Question $1(15$ marks$)$

a$-$ Describe two types of wind turbine towers and their main advantages. Why does tower height matter in wind turbine performance?

b $-$Why is aerodynamic braking typically used during normal operations rather than in emergencies?

c$-$The wind speed at two different sites can be represented using the Rayleigh statistics with scale parameters equal to $8$ and $4,$ respectively. Assume the air density at both sites to be $1\mathrm{.}225k\frac{g}{m^3}.$

i$)$ Find the average wind speed at each site.

ii$)$ Find the energy in the wind per unit area over a period of $1$ year for both sites.

iii$)$ If you were to install a wind turbine at one of the sites, which site would you choose