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Dirty bits: the cost of cryptocurrencies

  • Written by  Marco Magrini
  • Published in Energy
Dirty bits: the cost of cryptocurrencies Nickolastock
30 Jan
Cryptocurrencies might be setting the world’s digital economy on fire, but for Marco Magrini, they’re also heating up the physical planet

Among the Digital Revolution myths, there was the dream of a decline in fossil-fuelled energy consumption through a variety of reasons, such as video-calls replacing air travel. In the last 20 years though, the number of air passengers has skyrocketed, and the gigantic stream of data crossing the world at light-speed, mostly powered by gas and coal, is already emitting as much carbon dioxide as civil aviation – two per cent of the total.

For decades, the progress in miniaturisation increased both performance and power efficiency of microprocessors. Now, having approached the minimum physical limit of a few nanometre, a similar progress is mostly obtained with multiple ‘cores’, which make chips faster but also much hungrier. It is estimated that in 2016, data centres worldwide gobbled 416 terawatts per hour, one and half times the United Kingdom’s electricity consumption. It is predicted to double every four years.

Data usage has spread monumentally in geographical, technological and social senses. Bits and bytes have infiltrated almost every aspect of our daily life, and are busy taking over any remaining ones. Billions of connected devices, from garage doors to lights, from cars to medical equipment, are sending data back and forth throughout the planet, continuously. But there is something more. The explosion of artificial intelligence applications implies a substantial increase in data processing and, therefore, in energy consumption. Not only are the number of connected devices and AI-based services expected to double in a handful of years, but we have fresh examples of how the digital realm itself could get greedier and greedier.

Let’s take Bitcoin, the quintessential cryptocurrency. In order to ‘mine’ it in the public ledger called a ‘blockchain’, you need to run painstaking calculations. This is largely being carried out in China, where the energy to power the computers comes from cheap and dirty coal. One company, Bitmain Tech, keeps 25,000 computers running inside eight Inner Mongolian warehouses. The Bitcoin industry’s power use is said to equal that of three million US households. Plus there are at least 32 other cryptocurrencies out there. A few big names, such as Apple and Google, are sourcing clean energy for some of their operations. But it’s not enough. While the world keeps running on fossil fuels, our digital sustainability is in question. 

This was published in the February 2018 edition of Geographical magazine.

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