[NikolaNovak]

>>"Why does Bitcoin have to justify its energy usage when the legacy financial system does not?"

These questions always strike me as disingenuous / intentionally obtuse. But charitably assuming an honest question for purpose of frank discourse, my simplest answer / understanding is that in general, in the daily transactional system, participants work to reduce energy cost per transaction and over most periods of time this energy cost per transaction has been reducing, or if it increases, it is to support some additional identifiable functionality. This strikes me as a rational system.

With bitcoin, my understanding is that effective energy usage per transaction / for the system as a whole has been increasing. This strikes me as iterational.

I am eager to be corrected if my high level perception of bitcoin is incorrect and energy costs have been rationally decreasing / becoming more efficient over time.

If NOT.. Then how does anybody persuade themselves to believe this is a rational currency system, or at the very least, that it's energy usage in particular is in any way whatsoever defensible??

[frankenst1]

The increase in hashrate can be interpreted as an increase in security, i.e. it is much more difficult/expensive for an attacker (even nation-level) to harm Bitcoin. This is mandatory for a financial network that aims to operate on global scale.

Bitcoin does not consume energy per transaction but per block. How many transactions the block contains does not change the energy requirement to mine it. If the number of transactions on the Bitcoin network would go to zero tomorrow, energy consumption would not change (same if transactions were doubled).

Bitcoin's energy usage is a function of hashrate which is affected by mining profitability which is affected by block reward (mined coins + tx fees) and energy prices.

Long story short: Just make "dirty" energy more expensive by including the cost it incurs on the climate. This would make Bitcoin's already large share of renewables even bigger and would improve global energy production and consumption as a result.

[NikolaNovak]

I appreciate the response but we may disagree as to what is the summary / "long story short".

My "long story short" question is: over time, has Bitcoin effective energy per transaction gone up or down?

Not theory, not what nebulous public policy changes should happen to justify the energy mix, not what we think may might need to happen et cetera et cetera.

Is the energy cost per transaction in real world for bitcoin going up or down? (in principle calculated by "energy used for bitcoin system in total divided by number of transactions executed per some unit of time").

Everything else is trying to muddy it up from my personal perspective.

[frankenst1]

> Is the energy cost per transaction in real world for bitcoin going up or down? Everything else is trying to muddy it up from my personal perspective.

Energy is expended to secure the network as a whole and not for the transfer of coins.

But if you insist on computing such a metric with only limited applicability, the answer is: Yes, the metric goes up:

Estimated power consumption per day, 2020-2021 +5%:

    01/01/2020: 0.2 TWh
    01/01/2021: 0.211 TWh

Estimated number of onchain transactions per day, 2020-2021: +6%:

    01/01/2020: 288K
    01/01/2021: 305K

And this doesn't even include all the hidden private transactions that occur off-chain on Layer 2 solutions like the Lightning Network:

Number of nodes on the Lightning Network, 2020-2021 +60%:

    01/01/2020: 5K
    01/01/2021: 8K

Capacity of the Lightning Network, 2020-2021 +430%:

    01/01/2020: $6M
    01/01/2021: $32M

[frankenst1]

> Yes, the metric goes up:

Oops, meant to say transactions go up vs energy, so the metric energy/transaction goes actually down.