The initiative, which would involve measuring wind speed from towers as tall as 100 metre, comes more than a decade after the centre embarked on a similar exercise to validate the potential at 50-metre hub heights. Wind speeds are greater at higher tower heights, though the density is lower.
Recent revised estimates by the Chennai-based C-WET, a research and development institution under the ministry for new and renewable energy, indicate a potential for 102 gigawatt (GW) at hub heights of 80 metre against the previous estimates of 49.2 GW at 50-metre towers. That needs to be validated and the government has already taken up a comprehensive plan to do so by simultaneous measurement at 75 locations, said S Gomathinayagam, executive director, C-WET.
The project would likely commence in the next two months after tenders are finalised and the validation is expected to take at least 2-3 years. We should have one-year data without any interruption, he said. Currently, most of the 1-MW class of turbines in operation in the country have hub heights of 70-80 metre, he added.
While the wind energy estimates so far have assumed a 2% land availability, the reassessment project also aims at using Geographic Information System (GIS) techniques to assess the land availability in seven states and estimate technical potential. According to C-WET, the earlier assumption had been based on the results of micro survey studies done for a few stations in the country because land assessment was not a part of the wind atlas preparation.
Last month, researchers at the California-based Lawrence Berkeley National Laboratory (LBNL) reported that a new assessment of wind energy in India found that the potential for on-shore wind energy deployment was up to 30 times greater than the official government estimate of 102 GW. According to the researchers, the primary reason for the higher estimates was because they used publicly available GIS data on topography and land use, which indicated a significantly higher availability of land for wind power development, against C-WET's assumption of 2% of windy land being available for development.
The LBNL study was encouraged by recent re-assessments of wind potential in the US and China that had found substantial increases over previous estimates.
"They have based it on some thematic GIS maps, which is a demonstration of the application of some modern tools to wind energy. But they need to be validated by actual measurement," said Gomathinayagam.
India added around 3,000 MW of wind energy capacity in calender year 2011, the highest rate of capacity addition achieved so far in a single year. The country's total installed capacity stood at 16,078 MW as of December 2011. The private sector investment into setting up installations amounted to R38,093 crore over the last three years, during which wind power capacity of 6,926 MW has been installed in the country, according to the ministry for new and renewable energy.