During the 1980's several detailed studies of the wind energy climate of Thailand were made by the Division of Energy Technology, Asian Institute of Technology, and the Meteorological Department, Ministry of Communications. Abstracts of some important publications reporting the results of this work are given below. Copies of publications by the Asian Institute of Technology may be obtained from the Regional Energy Resources Information Center.
R. H. B. Exell, S. Thavapalachandran and P. Mukhia. AIT Research Report No. 134, (1981).
Hourly wind data from Chiang Mai, Ubon, Bangkok and Hatyai during the year 1974 have been used to determine wind speed distributions at these stations in four three-month seasons of the year. Calm conditions occur from 23% to 71% of the time. In the non-calm periods the wind speeds have Weibull distributions with constant shape parameters ranging from 1.2 at Ubon to 2.0 at Hatyai, and mean wind speeds from 1m/s to over 4m/s, varying with location and season. The diurnal variations in mean wind speed and in the frequency of calm have also been studied in each season at Ubon, Bangkok and Hadyai.
The seasonal and geographic variations of wind over Thailand have been determined from monthly mean wind speeds and directions at 44 stations in the period 1951-1975. Mean wind speeds vary only slightly with season. They are generally less than 2m/s in the north of Thailand but exceed 4m/s at some stations near the sea coast. The prevailing wind directions are controlled by the south-westerly monsoon in summer and autumn, and by the easterly trade wind in winter and spring. The maximum wind velocities reported during the 25-year period are in the range 20-40m/s, depending on location.
R. H. B. Exell. Solar Energy, Vol. 35, pp. 3-13, (1985).
Routine wind data from meteorological stations have been used to determine seasonal wind speed distributions and mean power densities at the surface over Thailand. Analyses of hourly wind speeds at two stations show that Weibull distributions fit the data well, provided that observations of calm are excluded. The diurnal variation of wind at these stations has also been found. Estimates of mean power densities of surface winds over the whole country are typically in the range 10-20W/m2. Upper level climatic charts indicate that mean free-stream wind power densities above the surface boundary layer are typically in the range 100-600W/m2. Similar power densities would be accessible to wind machines on high ground in many places, depending on mountain topography and machine siting.
Chumnong Sorapipatana. Thesis No. ET-84-4, Asian Institute of Technology, (1984).
Upper wind data from the Meteorological Department for eleven stations in Thailand were used to assess the availability of wind energy above the surface boundary layer to a height of 2000m. The diurnal, seasonal and geographical variations of these upper winds have been found. The Weibull distribution was found to fit most of the data well, the occurrence of calms in the upper winds being negligible. An overall mean value for the shape parameter of 1.9 is recommended for heights 500m to 2000m, regardless of season and location. The values of the scale factor at 500m lie mostly between 4.78m/s and 5.38m/s. The effects of surface roughness and diurnal ground heating normally remain below 500m, except in the southwest monsoon (May-July) when the diurnal effect extends up to 2000m. Variations in upper wind direction are dominated by the seasonal monsoon circulation. Mean power densities at 500m in the south of Thailand are typically in the range 200-360W/m2; these power densities are comparable with those of the most promising areas for surface wind energy in Europe.
R. H. B. Exell, Chumnong Sorapipatana and Dusadee Sukawat. Solar Energy, Vol. 42, No. 6, pp. 509-513, (1989).
Studies have been made to assess the extent to which winds at height 600m can indicate wind energy potential at favorable sites in Thailand. The results suggest that winds at height 500m over the coast are close to those near the sea surface offshore for much of the day, and that upper winds from 500m to 2000m can give good estimates of winds as low as 150m both inland and near the coast.
By R. H. B. Exell, 1998. King Mongkut's University of Technology Thonburi.