Proof of Work (PoW) is a consensus mechanism used by many cryptocurrencies, one of them Bitcoin, to secure the network and validate transactions. In PoW, miners compete to solve complex mathematical puzzles using computational power. The first miner to solve the puzzle gets the right to add the next block to the blockchain and is rewarded with cryptocurrency (for example, Bitcoin).
This process ensures that transactions are verified and that no one can alter the blockchain without expending significant resources.
PoW has its negative aspects, the most important being its energy consumption. The need for powerful computers and vast amounts of electricity to solve puzzles has led to concerns about its energy usage as this can potentially make energy more expensive.