The Advantage of Height
As we know that the surface area of the earth is limited which puts constraint on the land area utilized for a wind farm, but there is no such restriction in the vertical context. I mean to say that if a wind power machine is made higher it will occupy the same surface area on the earth, but will generate more power for the reasons given below
Dependence of Power on Wind Velocity
The power generated in a wind turbine is directly proportional to
- The square of diameter of the turbine
- The cube of the wind velocity
Mathematically this relation can be written as
Power ~ D2 * V3
So you can see that diameter is something which we can manipulate during the manufacturing process. Of course this does not mean to say that it can be extended limitlessly but still it gives lot of flexibility to the designer but the wind velocity is a natural factor which depends on the geographical location on the planet. Yet for a given location, wind velocity generally increases with height. The graph in figure 1 shows amongst other things, the variation between height from ground level and wind velocity. Since power is a function of velocity, for a given diameter power increases with velocity in a cubic fashion as described in the equation above.
All this has been very beautifully depicted in the pictorial format in figure 1 and you just need to take a close look at it. Since the height of a WARP unit is typically 5 - 6 times of a conventional turbine, you can imagine the difference in generated power by utilizing the same area on land but little more height in space.
You can also notice in the graph that the wind turbine shown is around 500 KW capacity while the WARP unit is nearly 10 times in capacity i.e. 5000 KW or 5 MW. The reason is that the WARP consists of a number of modules each having a generation unit one on top of the other, thereby increasing the overall capacity. The left hand side of the graph shows the relative comparison between power generated by a conventional turbine vis-à-vis a WARP unit.
Hence we see that apart from saving land space, WARP units offer better power generation capacity by utilizing the advantage of increased wind power at the higher altitude. In the next article of the series, we will continue our study of the advantages of WARP over conventional wind turbines.