Ethereum Classic (ETC) sustainability report

Ethereum Classic is present on the following networks: Ethereum Classic.

The Ethereum Classic (ETC) blockchain network is fundamentally secured and validated through a Proof of Work (PoW) consensus mechanism, specifically employing the Etchash algorithm, a derivative of the original Ethash. This PoW model mandates that network participants, referred to as miners, expend substantial computational resources to solve complex cryptographic problems. This computational work is indispensable for verifying new transactions, bundling them into blocks, and subsequently adding these blocks to the immutable ledger. The process of mining is central to the network's security architecture, making it highly resistant to tampering and fraudulent activities, such as double-spending. The immense computational power required to append blocks ensures that altering historical transactions would demand an impractical amount of recalculation, thus protecting the integrity of the blockchain. A cornerstone of the Ethereum Classic network's identity is its strict adherence to the "Code is Law" philosophy. This principle gained prominence and was unequivocally upheld after the 2016 DAO hack, when the ETC community made the deliberate decision to retain the original blockchain ledger without any transactional reversals. This commitment to an immutable record, where the blockchain’s history remains unchangeable regardless of external events, fundamentally distinguishes Ethereum Classic from other networks. By preserving the sanctity of its initial ledger, ETC reinforces its core belief in the autonomous and inviolable execution of smart contract code. The Etchash algorithm, chosen for its design features, aims to foster a degree of decentralization in mining by allowing a wider variety of hardware to participate, although it faces ongoing challenges from specialized mining hardware. This combination of a robust PoW mechanism and an unwavering philosophical stance on immutability underpins the network's security, reliability, and unique position in the blockchain ecosystem.

Ethereum Classic is present on the following networks: Ethereum Classic.

The Ethereum Classic network employs a sophisticated incentive model designed to foster continuous miner participation and uphold network security. This model strategically integrates both block rewards and transaction fees, ensuring that those who contribute to the network's operation are adequately compensated. At the core of its incentive structure are block rewards, which miners receive for successfully verifying transactions and adding new blocks to the blockchain. These rewards are distributed according to a deflationary supply model, akin to Bitcoin's halving mechanism, where the quantity of ETC issued through block rewards progressively diminishes over time. This deflationary design serves a dual purpose: it aims to bolster the long-term value retention of ETC and provides a sustained incentive for miners to continue dedicating their resources to securing the network. Alongside block rewards, transaction fees constitute another vital component of miner income. Users on the Ethereum Classic network are required to pay fees in ETC for various activities, including initiating transactions, deploying or interacting with smart contracts, and utilizing decentralized applications (dApps). These user-paid fees not only provide supplementary revenue for miners but also play a crucial role in maintaining network health by discouraging spam transactions and ensuring that network resources are utilized efficiently. The fee structure on Ethereum Classic is dynamic and responsive to network conditions. Transaction fees are calibrated based on the computational complexity and resources required for a specific operation, meaning more intricate interactions typically incur higher costs. Furthermore, these fees can fluctuate based on real-time network demand, acting as a natural mechanism to manage transaction efficiency and prevent congestion during periods of high activity. Miners are incentivized to prioritize transactions offering higher fees, which creates a competitive environment that generally clears the mempool effectively. The scheduled reduction of mining rewards over time is a deliberate design choice, intended to balance the ongoing need for robust network security with prudent management of the ETC supply. This comprehensive approach to incentives ensures a self-sustaining ecosystem where participants are rewarded for their contributions, aligning their economic interests with the network's stability and security.

Ethereum Classic is present on the following networks: Ethereum Classic.

The methodology for calculating Ethereum Classic's energy consumption primarily adopts a "top-down" approach, which is rooted in an economic assessment of the network's mining operations. Within this framework, miners—defined as individuals or devices actively participating in the Proof of Work (PoW) consensus mechanism—are identified as the paramount contributors to the network's energy footprint. To ascertain energy usage, hardware suitable for the Etchash hash algorithm, which is central to ETC's PoW, is initially identified and pre-selected. A crucial step involves establishing a current profitability threshold for mining operations, derived from an analysis of the revenue opportunities and operational costs associated with mining. Only hardware that surpasses this profitability benchmark is factored into the network's energy consumption calculations. The overall energy consumption is then determined by integrating several key data points: the distribution of eligible mining hardware across the network, the operational efficiency levels of this hardware, and on-chain intelligence pertaining to miners' potential earnings. The methodology also accounts for any significant instances of merge mining, where applicable. For a comprehensive scope, the Functionally Fungible Group Digital Token Identifier (FFG DTI) is utilized, when available, to identify all relevant implementations of the asset, with mappings updated regularly based on data from the Digital Token Identifier Foundation. The information regarding the specific hardware utilized and the total number of network participants relies on informed assumptions, which are diligently validated using empirical data whenever possible. A core assumption underpinning these calculations is that participants largely operate with economic rationality. Furthermore, adhering to a precautionary principle, conservative estimations are employed when uncertainties arise, typically resulting in higher estimates for potential adverse environmental impacts.

Ethereum Classic is present on the following networks: Ethereum Classic.

To accurately assess the proportion of renewable energy utilized by the Ethereum Classic network, a detailed methodological framework is employed, focusing on the geographical distribution of its operational nodes. The initial step involves identifying the physical locations of these nodes through a combination of publicly available information sites, as well as proprietary and open-source crawlers. This meticulous process aims to pinpoint where the computational work securing the network is physically performed. In situations where precise geographical data for nodes is insufficient or unavailable, the methodology strategically leverages "reference networks." These are chosen based on their comparability to Ethereum Classic in terms of incentive structures and core consensus mechanisms, allowing for an informed estimation of energy sourcing in data-sparse regions. Once geographical information is gathered or inferred, it is then cross-referenced and integrated with extensive public datasets provided by Our World in Data. This rich data source offers comprehensive statistics on global energy production and mixes. The ultimate output, energy intensity, is quantified as the marginal energy cost incurred for processing one additional transaction on the network. This provides a granular measure of the energy footprint per unit of network activity. The data from Our World in Data, essential for this analysis, is primarily sourced from reputable institutions like Ember and the Energy Institute, with their "Statistical Review of World Energy" from 2024 and Ember's 2025 data being key components. Specifically, the "Share of electricity generated by renewables – Ember and Energy Institute" dataset is critical for determining renewable energy proportions. This dataset, along with its underlying "Yearly Electricity Data Europe" and "Yearly Electricity Data" from Ember, and the original data from Energy Institute, is available for public access and retrieval from Our World in Data.

Ethereum Classic is present on the following networks: Ethereum Classic.

The methodology for determining the Greenhouse Gas (GHG) Emissions associated with the Ethereum Classic network follows a structured approach, largely mirroring the process for energy consumption analysis by focusing on geographical data. The foundational step involves identifying the physical locations of the network's operational nodes. This is achieved through a combination of public information sources, custom-developed internal crawlers, and various open-source crawling tools. The objective is to establish a precise geographical footprint of the computational infrastructure supporting the blockchain. In scenarios where direct geographical information for the nodes proves to be scarce or entirely absent, the methodology wisely employs reference networks. These alternative networks are selected based on their demonstrable similarities to Ethereum Classic regarding their incentive structures and, crucially, their consensus mechanisms, enabling reasonable estimations of emission sources. This collected or inferred geo-information is then meticulously integrated with publicly accessible datasets from Our World in Data. This robust resource provides extensive global data on carbon intensity, allowing for the calculation of emissions based on the local energy mix at each identified node location. The primary metric derived from this analysis is GHG intensity, which is expressed as the marginal emission generated per additional transaction processed on the network. This metric offers a granular perspective on the carbon footprint associated with incremental network activity. The crucial data from Our World in Data, which underpins these calculations, draws from authoritative sources such as Ember (2025) and the Energy Institute's "Statistical Review of World Energy" (2024), with substantial processing by Our World in Data. Specifically, the "Carbon intensity of electricity generation – Ember and Energy Institute" dataset is instrumental for this purpose. This dataset, comprising "Yearly Electricity Data Europe" and "Yearly Electricity Data" from Ember, and original data from the Energy Institute, is openly available and can be accessed via Our World in Data. The data is licensed under CC BY 4.0.