power consumption of a blockchain transaction on Ethereum and Polygon - Page 1
Forum section: electronics / general

author: FrankBuss
author_rank: Unknown
timestamp: May 05, 2022, 12:14:26 pm
content: I'm trying to calculate how much energy is needed for one transaction on the Polygon blockchain, and how much on the Ethereum blockchain.I found an article for Ethereum, which says for a high estimate of the power consumption, the Ethereum network needs about 19.44 TWh per year, see here:https://www.notion.so/Carbon-FYI-Methodology-51e2d8c41d1c4963970a143b8629f5f9There are about 1.2 million transactions per day on the Ethereum network, see chart top right here:https://etherscan.io/This means one Ethereum transaction needs about 44 kWh (19.44 TWh / (365 * 1.2e6)).Another source says it needs 30 kWh per transaction, so looks about right:https://cointelegraph.com/news/ethereum-transaction-energy-use-equals-to-2-5-miles-in-a-tesla-model-3-reportNow the Polygon network is a layer 2 solution on top of Ethereum, which needs needs a checkpoint transaction in the Ethereum network every 30 minutes, according to this documentation:https://docs.polygon.technology/docs/develop/ethereum-polygon/pos/deposit-withdraw-event-pos/So 48 transactions per day on Ethereum for 3 million Polygon transactions means it needs 0.7 Wh per transaction for the Ethereum part of the protocol.(48 * 44 kWh / 3 million = 2.1 MWh for 3 million = 0.7 Wh)There are 90 validators for Polygon, each needs 2 PCs with 500 W each, so 1 kW, according to this article:https://blog.polygon.technology/polygon-the-eco-friendly-blockchain-scaling-ethereum-bbdd52201ad/Running for a day, this needs 2.16 MWh. So the Polygon part of one transaction is 0.072 Wh per transaction.(2.16 MWh / 3 million = 0.072 Wh)In sum, and if we round up to be conservative and take into account all the routers of the internet etc. as well, we could say that one transaction on Polygon, including the Ethereum part, needs about 1 Wh max.A good gaming PC with monitor needs about 500 W. This means one transaction is about equal to play a game for 7 seconds (1 Wh / 500 W = 0.002 h = 7.2 s). Using an Ethereum transaction, it would be equal to playing a game for more than 3 days (44 kWh / 500 W = 88 h = 3.6 days).Is this right, or did I made some error somewhere?

author: tom66
author_rank: Super Contributor
timestamp: May 05, 2022, 02:58:06 pm
content: I don't see anything wrong with your calculation.For bonus points, how efficient is VISA? (As an example of 'conventional' banking.)Statistics from VISA show they processed 11.68 billion transactions for 'product' and 741 million for cash in Europe. Assume transactions have equal energy cost, that is 12.4 billion transactions per year.The energy consumption figures for VISA's datacenters are not available, but they only have 4 globally. One is located in the UK (processes UK & EU transactions), just outside of the town I grew up in incidentally (Basingstoke, UK.) I don't think any others are located in Europe but VISA are quite closed about this (for obvious opsec reasons!)A typical large datacenter might have peak 10MW consumption. So over 1 year that's 87.6 GWh, so one transaction costs about 7.1Wh with some generous assumptions.That is much less than Ethereum on its own but more than Polygon (but then again if you batched all of your VISA purchases in a year into one transaction like Polygon does, then maybe you'd be much more efficient too.)

author: Bud
author_rank: Super Contributor
timestamp: May 05, 2022, 04:40:01 pm
content: I'd think conventional banking uses more energy, that is because they use commercial ewuipment which is not energy efficient to start with, plus they run on-premise redundant infrastructure and disaster recovery sites.

author: AndyC_772
author_rank: Super Contributor
timestamp: May 05, 2022, 04:52:24 pm
content: I wonder how any of these methods compare to the energy cost of using cash?Cash has to be minted in the first place, then repeatedly transported to banks and ATMs, then our own pockets, then retailers, then back to the banks, rinse and repeat.It sounds like quite a good interview question - make reasonable assumptions about the value of transactions by a particular business, the relative locations of banks, customers and business site, and the methods of transport used in each case. Then calculate the energy cost of buying a thing with cash vs credit, and see if there's a threshold value where the two are equal.