Why is blockchain so wasteful?

Bitcoin Mining

I have a new post up on the Deloitte blog, coauthored with Robert Hillard.

As we point out in the post:

Bitcoin Miners are being paid somewhere between US $7-$9 to process each Bitcoin transaction.

To do this they’re consuming roughly 157% of a US household’s daily electricity usage per transaction. Those numbers don’t suggest a sustainable future for Bitcoin. They suggest an environmental disaster. And this is by design. So why is Bitcoin so wasteful?

The root of the problem is that in a permissionless and anonymous environment — where anyone can mine — you need to pay the miners, otherwise few will mine. We also know that miners will invest up to the margin (which looks to be around 20% for Bitcoin) to obtain this reward.

You can structure the mining algorithm to favour CAPEX or OPEX, though favouring OPEX is preferred, as it reduces the tendency to centralise. You can also play with where the resources are consumed, either direct in the mining process as with Proof of Work, or more indirectly via Proof of Stake. However, you cannot escape the fact that ultimately Bitcoin works because it consumes real world resources.

This leaves you trapped between two conflicting goals:

  • make the mining pool as large as possible to increase the security of the ledger
  • make the mining pool as small as possible to make the ledger more efficient

The only lever you have to pull is the size of the reward: either via seigniorage, or transaction fees.

Again, as we conclude in the post:

Bitcoin is wasteful as it must be wasteful to work. It isn’t actually waste, it’s really just the cost of securing Bitcoin’s ledger. It is, however, a rather high cost when compared to a more conventional, centralised solution.

Image: Mirko Tobias Schäfer

Posted under: Business-Technology

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