Why Mining Uses Energy

The energy criticism of Bitcoin mining was covered in Part 4 from an environmental perspective. Here it’s worth understanding from a technical one — because the energy use isn’t incidental. It’s structural.

Proof of work requires real computational effort, which requires real energy. That’s not a flaw in the design. It’s the design.

Here’s why.

If producing a valid block were free — or nearly free — then attacking the network would also be nearly free. Anyone with a laptop could generate fraudulent blocks faster than the honest network. The security would collapse.

By requiring real energy expenditure to produce each block, Bitcoin makes attacks expensive in proportion to their ambition. To rewrite one week of Bitcoin history would require redoing one week’s worth of the entire global mining network’s energy expenditure. At current hash rates, that’s more energy than most countries produce in a year.

The energy expenditure is the security deposit. Miners burn real resources to earn the right to write Bitcoin history. The more energy the network collectively expends, the higher the cost of rewriting that history.

This is why Bitcoin’s security has increased every year since 2009. Not because the code was updated — it largely wasn’t. But because more mining hardware joined the network, more energy was committed, and the cost of attacking it grew accordingly.

The energy isn’t waste. It’s the physical anchor that makes a purely digital system secure against physical-world attackers.

Tomorrow: the difficulty adjustment — Bitcoin’s self-correcting clock.

— The Daily Bit