Ethereum currently uses the Proof-of-Work (PoW) consensus algorithm, the same algorithm used by Bitcoin. However, Ethereum plans to transition to the Proof-of-Stake (PoS) consensus algorithm in a network upgrade known as Ethereum 2.0. In PoW, miners compete to add new blocks to the chain, whereas in PoS, validators are chosen to create new blocks based on the number of ether they hold and are willing to 'stake' as collateral.