A GIS based assessment of potential for windfarms in India

The Wind Energy Potential for India has been assessed, assuming as if the whole of the country (apart from the urban and the Himalayan areas) is covered with windfarms, by an innovative approach using GIS platform, wind speed measurements under government’s program and the NCEP/NCAR Reanalysis data.11The NCEP/NCAR Reanalysis Project is a joint project between the National Centres for Environmental Prediction (NCEP, formerly "NMC") and the National Centre for Atmospheric Research (NCAR). The goal of this joint effort is to produce new atmospheric analysis using historical data and as well to produce analysis of the current atmospheric state (Climate Data Assimilation System, CDAS). It contains the information of climate variables with different time setups. For the analysis, data has been collected from different data sources like, COADS surface marine data, the comprehensive Ocean-Atmospheric Data set includes ships, fixed buoys, drifting buoys, pack-ice buoys, near- surface data from ocean station reports. Still some work is in progress to collect all the surface marine data for 1947-79. Aircraft data, Surface land synoptic data, special sensing microwave imager data, surface wind speeds, satellite cloud drift winds, and satellite sounder data. The methodology involves setting up a grid of 1 sqkm resolution over areas other than urban settlements and Himalayan regions, computation of wind speeds at boundary layer level through vertical extrapolation of known or measured mean annual wind speed and interpolation of the extrapolated wind speeds to arrive at a mean annual wind field at boundary layer level and then computation of wind speed at the hub-height of the wind turbine. Power output from a standard wind turbine is computed and only areas showing a Plant Load Factor (PLF) higher than 15% are considered in the potential assessment. The results of this exercise indicate the potential for windfarms in India to be significantly higher than what was assumed earlier. The analysis and its revalidation using data measured at varying heights in different parts of the country establishe this approach as useful and perhaps a powerful tool to undertake wind resource potential assessments. This analysis and the results are discussed in the backdrop of the general energy scenario in India and earlier assessments of wind potential in the country.