A single bitcoin transaction generates the same amount of e-waste as throwing two iPhones into the trash, according to a new analysis by economists at the Dutch central bank and MIT.
While bitcoin’s carbon footprint is well-studied, less attention has been paid to the large loss of computing hardware incentivizing cryptocurrency. Specialized computer chips called ASICs are sold for no other purpose than to run the algorithms that secure the bitcoin network, a process called mining that rewards those who participate with bitcoin payments. But because only the newest chips are energy efficient enough to mine profitably, effective miners must constantly replace their ASICs with newer and more powerful ones.
“The lifespan of bitcoin mining devices remains limited to just 1.29 years,” write researchers Alex de Vries and Christian Still in the article, The Growing Bitcoin E-waste Problem, published in Resources, Conservation and Recycling magazine.
“As a result, we estimate that the entire bitcoin network currently runs 30.7 metric kilotons of equipment per year. This number is comparable to the amount of small waste of computer and telecommunications equipment produced by a country like the Netherlands. “
In 2020, the bitcoin network processed 112.5 million transactions (compared to 539 billion processed by traditional payment service providers in 2019), according to economists, meaning that each individual transaction “equals to less 272 g of electronic waste “. That’s the weight of two iPhone 12 minis.
The reason e-waste is a problem for cryptocurrency is that, unlike most computer hardware, ASICs have no alternative use beyond bitcoin mining, and if they cannot be used to mine bitcoins profitably, they serve no future purpose. In theory, it is possible for these devices to regain the ability to operate profitably at a later point in time in the event that bitcoin prices spike suddenly and mining revenue spikes, the authors note.
“However, there are several factors that generally prevent a substantial extension of the useful life of mining devices,” they add. Mining hardware storage costs money, and the longer it is stored, the less likely it is to be profitable.
The authors also warn that the e-waste problem will likely grow further if the price of bitcoin continues to rise, as it will incentivize further investment and replacement of ASIC hardware.
If the community were to try to reduce its e-waste problem, the document concludes, it would need to replace the bitcoin mining process “in its entirety with a more sustainable alternative,” and the document suggests “proof of stake,” a replacement experimental test. Ethereum, a successor to bitcoin, announced plans in May to move to proof of stake in a few months, although the change has yet to take place.
Other bitcoin alternatives have been less successful in limiting their environmental footprint. Chia, a cryptocurrency that is based on a “test of time and space” algorithm, has been accused of causing a shortage of hard drives and SSDs, a type of storage medium popular in fast computers. “Rather than just wasting electricity, Chia chews on SSDs at a fantastic rate and has also completely ruined the market for large HDs,” said David Gerard, a cryptocurrency expert.