What Role Does the Proof-of-Work Consensus Mechanism Play in the Energy Consumption of Bitcoin Mining?

Proof-of-Work (PoW) is the mechanism that mandates high energy consumption as a security feature. Miners compete to expend computational power (hashing) to solve a complex puzzle and validate a new block.

The competitive and continuous nature of this process requires immense electricity to power the specialized hardware. This high energy cost makes a malicious "51% attack" economically prohibitive, ensuring the network's decentralization and security.