there was a change in the supply curve (downwards)

Actually the supply curve moves to the left, which makes it move "upwards" on the S-D curve...

The gasoline consumer sees a price every time he drives by a gas station (not even every time he stops at the pump), but the electricity consumer doesn't see the instantaneous wholesale price of electricity when he switches an appliance on. He gets a monthly bill. And then again, the monthly bill is often a flat rate (possibly by tiers: the first so many kW-h cost this much, the next so many cost that much, etc). so the wholesale supply curve is invisible to the consumer, even industrial-scale consumers. And even the gasoline consumer with his frequent information updates on the price of gasoline won't be likely to reconsider his driving habits more often than once a month, when looking at the state of his accounts, unless he sees a price spike in which case he may engage in panic buying or decide to park the car altogether for a few days. Finally, energy is akin to a Giffen good in that people are likely to consider their energy consumption "fixed" and not part of their "disposable income" that they shuffle around. So increasing energy costs just lead to lower disposable income and so in the short term reduce demand of other consummables, not demand for energy. Energy is not a Giffen good in that people don't consume more energy when it is more expensive.

We have met the enemy, and he is us — Pogo