ahead (24 h) and two-day-ahead (48 h) horizons. The models are applied to wind speed records obtained from four potential wind generation sites in North Dakota. The forecasted wind speeds are used in conjunction with the power curve of an operational (NEG MICON, 750 kW) turbine to obtain corresponding forecasts of wind power production. The forecast errors in wind speed/power are analyzed and compared with the persistence model. Results indicate that significant improvements in forecasting accuracy are obtained with the proposed models compared to the persistence method.     

An analysis of wind power potential in Port Said,Egypt

Measurement station with mast of 19 m has been established in a built-up area, near the seashore to study the structure of a coastal location “Port Said” on Suez Canal–Mediterranean Sea intercept in Egypt. From our analysis of the wind data, an important characteristic is revealed in that the wind speed Spring months are more than that in Winter period. This characteristic is opposite to the prevailing wind speed parameters in most European countries. This paper also gives a detailed analysis of measured frequency distributions and monthly wind speed variation with air temperature that can exploited in the best way for fast wind machines.A numerical model was introduced to calculate the monthly and annual average wind energy flux and found to be quite moderate (in excess of 92 kW/m² per year at 50 m hub height) for this area.It appears from our research that the expected energy from the wind in Port Said region – which is nearly like an island – lies in the medium range. This potential can be converted to electrical energy specially in the Spring months. However, an immediate application seems to be limited to electricity generation using medium size wind farms and water pumping.     

California offshore wind energy potential

This study combines multi-year mesoscale modeling results, validated using offshore buoys with high-resolution bathymetry to create a wind energy resource assessment for offshore California (CA). The siting of an offshore wind farm is limited by water depth, with shallow water being generally preferable economically. Acceptable depths for offshore wind farms are divided into three categories: ≤20 m depth for monopile turbine foundations, ≤50 m depth for multi-leg turbine foundations, and ≤200 m depth for deep water floating turbines. The CA coast was further divided into three logical areas for analysis: Northern, Central, and Southern CA. A mesoscale meteorological model was then used at high horizontal resolution (5 and 1.67 km) to calculate annual 80 m wind speeds (turbine hub height) for each area, based on the average of the seasonal months January, April, July, and October of 2005/2006 and the entirety of 2007 (12 months). A 5 MW offshore wind turbine was used to create a preliminary resource assessment for offshore CA. Each geographical region was then characterized by its coastal transmission access, water depth, wind turbine development potential, and average 80 m wind speed. Initial estimates show that 1.4–2.3 GW, 4.4–8.3 GW, and 52.8–64.9 GW of deliverable power could be harnessed from offshore CA using monopile, multi-leg, and floating turbine foundations, respectively. A single proposed wind farm near Cape Mendocino could deliver an average 800 MW of gross renewable power and reduce CA's current carbon emitting electricity generation 4% on an energy basis. Unlike most of California's land based wind farms which peak at night, the offshore winds near Cape Mendocino are consistently fast throughout the day and night during all four seasons.     

A review on wind energy and wind–hydrogen production in Turkey: A case study of hydrogen production via electrolysis system supplied by wind energy conversion system in Central Anatolian Turkey

Studies about investigation of hydrogen production from wind energy and hydrogen production costs for a specific region were reviewed in this study and it was shown that these studies were rare in the world, especially in Turkey. Therefore, the costs of hydrogen, hydrogen production quantities using a wind energy conversion system were considered as a case study for 5 different locations of Nigde, Kirsehir, Develi, Sinop and Pinarbasi located in the Central Anatolia in Turkey. Annual wind energy productions and costs for different wind energy conversion systems were calculated for 50 m, 80 m and 100 m hub heights. According to wind energy costs calculations, the amounts and costs of hydrogen production were computed. Furthermore, three different scenarios were taken into account to produce much hydrogen. The results showed that the hydrogen production using a wind energy conversion system with 1300 kW rated power had a range from 1665.24 kgH₂/year in Nigde at 50 m hub height to 6288.59 kgH₂/year in Pinarbasi at 100 m hub height. Consequently, Pinarbasi and Sinop have remarkable wind potential and potential of hydrogen production using a wind–electrolyzer energy system.     

Wind energy in the Gulf of Tunis,Tunisia

This paper presents a study of wind resource in the Gulf of Tunis. During 2008, an experimental measurement of wind speed and wind direction at 20 m and 30 m, were conducted using a 10-min time step. The statistic treatment of results permitted us to evaluate the most characteristics of wind energy in the studied site. An extrapolation of wind speed is, also, carried out using the deduced power law exponent. The annual production of the wind turbine Enercon E82 is estimated at a height of 100 m above ground level. The obtained results can be used to perform wind park project and confirm that the Gulf of Tunis has promising wind energy potential.