Bitcoin's Water Footprint Soars to 16,000 Litres per Transaction
A recent study published in the Cell Press journal Cell Reports Sustainability found that the average water footprint of a Bitcoin transaction in 2021 was approximately 16,000 litres. This includes both direct and indirect water use, with the majority coming from electricity generation.
According to the study, the water footprint is roughly 6.2 million times larger than that of a single credit-card swipe, which has a water footprint of around 2.6 millilitres. The researchers used data on where Bitcoin's computing power is located and regional water-intensity figures to estimate the total water use.
The study found that Kazakhstan accounted for 63% of Bitcoin's 2021 water footprint, despite hosting only 14% of its computing power. The average water intensity across Bitcoin's power mix rose from 8.63 litres per kilowatt-hour in 2020 to 15.0 litres per kilowatt-hour in 2021.
Some experts have questioned the methodology used in the study, arguing that it overestimates the water footprint of Bitcoin transactions by counting indirect water use that would occur regardless of Bitcoin mining. Others have pointed out that the water footprint is heavily influenced by decisions about where mining farms are located and what power sources they draw on.