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«a single Bitcoin transaction consumes 165kWh» This needs to be repeated in every HN thread about Bitcoin: no, transactions don't consume energy. The proof-of-

by mrb 6y ago

«a single Bitcoin transaction consumes 165kWh» This needs to be repeated in every HN thread about Bitcoin: no, transactions don't consume energy. The proof-of-work is completely independent of the number of transactions. A block could have 1 or 1000 transactions, but the energy consumption would be the same. People have this wrong idea that more transactions imply more energy consumption. That's just not true.

deleted 6y ago
[deleted]
ctz 6y ago
> The proof-of-work is completely independent of the number of transactions. A block could have 1 or 1000 transactions, but the energy consumption would be the same. There's a block limit, though, right? It doesn't scale up infinitely -- you might have 1000 transactions in a block, but not a million. Therefore, it is accurate to attribute the energy per block to securing the transactions within.
- rodiger 6y ago
  Also worth noting though that "extra" energy per-tx increases the security of that tx. You aren't just paying for the system to function, you're paying for the system to be resistant to bad actors.
  - PragmaticPulp 6y ago
    Only so far as the majority of the miners are not coordinated. With the current concentration of mining capacity in China, that's not exactly a sure thing any more.
    - shawnz 6y ago
      The point is that the energy they are spending on mining disincentivizes them from doing anything except using it to earn Bitcoins legitimately. If they waste that energy attacking the network instead, it would be less profitable.
- ric2b 6y ago
  Yes, but the limit is chosen to keep a balance between scale and decentralization (keeping the cost of running nodes low). It can be safely increased over time as bandwidth, storage and processing costs go down. For now there's still a lot of viable efficiency enhancements to be implemented/adopted so increasing the limit isn't strictly necessary.
PragmaticPulp 6y ago
> A block could have 1 or 1000 transactions, but the energy consumption would be the same. The calculations are based on the maximum throughput of the Bitcoin protocol, which is a fixed value due to the 10-minute block time and the limited block size. The average number of transactions per block is always around 2K: https://www.blockchain.com/charts/n-transactions-per-block https://www.blockchain.com/charts/n-transactions-per-block > The proof-of-work is completely independent of the number of transactions. Right, which makes this whole thing even more ridiculous. If number of transactions went to zero we'd still have to burn 120+ TWh per year just to keep the system going. The 165kWh per transaction calculation is the best case scenario assuming every block is filled to the maximum with transactions.
- r3ctilinear 6y ago
  Incorrect. The proof of work difficulty scales automatically. If the miners/hash-power reduces then blocks become easier to mine. The Bitcoin blockchain could subsist on a minuscule fraction of todays energy usage if the majority of miners decided to throw away their investments and stop mining.
  - Kbelicius 6y ago
    But it would not be possible for it to maintain its price and usefulness at that minuscule fraction of todays energy usage.
  - boublepop 6y ago
    Is this a joke? Yes, bitcoin could function without using any energy at all if there where no transactions and no miners. That doesn’t change that currently independent of transaction numbers a huge amount of energy is being wasted, and the minimal waste per transaction in a theoretical maximum transactions/energy scenario would still have you spending more than our entire energy production just heating up silicon if we relied entirely on Bitcoin for financial transactions.
    - uh-quan 6y ago

by mrb 6y ago

deleted 6y ago

[deleted]

ctz 6y ago

> The proof-of-work is completely independent of the number of transactions. A block could have 1 or 1000 transactions, but the energy consumption would be the same. There's a block limit, though, right? It doesn't scale up infinitely -- you might have 1000 transactions in a block, but not a million. Therefore, it is accurate to attribute the energy per block to securing the transactions within.

rodiger 6y ago
Also worth noting though that "extra" energy per-tx increases the security of that tx. You aren't just paying for the system to function, you're paying for the system to be resistant to bad actors.
- PragmaticPulp 6y ago
  Only so far as the majority of the miners are not coordinated. With the current concentration of mining capacity in China, that's not exactly a sure thing any more.
  - shawnz 6y ago
    The point is that the energy they are spending on mining disincentivizes them from doing anything except using it to earn Bitcoins legitimately. If they waste that energy attacking the network instead, it would be less profitable.
ric2b 6y ago
Yes, but the limit is chosen to keep a balance between scale and decentralization (keeping the cost of running nodes low). It can be safely increased over time as bandwidth, storage and processing costs go down. For now there's still a lot of viable efficiency enhancements to be implemented/adopted so increasing the limit isn't strictly necessary.

PragmaticPulp 6y ago

> A block could have 1 or 1000 transactions, but the energy consumption would be the same. The calculations are based on the maximum throughput of the Bitcoin protocol, which is a fixed value due to the 10-minute block time and the limited block size. The average number of transactions per block is always around 2K: https://www.blockchain.com/charts/n-transactions-per-block https://www.blockchain.com/charts/n-transactions-per-block > The proof-of-work is completely independent of the number of transactions. Right, which makes this whole thing even more ridiculous. If number of transactions went to zero we'd still have to burn 120+ TWh per year just to keep the system going. The 165kWh per transaction calculation is the best case scenario assuming every block is filled to the maximum with transactions.

r3ctilinear 6y ago
Incorrect. The proof of work difficulty scales automatically. If the miners/hash-power reduces then blocks become easier to mine. The Bitcoin blockchain could subsist on a minuscule fraction of todays energy usage if the majority of miners decided to throw away their investments and stop mining.
- Kbelicius 6y ago
  But it would not be possible for it to maintain its price and usefulness at that minuscule fraction of todays energy usage.
- boublepop 6y ago
  Is this a joke? Yes, bitcoin could function without using any energy at all if there where no transactions and no miners. That doesn’t change that currently independent of transaction numbers a huge amount of energy is being wasted, and the minimal waste per transaction in a theoretical maximum transactions/energy scenario would still have you spending more than our entire energy production just heating up silicon if we relied entirely on Bitcoin for financial transactions.
  - uh-quan 6y ago