Bitcoin mining validates transactions and adds them to the blockchain ledger. Miners solve cryptographic hash puzzles using computational power and are rewarded with newly minted bitcoins. The network's annual electricity consumption reached 91.6 TWh as of June 2022, exceeding the total usage of Belgium and the Philippines.
Blockchain Essentials
The blockchain is a public distributed ledger where transactions are recorded chronologically and cannot be altered. Each block contains a previous hash, transaction data, a nonce, and a 256-bit hash generated by the SHA-256 algorithm. The proof-of-work mechanism requires miners to find a nonce that produces a block hash below a network-defined target. The first miner to succeed earns 6.25 BTC (current reward, with the next halving expected in 2024).
Hardware and Mining Setup
Miners need a GPU or an ASIC miner, mining software, and a digital wallet. Most join a mining pool for steadier payouts. Minimum requirements include an internet connection with at least 50 KB/s speed and no data caps. After configuration, the mining process runs autonomously; human intervention is only needed for failures or maintenance.
Transaction Bundling and Merkle Tree
Each Bitcoin transaction has an input, output, and amount. Mining software hashes every input, groups them into a block, and builds a Merkle tree by repeatedly pairing transaction IDs using SHA-256. The resulting Merkle root is stored in the block header along with version, previous block hash, timestamp, nonce, and target. Miners iterate the nonce until the generated hash is less than the target, verifying all transactions in that block.
Supply Cap and Halving
Bitcoin's total supply is limited to 21 million. The initial block reward was 50 BTC. Halvings occurred in 2012, 2016, and 2020, reducing the reward to 6.25 BTC. Once all bitcoins are mined, miners will rely solely on transaction fees. This deflationary design ensures scarcity but reduces mining profitability over time.
Key Risks and Limitations
Energy consumption is the primary concern: 91.6 TWh annually surpasses many countries. Hardware damage can result from poor ventilation. Metered internet connections risk overage charges due to constant data uploads/downloads. Mining difficulty adjusts every 2,016 blocks (roughly two weeks) to maintain a 10-minute block interval, regardless of total network hashpower.