The total windmill capacity in India is now 9,000MW (3,594 MW in 2005) and around Rs30,000 crore has been invested in various windmill projects across the country.
Every reputed industrial group—even those who have nothing to do with the power sector— wants a piece of the windmill pie. According to the Centre for Wind Energy Technology (C-WET), India has a wind farm potential of 48,000 MW. This will require an investment of Rs3,00,000 crore.
But here’s the catch. The investment is nothing other than a depreciation machine with hardly any productivity. If the total potential of 48,000MW is realised, this will generate 48-75 billion KWh of electricity whereas if this amount is spent on thermal plants worth 75,000 MW, they will generate 525 billion KWh of electricity.
For instance, Tata Power put up its 80 MW wind power project in a windy area in 2008-09; it produced 1.6 million KWh for each MW of the windmill project. At its Trombay power house—where Tata Power has its 1,580MW thermal power project—it produced 9,845 million units accounting for 6.2 million KWh per MW. However, Tata’s windmill project was set up in a windy area. The situation is worse in other places where wind blades hardly move and generate negligible power.
A comparison of thermal power plants and windmill projects throws up some surprising figures. Thermal plants generate around 6-7 million KWh per MW of capacity despite their low efficiency of 36% as power is generated from coal to steam to turbine generator. Against this, windmills have no loss of efficiency in the process of converting wind to electricity as wind blades are directly attached with the rotor and generator. Despite this they get only one million KWh of electricity per MW.
Only plus point with windmills is that they have no raw material cost. But looking at the huge cost which is 1.5 times higher than thermal plant, why is the government promoting wind mills?
One answer may be thanks to depreciation benefits. The entire cost of a windmill plant can be depreciated in the first year of operation if it is used for more than 180 days other wise 80% cost can be depreciated even if it is used for one day under section 32 of the Income-Tax Act.