Proof-of-Work is a consensus algorithm that dictates the rules by which transactions are validated on the blockchain. Typically, a PoW-based blockchain consists of nodes called miners, which compete with each other to solve a complex mathematical puzzle. The first to succeed gets the right to add the next block to the blockchain. For adding a new block, the miner gets a reward. PoW requires high energy consumption and powerful hardware. This is because the more energy you consume (and therefore computational power), the more chances you have to validate a block and earn money.