Bitcoin has an electronic-waste problem

Abstract

The surging popularity of bitcoin comes at a huge environmental cost. According to the latest analysis of its sustainability, the electronic currency uses as much energy as a medium-sized country and could generate thousands of metric tons of electronic waste per year (Joule 2019, DOI: 10.1016/j.joule.2019.02.007). Users “mine” new bitcoins with customized computer chips that solve cryptography problems and record their ownership of this cryptocurrency in a shared database called a blockchain. As more bitcoins enter circulation—there are currently about 17.5 million of them—it gets progressively harder to mine new coins, requiring more computing power and, therefore, more energy. Alex de Vries, a blockchain specialist at the accountancy firm PricewaterhouseCoopers in Amsterdam, has calculated that bitcoin mining in 2018 used 40–62 TW∙h of energy and had a carbon footprint of 19 million–30 million metric tons (t) of CO2 emissions. Bitcoin already accounts for at least 20% of the energy consumption