The wind energy capacity addition in the State during the current financial year, which will end on Monday, is likely to be less than what it was in the previous years. Though 237 MW has been added this year, a senior official of the Tamil Nadu Electricity Board hopes the figure will cross the 300-MW-mark eventually, as the Board has given approval for installation of more windmills. The unseasonal rain earlier this month in the southern districts, especially in Tirunelveli and Kanyakumari, affected their commissioning. Another reason is that most of the high potential and commercially remunerative areas have been exhausted. T. Kanagasabai, former additional chief engineer of the Board who dealt with non-conventional energy sources for 15 years, says Muppandal and the Aranvoimozhi Pass have reached saturation. The replacement of old windmills with new ones will lead to higher production, as wind energy technology has improved over the years: taller towers and higher-capacity equipment are now available, he says. However, the idea of replacing the old mills may be workable only in clusters of windmills put up by a company or a group of companies. Those who have established one or two windmills may not find it profitable to go in for the new ones. It is not mere saturation but there are other problems that have led to the present scenario, says a spokesperson of the wind energy industry. Classification of wind energy generators as captive generating plants (restricting energy wheeling to sister concerns of wind project promoters), the requirement of more agreements and the introduction of several charges have created uncertainty. The official says the Board is only following the norms laid down by the Electricity Regulatory Commission after an elaborate process.