A river provides for the electric energy for a small town. if a bulb is switched off, according to the law of conservation of energy, where does a change of energy occur and where and in what form??

In production of power, the electric power is produced, but we do all measurments in terms of potential difference generated.

So in this case, when bulb is switched off, the current throught he wire accross that potential difference reduces.

Thus the power consumption drops which is the rate of conservation of energy, but the amont of energy consumed remains same.

Thus even then the conservation of energy is followed.