The Merge and proof-of-stake

Wonder

1. What economic risk replaces the electricity bill as the cost of security?
2. How can a network switch its entire verification mechanism without losing its history?
3. Who holds the power to decide when a validator has acted in bad faith?

Explore

1. Proof-of-stake decouples block production from computational power. Instead of solving cryptographic puzzles, participants lock up native currency as collateral. Every active validator attests to blocks, and the chance of being chosen to propose one scales with its stake. This shifts the primary cost of network security from energy expenditure to capital risk: validators stand to lose their funds if they attempt to validate fraudulent data.
2. Ethereum implemented this through a two-layer architecture. Ethereum’s founders planned a move to proof of stake from the start, but only on 1 December 2020 did the Beacon Chain launch as a separate proof-of-stake consensus layer running parallel to the original execution environment. For nearly two years, these layers operated independently before being unified.
3. On September 15, 2022, The Merge executed. This hard fork joined the original execution layer with the Beacon Chain, deprecating proof-of-work entirely. Miners ceased producing blocks; validators took over. The Ethereum Foundation estimated that Ethereum’s own energy use fell by about 99.95%, and the GPU mining that had secured it until then ended.
4. Each validator has traditionally required 32 ETH; since the Pectra upgrade in 2025, a single validator can hold up to 2,048. They propose new blocks and attest to those proposed by peers. If a validator engages in provable misbehavior, such as signing conflicting blocks, they are ‘slashed’: a portion of their stake is burned and removed from circulation. This penalty mechanism aligns individual economic incentives with network integrity.
5. EIP-1559, activated in August 2021, introduced a base fee that burns part of every transaction cost. Combined with issuance that varies with the total amount staked, this can result in net deflation if network activity is high. The Shapella upgrade in April 2023 enabled the withdrawal of staked ETH and accumulated rewards, ending the initial lock-up period for early participants.
6. Critiques focus on centralization and regulatory exposure. Staking influence scales with wealth, favoring large holders. Services like Lido control a significant share of total stake, creating potential points of failure or influence. Unlike proof-of-work, where hardware can be repurposed, staked capital sits inside the protocol: since 2023 it can be withdrawn, but only through an exit queue, and large staking providers are exposed to legal jurisdiction.

Key facts

Exercise nine, six, three, one

Fact check

Dates, figures and claims checked against the published sources listed below.

• Ethereum Foundation, 'The Merge' documentation (2022)
• EIP-1559: The Fee Market Change (August 2021)
• G. Wood, Ethereum Yellow Paper (2014)
• V. Buterin, Ethereum Whitepaper (2013/2014)