Suitable location

Wind turbines need a minimum wind speed of 3.5 metres per second to generate electricity. But a wind speed of more than 25 metres per second could damage the windmill.

Before deciding the site where windmills should be ideally located, the wind pattern over a 15-year period is studied.

The Indian belt is considered a low to medium wind regime region, where the average usable wind speed for energy generation is about 6 metres per second. In Europe and the US, which are considered high wind regime regions, most wind farms have been put up where the average wind velocity per annum is 14 to 15 metres per second, and the energy generated there is three to four times that in India.

Since different wind speeds prevail in different parts f the country, only some parts of the country are found suitable for wind energy projects.

The union ministry of non-conventional energy sources has identified around 200 such sites in the country, the most favourable and the most exploited of which is in Tamil Nadu. Next comes Gujarat followed by Maharashtra, Andhra Pradesh, Karnataka and the North Eastern states.

In Maharashtra, 21 sites have been identified as suitable for harnessing wind energy. A sizeable number of windmills are located on the hills around Satara and Sangli, in Wankuswade, Chalkewadi, Thoseghar, Gude and Panchgani, where the average wind speeds are in the region of 8 metres per sec. The low hills across the area with flat plateau-like tops along with extensive shallow valleys make these ideal spots for the winds to gently gather up speed and culminate in powerful gusts across the hilltops. Another site fast catching up, as an attractive wind energy site in Maharashtra is Supa, near Ahmednagar.

There has to be enough land spread at a particular site to put up windmills. Each wind mill tower needs a footprint of 14 feet by 14 feet. The land around the windmills can be used for cultivation. On an average 1 MW of power can be generated in 15-25 acres of land.

Of the 20 odd sites found to be suitable in terms of wind speeds in Maharashtra, only three or four are well developed in terms of infrastructure, which is where investments have come in. Sindhudurg, for example, despite being a good wind speed site, has not attracted investment for lack of infrastructure.