If the voltage used to operate a circuit is increased, then the current flowing at every point in the circuit will increase, and the power radiated by the components in the circuit will also increase.
If you increase the voltage TOO much, then you may need to start cooling the circuit to prevent fire, or to prevent components from failing.
The relationship between power current and voltage is given by the following equation;
P=IV
P = power
V = voltage
I = current
When the voltage (V is increased and the current (I) is maintained, then the power will definitely increase.
Increasing the voltage also increases the distance that the power can be transmitted with little attenuation or loss. This is why voltage is usually stepped up (which will reduce current) significantly at power stations before it's transmission over long distances.
