Our energy-hungry world is always on the lookout for cheaper and more sustainable sources of energy. Wind energy is one source that has not caught on as much as solar energy has, largely because wind speed and direction are uncertain. There are also challenges associated with erecting wind turbines at the best locations.
Also, storage of wind energy is not as easy as storing solar energy; it is in fact, ideal, if wind power is fed into the electricity grid when the wind is blowing.
The SeaTwirl system, whose prototype was successfully demonstrated in Sweden in August, may well change the way we look at wind energy. The SeaTwirl is essentially a flywheel in the middle of the sea. It comprises a vertical wind turbine with a hollow, doughnut-shaped ring attached to its base.
A vertical axle runs through the turbine, extending all the way into the water. The axle is connected to a generator and anchor lines hold the entire system in place.
Only the turbine and the ring are visible above the water and another advantage of this design is that much of the SeaTwirl’s weight is borne by the water on which it sits. This reduces the need for light-weight, but expensive materials to be used in construction.
The turbine spins irrespective of the direction of the wind.
Along with the turbine, the attached axle also rotates and electricity is generated where the rotating axle meets the non-rotating generator. Cables connecting the generator to a sub-station on the shore carry electrical power that is then fed into the grid.
Designers of the SeaTwirl claim that on average, a commercial-scale unit can generate 39,000 MW of power annually, and can store 25,000 KwH of power.