[Paper Review] A Cradle-to-Gate Life Cycle Analysis of Bitcoin Mining Equipment Using Sphera LCA and ecoinvent Databases

Ludmila Courtillat--Piazza, Thibault Pirson+2 more|arXiv (Cornell University)|Jan 31, 2024

Recycling and Waste Management TechniquesEnvironmental Science3 citations

TL;DR

This study conducts a cradle-to-gate life cycle assessment (LCA) of Bitcoin ASIC mining hardware using Sphera LCA and ecoinvent databases, revealing that the application-specific integrated circuit (ASIC) is the dominant source of environmental impacts across all categories—especially for resource scarcity and ecotoxicity. Despite lower global warming potential compared to use-phase emissions in high-carbon regions, production impacts can account for up to 80% of total life cycle impacts when mining uses low-carbon electricity, highlighting the critical need to include manufacturing in environmental assessments of crypto-mining systems.

ABSTRACT

Bitcoin mining is regularly pointed out for its massive energy consumption and associated greenhouse gas emissions, hence contributing significantly to climate change. However, most studies ignore the environmental impacts of producing mining equipment, which is problematic given the short lifespan of such highly specific hardware. In this study, we perform a cradle-to-gate life cycle assessment (LCA) of dedicated Bitcoin mining equipment, considering their specific architecture. Our results show that the application-specific integrated circuit designed for Bitcoin mining is the main contributor to production-related impacts. This observation applies to most impact categories, including the global warming potential. In addition, this finding stresses out the necessity to carefully consider the specificity of the hardware. By comparing these results with several usage scenarios, we also demonstrate that the impacts of producing this type of equipment can be significant (up to 80% of the total life cycle impacts), depending on the sources of electricity supply for the use phase. Therefore, we highlight the need to consider the production phase when assessing the environmental impacts of Bitcoin mining hardware. To test the validity of our results, we use the Sphera LCA and ecoinvent databases for the background modeling of our system. Surprisingly, it leads to results with variations of up to 4 orders of magnitude for toxicity-related indicators, despite using the same foreground modeling. This database mismatch phenomenon, already identified in previous studies, calls for better understanding, consideration and discussion of environmental impacts in the field of electronics, going well beyond climate change indicators.

Motivation & Objective

• To assess the environmental impacts of producing Bitcoin mining hardware, particularly ASIC miners, which are often overlooked in lifecycle analyses.
• To investigate how the production phase contributes to overall environmental burdens, especially in comparison to energy use during operation.
• To evaluate the influence of electricity source and equipment lifespan on the relative significance of production impacts.
• To identify and discuss discrepancies between two major LCA databases—Sphera LCA and ecoinvent—particularly for toxicity-related indicators.
• To provide a data-driven basis for future assessments of crypto-mining systems that include both production and operational phases.

Proposed method

• Conducted a cradle-to-gate life cycle assessment (LCA) of the Antminer S9 ASIC miner using the ReCiPe 2016 characterization method.
• Employed Sphera LCA (GaBi) and ecoinvent 3.8 databases for background inventory modeling, enabling cross-database comparison.
• Modeled the full production chain of the ASIC miner, including material extraction, component manufacturing, and system integration.
• Performed sensitivity analysis across multiple electricity sources and equipment lifespans to assess their impact on total life cycle burdens.
• Adapted the LCA model to the newer Antminer S19 Pro to compare impacts across different generations of ASIC miners.
• Identified and quantified discrepancies in toxicity-related impact categories between Sphera LCA and ecoinvent databases, despite identical foreground modeling.

Experimental results

Research questions

• RQ1 What is the relative contribution of the production phase to the total environmental impact of Bitcoin ASIC mining hardware, particularly across different impact categories?
• RQ2 How do variations in electricity source and equipment lifespan affect the significance of production-related impacts in the overall life cycle?
• RQ3 To what extent do discrepancies between Sphera LCA and ecoinvent databases affect the assessment of toxicity-related environmental impacts in electronic hardware?
• RQ4 How do the embodied impacts of newer ASIC miners (e.g., Antminer S19 Pro) compare to older models (e.g., Antminer S9) in terms of environmental burden per unit of hashrate?
• RQ5 Under what conditions does the production phase of mining hardware become the dominant contributor to total life cycle impacts, especially when electricity is low-carbon?

Key findings

• The ASIC chip is the primary source of environmental impact across all ReCiPe 2016 impact categories, including global warming potential, resource scarcity, and ecotoxicity.
• Production impacts can account for up to 80% of the total life cycle impacts when mining is powered by low-carbon or renewable electricity, challenging the assumption that use-phase energy dominates environmental burdens.
• Despite identical foreground modeling, the Sphera LCA and ecoinvent databases produced results differing by up to four orders of magnitude for ecotoxicity indicators, indicating significant data inconsistency.
• The environmental impact of producing an Antminer S19 Pro is estimated to be 2 to 2.5 times higher than that of the Antminer S9, suggesting that larger, more powerful miners have significantly higher embodied impacts.
• The study demonstrates that the production phase is not negligible for non-climate impact categories, even when global warming potential is dominated by the use phase.
• The findings underscore the importance of including production impacts in LCA of crypto-mining systems, especially as electricity grids decarbonize and operational emissions decrease.