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What a Wind Energy
Wind resource assessment is a very daunting task before setting up wind farm in any region. There has been few efforts made in wind resource assessment in Nepal but the reliability of these data sets is in question. The main limiting factor of these data sets was the long time step of data measurements that makes the whole outcome pretty unreliable

Wind energy is freely available source of energy. However, the main issue in wind is that its availability mainly depends on the metrological conditions. The power output from wind farms is determined by the prevailing wind speed and direction and cannot be adjusted as conveniently as the power production from the conventional power plants.  Wind energy forecast that is how much wind power can be expected at which point of time in the next few hours and days is one of the major prerequisite for successful operation of wind farms. It helps to identify the variations in the electricity production of wind farms in advance and reduce the degree of uncertainty attributed to wind energy supply. Moreover, it further helps to schedule the wind farm operation. For instance, when the wind is in between cut in and cut out speed the wind farm can be operated, when the wind is beyond the cut out speed it would be better to shut down the plant for wind turbine and tower safety. Modern wind turbines have automatic shutdown feature if wind speed increases beyond cut out speed, but when modern wind turbines are not in use then operation schedule based on accurate metrological data might help for protecting turbines fatal like at Kagbani of Mustang, Nepal in late 80s.

Wind resource assessment is a very daunting task before setting up wind farm in any region. There has been few efforts made in wind resource assessment in Nepal but the reliability of these data sets is in question. The main limiting factor of these data sets was the long time step of data measurements that makes the whole outcome pretty unreliable. At least, one to two years wind resource data measured in a close time steps are necessary for proper analysis before wind farm installation, nevertheless, for large scale wind farm five to ten years wind resource data are considered into analysis. It is therefore, harvesting wind energy does not mean just installation of wind turbines without wind resource assessment, which is one of the major causes of the failure of wind turbine especially in developing countries. The insufficient understanding of the importance of wind resource assessment sometime cause layman advocacy in wind energy that may not yield good outcomes.

Another important issue is to level off the electricity production.  For instance, if we are to install wind farm around Kathmandu valley and aims at supplying electricity to the valley or to the national grid, how we plan to level off electricity fluctuation. Since we are unable to predict when and how much electricity will be produces by wind farms unless we have very good, reliable wind resource assessment. It is very difficult to level off grid supply for uninterrupted power supply.

Usually, in developing countries wind energy can be a suitable option for off grid electricity supply; however, Hybrid system which might include wind turbine and biodiesel generator and/or solar PV system could be an appropriate solution for most off grid supply. It is good move that several meteo masts are and are being installed in the country and hopefully their measurement would meet basic scientific standard to ensure the reasonable prediction of wind energy potential in different places of the country. In addition, it would be a good move to the government to meticulously review their implementing agencies past, present and future plans and adopted policies to ensure successful implementation of the renewable energy targets and sustainability of the implemented projects.

 By: Sunil Prasad Lohani

(You can reach the author at lohanisunil@gmail.com)

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