Answer
$55MW$
Work Step by Step
Without transformers, the power generated will be the sum of the power lost in the wires and the power used by the mall. $P=I^2R+P_M$. Using $I=\frac{P_M}{V_M}=\frac{2.0\times10^6W}{120V}=16667A$, $P=(16667A)^22(0.100\Omega)+2.0\times10^6W=5.7556\times10^7W$
With transformers, $P_M=0.99P_w=0.99I_wV_w$
$I_w=\frac{P_M}{0.99V_w}=\frac{2.0\times10^6W}{(0.99)(1200V)}=1683.5A$
$P_{lost}=I_w^2R_w=(1683.5A)^2(0.200\Omega)=5.6684\times10^5W$
$P_w+P_{lost}=0.99P_G$
$P_G=2.6132\times10^6W$
Power saved is $5.7556\times10^7W-2.6132\times10^6W=55MW$