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Comment by majewsky | Hacker News Reader

> [With PoS, Ethereum would lose] the baggage of wasting the electricity of a small city to keep itself running.

"Small city" sounds suspiciously small. Last time I checked, Bitcoin had the same electricity consumption as the entire country of Austria. I can believe that Ethereum has less miners, but by that over 2 magnitudes?

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I can't comment specifically on the details, but one consideration is that Ethereum's mining hash is designed to be ASIC resistant.

Bitcoin is entirely mined by dedicated hardware that's incapable of doing anything other than mining Bitcoin. Ethereum is mostly mined by GPUs that can obviously be repurposed for other applications if need be.

If the electricity cost for Ethereum mining gets too out of control, the miners can just point their GPUs at some other task. Whereas Bitcoin miners are stuck with sunk cost of rapidly depreciating capital, and pretty much will never turn even during electricity price spikes.

But the ASICs are used because they are more efficient. Forcing miners to use less efficient hardware is going to drive up the average energy per hash calculated.

The system is meant to balance itself out one way or the other. You throw more efficient resources at it, and it becomes less efficient to maintain its 10-20 second block times. It's actively anti-efficient.

The idea behind ASIC resistance is not efficiency, but rather to limit centralization. If you can use generic hardware that anyone can access it is intended to reduce capex required to become a cost-effective miner. Now of course, I don't think that makes sense, but that's the idea.

Ah, you're right. After having enough hashes to secure against attacks, they don't really do anything useful. People will just mine as many as they can with a given budget, which buys the same number of kWh no matter how efficient the hash calculations are.

You're completely ignoring the difficulty mechanism in Bitcoin. When everyone has a 1TH/s miner that consumes 1kWh and suddenly a 10TH/s miner that consumes 1kWh comes out everyone is going to switch to the new miner. Because Bitcoin guarantees that a block is mined every 10 minutes it has to make the calculation 10x harder than before. The end result? The energy consumption didn't change.

What makes Bitcoin more energy intensive then? The price of Bitcoin. When the price of Bitcoin doubles that also means the mining profit doubles. More miners (= more energy consumption) join the blockchain until the profit margin is back to the previous level. The price of a Bitcoin is 70x higher than the price of Ethereum so that suggests that Bitcoin should use 70x more energy.

I don't think you can directly compare the prices of the coins, but you need to look at the reward that's at stake.

12.5 bitcoins every 10 minutes at 7277 USD/bitcoin = 9096 USD/minute

3 eth every 14 seconds at 132 USD/eth = 1697 USD/minute

then you'd expect the bitcoin miners to use 5.3x the energy of eth

EDIT: oh, someone already did the same calculations earlier a couple of comments below :)

Basically correct, except that it isn't the price of Bitcoin or Ethereum that matters, per se, but rather the value of the reward for each block relative to the amount of time required to mine it. For Bitcoin, ignoring transaction fees, the rate is 12.5 bitcoins per 10 minutes; for Ethereum it's 3 ETH per 15 seconds. If the price of 1 BTC is 70x the price of 1 ETH then you would break even expending about 7.3x over a given interval to mine 12.5 BTC vs. 1x to mine 120 ETH. If you spent 70x, however, you'd soon be bankrupt despite the higher BTC price, because you don't earn 70x the value.

So energy usage should drop quite a bit after some difficulty increases?

The difficulty increases or decreases to maintain the target block interval. The only way that impacts mining revenue is if the actual block interval deviates significantly from the target—for example, if the hash rate suddenly increased such that blocks were being solved in five minutes instead of ten, that would double the revenue rate (and thus the economical power consumption) temporarily until a difficulty increase brought the interval back to ten minutes per block.

What does cause significant changes in revenue is the periodic halving of the block reward. Absent an opposing increase in price and/or transaction fees, when the reward drops from 12.5 BTC/block to 6.25 BTC/block in May of this year the energy budget for profitable mining should be cut roughly in half.

Sorry yeah I was mixing those up. But is it going to use not-obscene amounts of electricity eventually?

Etheriums PoW algorithm isn't ASIC resistant, just largely unimplemented. Indeed a large reason NIST made Keccak SHA3 is that ASIC/FPGA acceleration is on par or even faster than SHA256 acceleration.

It may take a bit more ram and need a decent bus as a result which is why people mine on GPUs that have both. Rather than cheap ASICS that are cheap because they have neither. "Resistant" ain't the word to use.

Ethereum mines 2 ETH (exactly) per 10 seconds (approximately).

Bitcoin mines 12.5 BTC (exactly) per 10 minutes (approximately). Normalizing the ETH rate against the BTC, we get 2 ETH * 6 * 10 = 120 ETH.

So at current market rates, 120 ETH * $132 vs. 12.5 BTC * $7,341, $15,840 ETH for $91,792.5 BTC.

This suggests that the BTC network should use roughly 5.8 times as much energy as ETH, to derive an equivalent profit per unit energy.

The article actually has a good link to https://www.trinsicoin.com/?focus=ETH where if you scroll down it breaks down the math.

(You have to hover over Blockchain, Mining, and Energy to see the parameters.)

> but by that over 2 magnitudes?

Why do you question the claim?

The power consumption doesn't scale between the two by the quanta of miners, it scales differently because the algorithms are different and thus the power consumed is different.

I have no idea how the algorithms differ nor how the difficulty differs among the two, so I don't have an intuition about how to guess whether or not they should scale relative to each other. I suspect that ethereum's market cap would be lower and probably have lower mining rewards therefore less capital invested in its global mining pool. I suspect that ethereum's algorithm requires more energy per block than bitcoin's, but I have a hard time guessing how much. Especially since it's a little less mature, maybe fewer ASIC miners so even less efficient in practice.

There’s also the fact that Ethereum has an almost completely different architecture including block times which affect the frequency of mining, different reward structures, etc. As far as I know its not necessarily the difference between Bitcoin’s SHA-256 vs Ethereum’s Ethash as much as it is about the architecture itself.

There's so many inputs that it's difficult to casually come up with an intuition-guided estimate. So it makes some sense to have faith in the empirically guided value. We hope that they took the time to validate their algorithm for extrapolating the energy consumption.

The trinsicoin algorithm is really just a minimum bound based on the most efficient rigs known for a given algorithm and the cheapest industrial rates for electricity. The Litecoin Foundation actually helped out with some of the math and data resources.

The total power consumption of any given crypto currency scales according to the ongoing value of new block rewards per fixed unit of time. You can ignore the rest of the factors (like algo, block time) for the most part. Miners run if they can make money for a given cost of electricity, and don't if they can't.

Indeed; see for example this screener showing daily issuance in dollars:

https://messari.io/screener/play-around-074BC5B4

from which we can infer that Bitcoin uses about 10x more electricity than Ethererum.

According to https://ethernodes.org/ there are ~7.5k nodes & according to https://www.etherchain.org/charts/distinctMiners ~60 miners running ATM. Small city sounds a bit big in that context.

This link to the list of Ethereum mining pools might help make more sense of that: https://www.poolwatch.io/coin/ethereum

As you can see there are ~570k workers contributing to ~79k mining addresses. A lot of the data you see about "distinct miners" might be pools rather than your loner GPU miner.

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