Wind Resource Assessment over Kutubdia Island, Bangladesh

Kutubdia, an Island close to the eastern coast of Bangladesh, has an area of 67.69 sq-km and is located within the latitude of 21.70˚ to 21.94˚ N and longitude of 91.84˚ to 91.90˚ E and the population is around 0.1 million. Several rice husking mills, shrimp farms, salt processing plants, primary and higher secondary schools and a health complex are situated in this Island. Bangladesh Meteorological Department (BMD) finds the annual average wind speed over the last ten years (1991 - 2000) to be 1.68 m/s at a height of 13m at their location (91.85˚ E, 21.82˚ N). But Bangladesh Centre for Advanced Studies (BCAS) finds that their measurements at a different site (91.84˚ E, 21.86˚ N) over a year lead to an annual value of 4.15 m/s at a height of 25m [WEST, 1998] which appears to be promising for wind electricity generation. One expects that at 50m height higher speeds may occur. The present work attempts to assess the wind resource at 50m height over the Island and predict the good locations for wind generators. For this purpose "Wind Atlas Analysis and Application Program (WAsP)", [Troen I, 1989] developed at RISO National Laboratory, Denmark has been employed which uses time series of wind data along with information on surface characteristics of the location, obstacles due to buildings and trees close to the met station and the orography. WAsP has been used to develop the frequency response of the wind speed, wind rose, monthly and annual Weibull parameters (shape factor, K and scale factor, A) and the Wind Atlas at 50m height from the BMD data of Kutubdia. An attempt has been taken to predict the wind speeds for the BCAS location at 25m height from the wind atlas developed and to compare them with experimental data (Table 3). A close agreement found between them validates the technique. The Monthly and Annual Wind Atlas over Kutubdia for four roughness conditions and for five heights have been developed and a pre-feasibility analysis has been done to obtain the wind speed and power density for the four selected locations. Fig. 1 shows the position of the monitoring stations in the map of Kutubdia Island and the location of Kutubdia Island in Bangladesh. The distance between the two monitoring stations is around 3 Km.