Bitcoin’s network hashrate crossed 1 zettahash per second earlier this year - a number so large it requires a unit most people had never heard of before 2025. One zettahash is one sextillion hash computations per second. The scale is almost meaningless to picture, which is partly the point: the mining industry has become something unrecognizable compared to what it was at the last halving in 2024, let alone 2020.

The Halving Did Not Kill Miners This Time

After the April 2024 halving cut the block subsidy from 6.25 BTC to 3.125 BTC, the standard narrative was that marginal miners would be forced offline and hashrate would drop sharply before recovering. That happened - briefly. Within roughly four months, hashrate had not only recovered but continued climbing. The difference this cycle was that the largest publicly traded miners - Marathon Digital, Riot Platforms, CleanSpark - had spent 2022 and 2023 aggressively expanding capacity and locking in cheap power contracts, specifically to absorb a post-halving squeeze that would eliminate smaller competitors.

It worked. What the 2024 halving actually did was accelerate consolidation, not contraction.

Fee Revenue Is Still Not Filling the Gap

The long-running thesis that transaction fees would eventually replace block subsidy as miner revenue remains unproven at scale. Bitcoin’s average transaction fee fluctuates considerably - Ordinals and Runes activity created brief spikes in 2023 and 2024 - but fees as a percentage of total miner revenue have not shown a reliable upward trend. The 2028 halving will cut the subsidy to 1.5625 BTC per block. At that point, the sustainability question becomes significantly harder to wave away.

This is the structural tension sitting underneath the hashrate milestone. A more secure network, on paper. A revenue model that still depends heavily on new BTC issuance.

Geography Has Shifted

The U.S. now accounts for an estimated plurality of global Bitcoin hashrate, a position it consolidated after China’s 2021 mining ban pushed operations to North America, Central Asia, and parts of the Middle East. Texas remains the dominant American hub, partly due to its deregulated grid structure and the ability miners have to sell power back during demand peaks - a relationship that’s become genuinely symbiotic with ERCOT grid operators rather than purely parasitic, as critics once framed it.

Kazakhstan’s share has declined from its post-China-ban peak as the government imposed stricter licensing and higher energy costs on miners. The map keeps moving.

One zettahash is a clean number to celebrate. The economics behind it are considerably messier.