Wind is moving in a direction normal to the plane of a horizontal axis turbine, which has a swept radius of $8$ m$.$ The upstream wind speed is $14$ m$.$s$-1$ and downstream wind speed is $12$ m$.$s$-1.$ Assuming a constant air density of $1\mathrm{.}293$ kg$.$m$-3,$ calculate the useful power output from the wind turbine generator, assuming an electromechanical coupling efficiency of $90\%,$ and no other losses. Give your answer in kilowatts $($kW$),$ correct to $1$ decimal place.