A penstock of $1 \: m$ diameter and $5 \: km$ length is used to supply water from a reservoir to an impulse turbine. A nozzle of $15 \: cm$ diameter is fixed at the end of penstock. The elevation difference between the turbine and water level in the reservoir is $500 \: m$. Consider the head loss due to friction at $5\%$ of the velocity head available at the jet. Assume unit weight of water $=10 \: kN/m^3$ and acceleration due to gravity $(g) = 10 \: m/s^2$. If the overall efficiency is $80\%$, power generated (expressed in $kW$ and rounded to nearest integer) is _________