ظرفيت سنجي احداث نيروگاه بادي با استفاده از روش تحليل سلسله مراتبي فازي (FAHP) در استان خوزستان

Potential Feasibility of Wind Power Plants Using Fuzzy Analysis Hierarchical Process (Fahp) in Khuzestan Province

در اين تحقيق با استفاده از تحليل سلسله مراتبي فازي (FAHP)، مكان­هاي مناسب براي احداث نيروگاه بادي در استان خوزستان شناسايي شدند. معيارهاي اصلي مورد استفاده براي اين­ منظور به ­ترتيب اولويت شامل: معيارهاي فني، زيست­ محيطي و اقتصادي مي­ باشند كه هركدام از اين معيارها داراي مجموعه زيرمعيارهايي مي ­باشند. مجموعه زيرمعيارها (به ­ترتيب اولويت) شامل: چگالي قدرت باد، شيب و توپوگرافي زمين، ارتفاع زمين، فاصله از گسل (زيرمعيارهاي معيار فني)، نوع كاربري زمين، فاصله از مناطق حفاظت شده، فاصله از رودخانه، جنس خاك (زيرمعيارهاي معيار زيست ­محيطي)، فاصله از شبكه انتقال نيرو، فاصله از راه­ هاي ارتباطي، فاصله از مناطق شهري، فاصله از مناطق روستايي (زيرمعيارهاي معيار اقتصادي) مي­ باشند. تحليل سلسله مراتبي فازي انجام شده در اين تحقيق با توجه به اولويت ­بندي معيارها و زيرمعيارها انجام شد. در اين تحقيق با استفاده از اطلاعات سرعت روزانه باد، بيش­ ترين فراواني سرعت باد و سپس چگالي قدرت باد محاسبه شد. ميانگين تعداد سال ­هاي مورد استفاده جهت محاسبه بيش ­ترين فراواني سرعت باد، حدود 20 سال مي­ باشد. نتايج اين قسمت نشان داد كه، بيش­ترين فراواني سرعت باد و چگالي قدرت باد به ترتيب 7-3 (m/s) و ۲۰۹/۹۵-۱۵/۲۰۴ (wm2) است. پس از جمع­ آوري نقشه­ هاي زيرمعيارها، نقشه­ ها در محيط سامانه اطلاعات جغرافيايي (GIS) آماده و سپس با استفاده از نتايج تحليل سلسله مراتبي فازي و به ­كمك توابع موجود در سامانه اطلاعات جغرافيايي، پردازش، استانداردسازي، فازي­ سازي و در انتها پس از روي­ هم ­گذاري نقشه­ هاي ايجاد شده در مراحل قبلي، نقشه مناطق مناسب احداث نيروگاه بادي در استان خوزستان به ­دست آمد. نتايج نشان داد كه نوارهايي ازمناطق جنوب ­غرب، جنوب و بخش­ هايي از مركز استان براي احداث نيروگاه بادي بهترين گزينه­ ها هستند.

Global warming and annual increase of energy demand are two main reasons for tendency to wind energy as a clean energy. Although environment pollution due to consumption of the fossil fuels and restriction of fossil·fuels in the world are two main factors for using of wind power energy, one of the main problem about wind power is dependency on fluctuations of wind. Even though fossil fuels are still abundant and cheap due to the risk of global warming many discoveries have gone towards alternative renewable energy sources. Mainly profitability and production energy in wind farms depends on the location of the wind farm. Choose an unsuitable location for wind energy plants follow reduce the absorption of wind energy, increase the cost of maintenance and etc. Study of the potential of wind power in Iran indicated that the average of wind speed is 6~. Also the average of wind speed in s southern part of Iran is 5~. The Threshold values for wind farm construction is different in several reference and these references expressed for wind speed for example 5-6, 7-9, 3, 4.5, 3-4, 6-7 and 6 (~). In this study the wind speed is considered s as 3 ~ for wind turbine installation. In this study we used the Fuzzy Analysis s Hierarchical Process (FAHP) for site selection of wind turbine installation in Khuzestan Province. Main part in Analysis Hierarchical Process (AHP) is scoring criteria and subcriteria. In this field, the Fuzzy Logic is a useful technique taking into account a range (not an exact value) for each criterion. Latitude and longitude of Khuzestan Province is 50° 39'- 47"42' and 32°58' -29°58' respectively. Material and Methods Data used in this study include wind speed (daily wind speed) and the maps of criteria. By using calculation of the frequency of daily wind speed, the frequency of annual wind speed and then maximum frequency of wind speed for each station is calculate. The average number of years used for this part is about 20 years. Results shown that the maximum frequency of wind speed and Wind Power Density is 3-7 m s and 15.204-209.95 ( wJ respectively. This study considered 3 main criteria for wind m power site selection and every criteria was divided into the sub-criteria. The main criteria include (respect to priority): Technical criteria, Environmental criteria and Economic criteria. the sub-criteria include (respect to priority): Wind Power Density, Slope, Elevation from Sea Level, Distance from Fault (the Technical sub-criteria), Land-Use, Distance from Protected Area, Distance from River, Soil Type (the Environmental sub-criteria), Distance from Power Transmission Lines, Distance from Roads, Distance from Urban and Rural (Economic sub-criteria). In this study the roads, railway and local ways (rural ways) was merged together and these ways consider as a communication ways. For after that total layers was transformed to the raster layer then performed the standardized to these layer and finally these layers have been fuzzified. Site Selection Criteria - Land Elevation The land elevation is effective with two ways: first that at higher elevations the equipment transport becomes more difficult to build power plant and second that the height is affective in wind speed and wind speed increases with height. -Slope and Topography To achieve effective power plant, the location of turbines should not be embedded to the natural or artificial barriers. As well as higher slopes will be difficult for operation installation of plant power. Unsuitable areas including hills with slopes greater than 15 degrees. -Land Use Ideal areas include vegetation such as shrubs short, plains, grassland, bush, steppe, agricultural and infertile land. The unsuitable are wetland, high vegetation cover, high slope mountain, dunes, gravel, ice, rocks, valleys and developed areas. Distance from Protected Area Wind farm due to added a technological factor to the landscape have a negative effects on the property of their inherent nature. - Distance from River The possibility of flooding and washing areas near rivers is high and ultimately these areas will be increase the collapse of the wind turbine towers. Distance from Communication Ways Less distance of power plants from the road makes easier service to build power plant. -Distance from Urban and Rural Noise and vibration power plants turbines may cause harm to the resident's residential area adjacent to the power plants. Generally the wind turbines are not installed in urban and rural areas because the building will be barren to wind blow and also in these areas the land prices are usually high. Distance from Faulln the general case, any of structures should not be installed on fault because the movement of earth's crust is so high in these areas. -Soil Type Soils that have a higher sand can be better support structures compare with mud (silt) and clay. As well as soils with a higher organic matter content have been the lowest proportion to installing the large structures. - Distance from Power Transmission Lines The location of wind turbines depend on the structure and processes to connect in network connection. - Wind Power Density A quantitative amount of wind energy available at any points called wind power density that is most important criteria for selection the suitable sites of wind power plant. Usually the minimum wind speed to setting up the large turbines is 3-4 ~that s is depend on the type of turbine design. The electricity generation will be automatically blocked If the wind speed is greater than a specific amount so that if wind speed is 5 ~the electricity generation will be begin and generation is highest in 16 m and finally generation will be block in 25 ~to prevent damage of wind turbine components. Discussion and Conclusion According to the final map it was found that the favorable areas of wind power plant mainly located in low height areas. These areas located in Zagros Mountain to boundary of province or Persian Gulf coast. Mainly the weak or very weak regions located in the mountainous regions of East and Northeast province that main reason is fault and mountainous nature of these areas. Intermediate areas mainly located in the form of stripes between good and week areas or in Persian Gulf coast and indicate that in terms of single or many criteria are not appropriate. Good areas were identified on West, Southwest and part of Center province that reasons of them is more appropriate affecting criteria in the construction of wind farm as well as existence of strong winds in these parts. In fact more winds in Khuzestan province are blow from South, West and Southwest. So winds blow is stronger and more permanent in the Western and Southwestern parts of province. Conclusion Final point is that one of the locations for the construction of wind farms is beaches. But in Khuzestan province the occurrence of tide have caused tidal zone is very large due to lack of enough slope and so the establishment of required equipment and the possibility of establishing wind farms plants in these areas is reduced.