Bitcoin

number of transactions per day (2022) : 240 000
per year : 87 000 000
going slightly down for the last 3 years
With the number of new bitcoins issued per block decreasing by half approximately every four years, the final bitcoin is not expected to be generated until the year 2140
a new block (6.5 bitcoin) is produced approximately every 10 minutes. A new bitcoin is mined on average every 1.6 minutes

Proof of work / state

In proof of work
- Anyone can try to resolve the algorithm for any transaction
- very poor energy efficiency as only one miner will validate the transaction
- Difficulty is one of the most important aspects of Proof-of-Work mining. It is derived using the network hash rate and determines the speed at which miners are able to validate an encrypted block. In the context of bitcoin mining, the difficulty adjusts every 2016 blocks and aims to maintain an average block time of 10 minutes. The computers will always consume more ! (more processing)
In proof of stake
- A small number of clients will be able to validate the transaction (chosen randomly)
- the first one will get the reward
- thought to reduce the energy consumption by 99%

See this report

2020 : estimated at 402 kg per transaction (45 MT yearly)
En 2022 c’est 1,2T/transaction selon cette source (115 MT yearly)
It’s 0,5% of the world electricity consumption
in 2020 number of transactions went down
but energy per transaction went up (because the bitcoin value is high resulting in higher mining incentive)
The inherent problem with this, as Charles Hoskinson, co-founder of Ethereum, told CNBC, is that “the more successful bitcoin gets, the higher the price goes; the higher the price goes, the more competition for bitcoin; and thus the more energy is expended to mine [it]
carbon footprint per transaction : up 34%

The bitcoin mining can be more “responsible” due to the electricity price fluctuation

Miners favor cheap electricity and this happens mostly when there is an excess of it, notably when renewables are producing more
They can move around to take advantage of this
Still, there is great advantage to use fossil fuels (a lot of mining in China, US, Kazakhstan)