When the switch is closed, the current I2 = 100mA, the task is to find Pe1 before the switch is closed and after it's closed and compare them.
Now I know that $$\Delta P_{E_1}=P_{E_1}^{\left(2\right)}-P_{E_1}^{\left(1\right)}=E1\left(I_1^{\left(2\right)}-I_g\right)$$
I am not sure how to start the task, finding and Thevenin equivalent for the rest of the circuit in respect of the branch with the switch isn't possible as not enough information is given.. any hints, if it's hard to provide a complete solution I would like some tips/hints in the right direction, like what theorems should be applied to solve this.