TL;DR: Ethereum will use at least around 99.95% less energy after the merger.
Ethereum will complete the transition to proof-of-stake in the coming months, bringing myriad improvements that have been theorized for years. But now that the Beacon Channel has been running for a few months, we can actually dig deeper into the numbers. One area we are excited to explore is new estimates of energy consumption, as we end the process of spending a country’s energy based on consensus.
There are no concrete statistics yet on energy consumption (or even hardware used), so the following is a rough estimate of the energy consumption of Ethereum’s future.
Since many people use multiple validators, I decided to use the number of unique addresses that have made deposits as an indicator of how many servers are available today. Many responders could have used multiple eth1 addresses, but this largely negates those with redundant configurations.
At the time of writing, there are 140,592 validators from 16,405 unique addresses. Obviously this is heavily biased by exchanges and staking services, so removing them leaves 87,897 validators supposedly staking from home. As a sanity check, this implies that the average home gamer uses 5.4 validators, which seems a reasonable estimate to me.
Power Requirements
How much power is needed to run a Beacon Node (BN), Validator Clients (VC) 5.4, and an eth1 full node? Using my personal setup as a base, that’s about 15 watts. Joe Clapis (a Rocket Pool developer) recently ran 10 VC, a Nimbus BN, and a Geth full node on a 10Ah USB battery for 10 hours, meaning this setup averaged 5W. Likely the average gamer is using such an optimized setup, so let’s call it 100W total.
Multiplying that with the 87,000 validators from before, that means home investors consume about 1.64 megawatts. It is a little more difficult to estimate the power consumed by custodians, they manage tens of thousands of validator clients with redundancy and backups.
To make our lives easier, let’s also assume they use 100W for 5.5 validators. Based on the staking infrastructure teams I’ve spoken with, this is a raw overestimate. The real answer is something like 50 times less (and if you are a staking team consuming more than 5W/validator, contact me, I’m sure I can help you).
In total, an Ethereum Proof-of-Stake therefore consumes something on the order of 2.62 megawatts. This is not on the scale of a country, a province or even a city, but that of a small town (approximately 2,100 American households).
For reference, proof-of-work (PoW) consensus on Ethereum currently consumes the energy equivalent of a mid-sized country, but this is actually necessary to keep a PoW chain secure. As the name suggests, PoW reaches consensus based on which fork has the most “work” done. There are two ways to increase the rate of “work” done, increase the efficiency of mining hardware and use more hardware at the same time. To prevent a chain from being successfully attacked, miners must perform “work” at a higher rate than an attacker could. Because an attacker is likely to have similar hardware, miners must run large amounts of efficient hardware to prevent an attacker from outplaying them, and all that hardware consumes a lot of power.
Under PoW, because the price of ETH and the hashrate are positively correlated. Therefore, as the price increases, in equilibrium the energy consumed by the network also increases. Under Proof-of-Stake, when the price of ETH increases, network security also increases (the value of ETH at stake is worth more), but energy requirements remain unchanged.
Some comparisons
Digiconomist estimates that Ethereum miners currently consume 44.49 TWh per year, which equates to 5.13 gigawatts on an ongoing basis. This means that PoS is approximately 2,000 times more energy efficient based on the conservative estimates above, reflecting at least a 99.95% reduction in total energy consumption.
If the power consumption per transaction is higher than your speed, that’s ~35 Wh/tx (average ~60,000 gas/tx) or about 20 minutes of TV. In contrast, Ethereum PoW uses the energy equivalent of a house for 2.8 days per transaction and Bitcoin consumes 38 house days.
Look forward to
Although Ethereum continues to use PoW for now, this won’t be the case for much longer. Over the past few weeks, we saw the emergence of the first testnets for The mergerthe name given when Ethereum transitions from PoW to PoS. Multiple teams of engineers are working overtime to ensure that The merger arrives as soon as possible and without compromising security.
Scaling solutions (such as rollups and sharding) will help further reduce energy consumed per transaction by leveraging economies of scale.
Ethereum’s power-hungry days are numbered, and I hope that’s true for the rest of the industry as well.
Thanks to Joseph Schweitzer, Danny Ryan, Sacha Yves Saint-Leger, Dankrad Feist and @phil_eth for their contribution.
