Every bitcoin miner out there is constantly trying to find a value called a nonce, that once combined with a set of transactions and SHA256-hashed will produce a hash that's lower than a global difficulty target. This is extremely intense in terms of computation and requires vast arrays of specialized chips to do. Once a miner out there finds such a nonce, it broadcasts a set of recent transactions made by people everywhere in a block, and as an aside also obtains 6.25 fresh newly created bitcoins - this is part of how miners make money; the other is the transaction fees users are offering for their transaction to be included in the block the miner broadcasts once he has found the nonce (the amount of transactions that can be included in a block varies but is around ~2200, so a miner that just found a new valid nonce will tend to include the transactions with the highest fees in their block).
This block creation process is both the way transactions are validated / made official between wallets but also the source of newly created bitcoin (originally finding a block rewarded you with 50 BTC; it halves every few years). The nonce guessing process described above is how the energy I mentioned is consumed: by gigantic ASIC farms that constantly try to guess this random value to be able to broadcast the next valid block.
...how?
Every bitcoin miner out there is constantly trying to find a value called a nonce, that once combined with a set of transactions and SHA256-hashed will produce a hash that's lower than a global difficulty target. This is extremely intense in terms of computation and requires vast arrays of specialized chips to do. Once a miner out there finds such a nonce, it broadcasts a set of recent transactions made by people everywhere in a block, and as an aside also obtains 6.25 fresh newly created bitcoins - this is part of how miners make money; the other is the transaction fees users are offering for their transaction to be included in the block the miner broadcasts once he has found the nonce (the amount of transactions that can be included in a block varies but is around ~2200, so a miner that just found a new valid nonce will tend to include the transactions with the highest fees in their block).
This block creation process is both the way transactions are validated / made official between wallets but also the source of newly created bitcoin (originally finding a block rewarded you with 50 BTC; it halves every few years). The nonce guessing process described above is how the energy I mentioned is consumed: by gigantic ASIC farms that constantly try to guess this random value to be able to broadcast the next valid block.