: A very large horizontal wind turbine is mounted with its hub at $135$ m and has a rotor diameter of $126$ m$.$ The turbine operates in an area with an average wind speed of $12$ m$/$s at $135$ m altitude and air density of $1\mathrm{.}18$ kg$/$m$3$ at $70$ F$.$ The turbine power coefficient is $0\mathrm{.}46.$ The generator is directly coupled to the turbine without a gearbox. Assume the following efficiencies: Turbine blade efficiency $=94\mathrm{.}6\%,$ generator efficiency $=96\%.$ Determine the electrical power output and annual energy generation.