Proof-of-Work (PoW) Ethereum

A consensus mechanism formerly used by Ethereum to secure its network and validate transactions through computational work.

What is Proof-of-Work (PoW) Ethereum?

Proof-of-Work (PoW) was the original consensus mechanism for Ethereum from its launch in 2015 until The Merge in 2022, when Ethereum transitioned to Proof-of-Stake (PoS). In PoW, miners competed to solve complex mathematical puzzles using computational power to validate transactions and create new blocks. The first miner to solve the puzzle earned the right to add a block to the blockchain and received rewards in Ether (ETH) along with transaction fees. This process secured the network but required significant energy consumption, with Ethereum’s PoW consuming an estimated 70-80 TWh annually before the transition, comparable to the energy use of a small country.

Ethereum’s PoW relied on the Ethash algorithm, designed to be ASIC-resistant and favor GPU mining to promote decentralization. However, it faced challenges like high energy costs and environmental concerns, which prompted the shift to PoS. While PoW was critical in establishing Ethereum’s early security and decentralization, its inefficiencies led to its replacement, making it obsolete for Ethereum’s mainnet but still relevant for understanding Ethereum’s history and some Ethereum-based forks like Ethereum Classic.