The Bitcoin mining hash rate had been exponentially increasing on average since the genesis block in 2009, from MH/s, to GH/s, to TH/s, to PH/s, to EH/s, and it reached an all-time record high of 62 EH/s on 26 August 2018. Since this peak was reached, the Bitcoin mining hash rate gradually plateaued and has now decreased. The chart of Bitcoin mining hash rate actually looks quite similar to a peak oil chart except on a much faster time-scale, as can be seen in the comparison between Bitcoin’s hash rate over the course of 2 years from Blockchain.com and North Sea oil production from an article in The Oil Drum: Europe by Euan Mearns. As explained below, the dynamics between peak oil and peak Bitcoin mining are similar, with the key difference that Bitcoin mining is decentralized and oil is not.
Geologist M. King Hubbert is the founder of the peak oil theory, which states that there is a point when the maximum extraction rate of petroleum is reached, after which a terminal decline in production ensues. The peak rate of extraction of Bitcoin of course occurred during the period after the genesis block and before the first block halving, when the block reward was at its maximum of 50 Bitcoins. However, this is not the peak rate of mining profitability, since Bitcoin increased in price by orders of magnitude through the year 2017. The peak rate of Bitcoin mining profits undoubtedly was simultaneous with Bitcoin’s all-time record high of USD 20,000 in December 2017.
The reason the peak hash rate did not coincide with the peak rate of Bitcoin mining profits is because the rally happened so quickly that mining operations were not able to add rigs fast enough, so there was a lag effect. Even for mining operations with large amounts of capital it can take months to obtain the amount of mining equipment that they want, and for other mining operations it took even longer because they had to obtain investors, buy land, build infrastructure, and only then could they install the rigs and begin hashing.
The Bitcoin mining hash rate chart implicitly indicates that 30 EH/s of Bitcoin mining equipment has been taken offline due to lack of profitability, which represents tens of billions of USD of wasted rigs. This suggests that Bitcoin miners were caught by surprise by the decline in Bitcoin’s price from USD 20,000 to less than USD 4,000 as of 4 December 2018.
Coming back to the peak oil comparison, the current Bitcoin mining scene is like a rapid version of peak oil, combined with lack of coordination. Oil mining is a centralized and coordinated activity, where the oil is prospected, land is leased out and then an appropriate number of wells are drilled. With oil mining, companies cannot drill as many wells as they want, or drill wells on someone else’s lease, since this is all closely controlled by contractual agreements. Bitcoin mining is decentralized, and no one has a lease or contract to only mine with a certain amount of hash rate. Anyone in the world can run as much Bitcoin mining rigs as they can afford. The effect is that people all around the world are sticking their straws into the Bitcoin mining network all at the same time, and they sucked it dry. Essentially, so many people started up new mining operations at once without coordination, that the Bitcoin mining hash rate went way past its equilibrium, which hurt everyone involved. This is akin to if oil drilling was a decentralized process, and anyone who wanted to drill for oil could drill in the same field. The oil field would be sucked dry really quick, and then most of the drills would be shut down due to lack of profits.
There is hope for Bitcoin miners however. The price of Bitcoin simply has to rally, and all of the disenfranchised miners could restart their rigs, and then it would be back to the races and new rigs could begin being added. However, due to the decentralization of Bitcoin mining, the network hash rate will likely periodically rise past its equilibrium point, leading to catastrophic conditions for miners like we are experiencing today at points in the future. The only thing that could prevent the scenario we are experiencing today is a Bitcoin rally that lasts forever, which is obviously not possible.
James McAvity tweeted that Bitcoin mining is still profitable in the current environment, and does some simple linear calculations to prove this point. He also argues that miners are forced to keep mining due to business agreements, choose to HODL in expectation of a rally, and continue mining in expectation of a downward difficulty adjustment as other miners go offline.
Some of what McAvity says is true, but the reality is that Bitcoin mining is a highly non-linear system, and calculating the support level for mining is somewhat pointless, since it is different for every miner. Bitcoin mining profitability depends on Bitcoin’s price, the Bitcoin network hash rate which is directly correlated to mining difficulty, and the technological efficiency of Bitcoin mining rigs. These 3 factors are related in a non-linear and ever-changing way.
Instead of trudging away at trying to develop a set of equations that determine mining hash rate behavior, one could simply look at the Bitcoin mining hash rate chart at the beginning of this article to understand what is going on. Bitcoin mining profitability is different for each individual miner, and the hash rate has trended downwards as individual miners have made the decision to shut down rigs. Clearly there was a fundamental mining profitability support level in the USD 6,000-7,000 range, since that is where Bitcoin’s price was when mining peaked and plateaued. There are clearly numerous miners who became unprofitable on the descent from that level to less than USD 4,000 today, and now approximately 50% of the Bitcoin mining equipment that exists cannot profitably mine. The decrease in Bitcoin’s mining difficulty of 15% on 3 December 2018 could help bring some of those miners back online, at least if the price stays at current levels around USD 4,000, but this will not change the overall trend.
When it comes down to it, Bitcoin’s price is in control of Bitcoin mining profitability, and if the price goes up we could see a reversal of the hash rate downtrend and eventually a 2nd peak in Bitcoin’s network hash rate. However, if price continues to go down, the Bitcoin mining hash rate chart will follow a similar pattern to peak oil charts. The reality will likely be a combination of both. Bitcoin bear markets tend to last years, and get more severe, but eventually the rally comes and then Bitcoin exceeds its all-time record high. This would lead to a steady decrease in Bitcoin’s mining hash rate like the peak oil chart, followed by a rapid re-engagement of old mining rigs that have been taken offline, and then the addition of new generation Bitcoin mining rigs once the equilibrium hash rate exceeds 60 EH/s.