At home we press a button and want the fans to rotate. What goes behind generating that power is something we seldom care. Had an opportunity to spend a few moments with mighty windmills on a hill somewhere in Shimoga district. So far I'd seen them only from a distance and this was an opportunity to see them from close quarters.
They look tiny from a distance, but once you go close, the sheer size of these components amazes us. An assembly of 3 blades is mounted on top of a huge pillar.
The pillar is about 77 meters high and is erected on a strong concrete foundation which is said to be made up of 1000+ bags of cement and corresponding quantities of stones and sand. Precision engineering is required to erect these towers, as even 1 degree of deviation from upright position can mean that tower will soon incline and eventually collapse.The tower has a door and internal staircase for maintenance staff to reach the top of the tower where rotor blades are mounted. The estimated cost of each windmill tower is about a crore plus and these are built and maintained by Suzlon.
The blade starts rotating once wind speed is more than 4 meters per second and runs optimally till a speed of 20 meters per second, beyond which power generation stops. The blades and tower are rated to survive windspeeds of up to 50 meters per second. If the wind blows even faster, there is a risk that these structures may not withstand the onslaught.
Periodical maintenance is required to lubricate the gears etc, so there is some negligible operational cost involved, else it would ensure unlimited supply of green energy.
|Supplying to the grid|