“[…] As a crypto-asset becomes more valuable, the mining rewards also become more valuable. This attracts more miners and computing resources to solve the cryptographic math problem. As miners dedicate more computing resources to process transactions for a blockchain, the math problem adjusts to become more difficult. This keeps the average time required to find a solution approximately constant.”
“This PoW “economic model” means that a PoW network will generally use more electricity as the crypto-asset’s value (and network) grows, so long as the distribution of the crypto-asset among miners stays constant. The growth in total value of crypto-assets has attracted thousands of miners, who use computers and customized hardware, drawing total electricity amounts comparable to a mid-sized nation or a large metropolitan area.”
The most popular alternative to the energy-intensive PoW consensus mechanism is PoS, which is used for networks such as Solana, Cardano, the proposed Ethereum 2.0, and others.
“In PoS, participants — called validators — typically “stake” an amount of crypto-assets for the opportunity to be chosen to add a new block of transactions to the ledger. The more cryptoassets a validator stakes, or the longer the stake is locked up, the larger the chance of being chosen.[…]”