Blockchains sure need a lot of power

With the increasing contribution of Renewable Energy Sources towards electricity grids, and the accompanying drive towards more flexibility in the grid, blockchains get thrown around as a potential solution, as well as a means to disintermediate traditional utilities. What’s often forgotten in that discussion is that blockchains are quite energy intensive on their own. As writes Christopher Malmo for Vice Motherboard:

In 2015, I wrote that bitcoin had a big sustainability problem. Back then, each bitcoin transaction represented roughly enough electricity to power 1.57 American households for a day— approximately 5,000 times more energy-intensive than a credit card transaction. Since it's been two years, it's time for an update.

A new index has recently modeled potential energy costs per transaction as high as 94 kWh, or enough electricity to power 3.17 households for a day. To put it another way, that's almost enough energy to fully charge the battery of a Tesla Model S P100D, the world's quickest production car, and drive it over 300 miles.

He’s writing about Bitcoin, and most electricity trading on the blockchain experiments are going with Ethereum. But Ethereum follows the same fundamental model: a blockchain in which transactions are secured by a proof-of-work system that involves hashing. It’s reasonable to assume then that the energy consumption footprint would look similar.

Ethereum wants to move to Proof-of-Stake, which would drastically reduce the power consumption overhead the protocol incurs, but introduces different problems, possibly even this year.