
1. Introduction
The urgency of climate change causes us to reevaluate the energy consumption and efficiency of the products and
services that underpin our daily lives. One example is the growing criticism of the energy consumed by proof of work
(PoW)-based distributed ledger technology (DLT) projects, including Bitcoin1and (with the increased use of
non-fungible tokens, or NFTs2) Ethereum3. It is appropriate, therefore, that cryptocurrencies should also be included
in the energy consumption debate, especially if they aim to play a significant role in the future global monetary
infrastructure.
Research from Alex de Vries for the Digiconomist Platform estimates that the Bitcoin network currently consumes
around 204.50 TWh annually4. This can be compared to the total energy consumption of the country of South Africa,
which consumes an estimated 202 TWh annually5. However, even though these figures are alarming, one should
interpret this comparison as a means to make the energy consumption figures of Bitcoin tangible to the average
person who is not familiar with electricity measurements. The limitation of this comparison is that one compares
apples and oranges. Nevertheless, the question arises: why does Bitcoin as a monetary system need to consume
such a large amount of energy? The answer: In order for Bitcoin nodes to add new transactions to the ledger, they
must solve a cryptographic puzzle that requires a vast amount of computing resources. However, other consensus
mechanisms, such as proof of stake (PoS), have shown that consensus can be achieved without the immense
energy requirements by at least three orders of magnitude6.
The IOTA 2.0 protocol introduces several new concepts, such as a novel consensus mechanism7,8, and a new type of
access control algorithm9. Through the latter, the protocol aims to address (together with other challenges) the energy
consumption inefficiency by removing PoW. The lightweight design allows for low computational demand, meaning
that it can run on low-powered devices (Raspberry Pis, for example). Many of the design decisions were influenced
by IOTA’s vision of enabling the software to run on a wide spectrum of IoT devices.
Previous research into the energy consumption of the current IOTA main network (called “Chrysalis”) was published
on May 14, 202110. However, to protect the network against attacks, the Chrysalis network still uses a centralized
node run by the IOTA Foundation (called “Coordinator”) and uses a small PoW requirement as spam protection.
While the Chrysalis network is already considered green in comparison with other DLTs (for the energy consumption
of one Bitcoin transaction, one billion IOTA transactions can be sent)11, the PoW still contributes significantly to the
overall energy consumption of running the Chrysalis network. With the launch of the IOTA 2.0 prototype on June 2nd,
2021, a prototype software (called GoShimmer) was released and operated in a public testnet12, in which the
12 https://blog.iota.org/iotav2devnet/
11 https://blog.iota.org/an-intro-to-the-iota-ecosystem/
10 https://blog.iota.org/internal-energy-benchmarks-for-iota/
9Cullen, A., Ferraro, P., Sanders, W., Vigneri, L., & Shorten, R. (2021, July 14). Access control for distributed ledgers in the
internet of things: A networking approach. Retrieved February 07, 2022, from https://arxiv.org/abs/2005.07778
8https://blog.iota.org/iota-2-0-details-on-current-status-and-outlook/
7https://blog.iota.org/improvements-to-the-iota-2-0-consensus-mechanism/
6Platt, M., Sedlmeier, J., et. al. (2021). Energy Footprint of Blockchain Consensus Mechanisms Beyond Proof-of-Work.
Discussion Paper Series, from https://arxiv.org/abs/2109.03667
5U.S. Energy Information Administration, Retrieved January 15, 2022 from
https://www.eia.gov/international/data/world/electricity/electricity-consumption
4de Vries, A. (2014). Bitcoin Energy Consumption index. Digiconomist. Retrieved May 22, 2022, from
https://digiconomist.net/ethereum-energy-consumption
3NFTexplained.info. (2022, January 09). “How Much Energy Does An NFT Use?”, from
https://nftexplained.info/how-much-energy-does-an-nft-use/
2https://dappradar.com/ethereum/marketplaces/opensea, retrieved January 25, 2022
1de Vries, A., Gallersdörfer, U., Klaaßen, L., Stoll, C. (2022). Revisiting Bitcoin's carbon footprint. Joule, Volume 6, Issue 3,
2022, from https://www.sciencedirect.com/science/article/abs/pii/S2542435122000861