How Does the Network’s Difficulty Target Relate to the Energy Expenditure in PoW?

The difficulty target is a threshold value that a block's hash must be less than or equal to for the block to be considered valid. A lower difficulty target means the required hash must start with more zeros, making it much harder to find and demanding more hashing attempts.

Since each hashing attempt requires computational power, a lower difficulty target directly translates to a greater required energy expenditure to find a block.