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Comment by ahnick | Hacker News Reader

> That's why Chia is only more efficient than PoW when it isn't in demand.

Actually that's incorrect. Chia is always more efficient than PoW, b/c in PoW everyone is constantly racing to solve every block. (i.e. find the proof) Whoever finds the proof gets the block reward and everyone else just throws away all that work for nothing and then the next race starts for the next block reward.

Contrast that with Chia, where when you are plotting you are storing your proofs in a file for later challenges. You aren't discarding that work and you can hold onto it for a long time (years). It's not until you are "farming" the plot that you start answering challenges. The challenges just translate to simple reads from disk, which are quick constant time lookups. Now it may take you a long time (or never) to find a reward for a single proof, but at least you didn't have to throw all that work away and start over.

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I agree in part and disagree in part.

First, when the network space is growing exponentially, the value of preexisting work is decaying exponentially. I do grant you that completed work is nonzero in value, but during a growth phase its value might as well be zero. Whenever speculators believe the currency will actually have any long term value above its current exchange rate minus the resource costs, then it will be in a growth phase. The total resource consumption during this growth phase, including the supply chains to produce space, need to be studied. Measured in transactions per unit of CO2 emissions, I expect its efficiency to be better only during a phase of stable network space, i.e. when its value is not speculated to be higher than its current value.

Second, not all PoW is discarded. I want to be clear at the outset that this isn't a defense of PoW, but there's a system called AuxPoW which allows work to be applied to multiple chains, modestly improving its efficiency. This mining protocol is being used actively by scrypt hashed coins, e.g. dogecoin and litecoin. I'm certainly not saying PoW is superior to the proof system in Chia, but just that the distinction between them is not as strong as claimed. Nevertheless, both are incredibly destructive and yet interesting.

> First, when the network space is growing exponentially, the value of preexisting work is decaying exponentially. I do grant you that completed work is nonzero in value, but during a growth phase its value might as well be zero. Whenever speculators believe the currency will actually have any long term value above its current exchange rate minus the resource costs, then it will be in a growth phase. The total resource consumption during this growth phase, including the supply chains to produce space, need to be studied. Measured in transactions per unit of CO2 emissions, I expect its efficiency to be better only during a phase of stable network space, i.e. when its value is not speculated to be higher than its current value.

To be fair you'd also have to measure and compare Chia's growth phase to Bitcoin's (or other PoW chains) growth phase as well. This would mean taking into account the manufacturing of the equipment, distribution and deployment costs of ASIC miners, electrical power generation costs, etc. Also, Chia runs on general computing hardware whereas ASICs have to be specifically designed and manufactured and ASICs use a whole lot more electricity than servers with hard drives running Chia. I think a single Ant miner uses something like 32 kWh a day IIRC. Chia has done a lot of power consumption analysis already and you can dive deep on that information yourself over at https://chiapower.org/ if you're curious. There's a dramatic difference between Bitcoin's PoW network and Chia's PoST network.

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