[random023987]

> It's not as if our current system uses a negligible amount of power

Our current system does in fact use a negligible amount of power. Each $2 latte you put on a credit card uses an amount of electricity so infinitesimal that it can only be measured in the aggregate.

The percentage of the power used to generate a single bitcoin block for a single transaction can power an average US household for (approximately) an entire week.

To put it in perspective: If the bitcoin network scaled up to the size of the VISA network it would require 100% of all energy used for all purposes planet-wide, from transportation, manufacturing, agriculture, etc. Everything you could possibly want to buy with bitcoin would be unavailable, as 100% of all human activity would go to powering the miners.

[Shorel]

No, miners hash rate is what eats watts.

Bitcoin network scaling has to do with transactions per second, and it is a protocol problem, and an storage problem, but it is independent of the hash capacity of the system.

We can theoretically improve the Bitcoin network capacity to handle 100x the number of transactions, while having the same hash rate.

In fact, if hash rate were halved each month, and the protocol unchanged, Bitcoin network transaction capacity would still be the same after Bitcoin difficulty is auto adjusted.

Hash rate and transaction capacity are orthogonal issues.

[devrandomguy]

What if you also include the energy consumed by the employees and facilities of Visa, including their commute-to-work energy? And the energy used to construct their facilities, improve network infrastructure, etc? Now are we getting within an order of magnitude of the energy consumption of an army of ASIC miners, and the people who farm them?

[srdev]

On a per-transaction basis? No.

Those costs specifically end up being reified in the fee those processors charge to their customers, so we can determine an upper limit to how much is spent on energy in that way.

[devrandomguy]

The same is true of bitcoin transaction fees, no? Miners set the minimum fee that they will accept, and people tack a fee onto a transaction, large enough that a miner will likely process it.

[srdev]

No, because there is a block reward too that subsidizes the miners, so you have to account for that too.

We don't really know the relationship between transaction rate and electrical usage in a mature BTC system, because mining is mainly used to prevent double-spends and the minimum required mining rate to support a given transaction rate is a game-theoretical concern and not a technical one. We can only really observe what has happened so far in the Bitcoin ecosystem.

[EdSharkey]

Why is so much compute needed for the blockchain? Couldn't a proof-of-work system be developed that consumes VISA-network levels of power? How costly the computation should be (and how much the cost has scaled up) seems like it was an arbitrary design decision.

[Marazan]

No, the amount of energy needed will always be enormous as their is a direct linkage between the value of bitcoin and the amount of energy required to secure the network.

Otherwise there will be a point where it is cost effective to attack the network.

Bitcoin is designed to be wasteful.

[EdSharkey]

I guess I was asking for a hypothetical, new crypto coin. Does proof-of-work have to be costly compute-wise in order to be proof-of-worky?

[lordnacho]

Yes. Think about what it is.

"I'm working on these hashes. You know I'm not taking a shortcut, because there's not yet a known way to do that with this secure hash. And because you know I'm doing the work, you should reward me with some coins."

Alternatives have been considered, like proof-of-stake.