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Network to Undergo Biggest Difficulty Adjustment Ever; BMC Says 67.6% of North American Bitcoin Mining Is Sustainable

But how much do people trust the Council’s methodology?

July 2, 2021

But how much do people trust the Council’s methodology?

This episode is sponsored by NYDIG.

Today on “The Breakdown,” NLW looks at the latest in the highly dynamic, fast-evolving world of bitcoin mining, including:

  • China’s mining ban and the “Great Western Hashrate Migration”
  • Bitcoin’s built-in hashrate fluctuation mitigation, the “difficulty adjustment”
  • The Bitcoin Mining Council’s newest sustainable mining figures

China’s expansive mining ban, including regions with hydroelectric power, forced China-based miners to liquidate some of their crypto in preparation for a move elsewhere. Where will hashrate move next? Will miners join U.S. crypto-friendly jurisdictions like Texas and Kentucky, or will they stay close to home in bordering countries like Kazakhstan and Russia?

The ban induced a massive reduction of hash power on the network. Luckily, Satoshi prepared for such a circumstance and built in a concept of “difficulty adjustment” into Bitcoin’s protocols, which allows for fluctuation in the composition of miners. The adjustment expected to be made tonight will be the highest adjustment ever made on the network.

Lastly, NLW addresses a report released by the Bitcoin Mining Council on sustainable energy disclosures. This report’s feature number, 56% of mining electricity mix is sustainable in Q2 2021, has some groups excited while others remain skeptical of the validity of the report. As NLW argues, “Some data is better than no data.”

Image credit: Iaremenko/iStock/Getty Images Plus, modified by CoinDesk


What's going on guys? It is Friday, July 2, and today we are discussing mining. It's a brave new world out there and things are happening fast. Here's a recap in case you spent the last month, I don't know hiking the Camino de Santiago or something without an internet connection. Towards the middle end of May, the Vice Premier of China started talking about a bitcoin mining ban. The Twitterati initially rolled their eyes at yet another "China Bans Crypto" story, but, interestingly, China based miners did not; they started springing into action almost immediately, including liquidating some amount of their crypto to be able to act more nimbly. Over the following month, we saw numerous state level implementations of a Bitcoin ban, including in a province that mines primarily with hydroelectric power. At first, there had been questions about whether it would be solely coal-powered mining targeted by this ban. But, it turns out that no, it was mining in general. There have been a ton of discussions about motivations. Some have argued it's about ESG concerns in green goals. Others have said it's about China turning their focus from attacking FinTech, to attacking crypto in order to clear any competition for their digital currency. Still, others have speculated that it's about fears of social destabilization that come with crypto, while still others say it's about cracking down on local corruption. Whatever combination of these things and others is correct, it has happened. 

As you heard on "Long Reads Sunday" last week, the broad sense is that the "Great Western Hashrate Migration" is real. That being said, there is still a ton up in the air. What portion of miners are going to move their business to the U.S., to newly friendly jurisdictions like Texas and Kentucky, how many are going to move to more convenient countries bordering China like Kazakhstan or Russia. But as that happens in the short term, a huge amount of hash power has left the network as much as about 50%. 

Luckily, there is the difficulty adjustment, one of bitcoin's most elegant and least appreciated features. So what is difficulty adjustment? In short, Satoshi knew the network would need to be resilient to exogenous shocks in the composition of miners. The difficulty adjustment is a process by which the network can automatically make winning blocks easier or more difficult based on how much competition there is among miners. When lots and lots of miners are using lots and lots of power to try to mined blocks. The difficulty gets harder. When miners leave the network, the difficulty adjusts down. The difficulty matters because it can determine, based on both the cost of capital expenditures as well as the cost of local electricity, whether a certain mining rig is actually profitable to mine with or not. When the difficulty is high, older machines can be useless, but can become profitable again, when the difficulty decreases. This process happens every two weeks, well, every 2,016 blocks, which at 10 minutes per block is roughly two weeks. 

Today, we're expecting to see a roughly 27% drop in the difficulty, which will make it the biggest difficulty adjustment ever, by a lot as well. It's 50% more of an adjustment than the previous biggest adjustment which was 18%, all the way back in 2011. It's also the third straight difficulty decline, which hasn't happened since December 2018. The important thing about all this is, it will go off without a hitch, incentivizing more hash power to come back online, motivated purely by it being more economical for them to do so. Difficulty adjustment is one of the most truly insanely visionary parts of the design of this entire economic system. It is such a simple, clean, perfect use of market incentives to keep everything running smoothly. It is resilience incarnate.

It wasn't the only interesting thing that happened with mining over the last 24 hours or so, however. Again, for those who were off on the Appalachian Trail or whatever, around the time that all this China stuff was going down, Michael Saylor convened a group of the largest North American mining interests. He invited Elon Musk to the first meeting and they discussed, well, a ton of things, but the one conclusion or shared commitment that they came away with, was about standard disclosures for energy usage. The idea was that whatever those numbers actually showed, at least they would be canonical, rather than random estimates from random studies that critics could cherry pick to make things look worse than they were. 

This group called themselves the Bitcoin Mining Council and there was a fair bit of controversy around it. Was it too much like the closed door group of corporates from the New York agreement? Why were they soliciting Elon? Etc, etc. Still, net net most Bitcoiners have given the Bitcoin Mining Council the benefit of the doubt, and one interesting little nugget of the story as well, was that at some point over the last couple of weeks, in response to a tweet saying that he had completely abandoned bitcoin, Elon said no, he hadn't, and in fact, set an unofficial target of renewables composition at 50%. Once 50% of bitcoin was mined by renewables, and that was trending to improve, Tesla would begin accepting Bitcoin again. Now, I've talked about this on shows before and I don't want to dwell on it, but I do think there is a certain logic and setting a target that advocates, particularly those on the regulatory side, can rally around. 

Either way, the Bitcoin mining council popped up yesterday with an interesting document. Michael Saylor tweeted, "Based on the Bitcoin Mining Council survey of the network, mining electricity mix increased to 56% sustainable in Q2 202, making Bitcoin one of the cleanest industries in the world." Now, that's a pretty spicy headline, especially in the context of that 50% target from Elon. But, what's the fine print? What are the details? Well, first the composition of the group, the BMC now lists 23 members who represent 32% of global hash power. Their presentation argues that among those members, 67.6% of mining is sustainable sources. The 56% number represents the whole world and is an estimate, they argue that sustainable mining grew significantly between Q1 and Q2 from 36.8% to 56%, a 52.2% jump overall. 

Now, when they say sustainable electricity, what do they mean? Well, they define it as electricity that's generated by hydro, wind, solar, nuclear, geothermal and carbon based generation with net carbon credits. They say it's based on the principles brought forward by the EIA's "Net Zero by 2050" report. Second, on how they got the global data, quote, "The BMC surveyed Bitcoin miners around the world, asking three questions: one, how much electricity does your total fleet consumed today; two, what is the total percent of sustainable electricity within your fleet's power generation mix today; three, what is the total aggregate hashrate of your fleet today?" 

One nugget I want to pull, purely from a marketing and advocacy perspective, is a new line that they're pitching. The slide that sets up the rest of the deck says: "Bitcoin mining uses a negligible amount of energy, is rapidly becoming more efficient and is powered by a higher mix of sustainable energy than any major country or industry." That higher mix of sustainable energy is obviously a narrative upending and it's something that we can plausibly argue, precisely because of the transparency of the network. So, everyone just accepted these numbers as canonical now, right? Well, this is Bitcoin. Of course not. 

Larry Cermak, who was on the show a couple weeks ago, responded to Saylor's tweet saying: "This is really laughable. No methodology discussed, very dubious result, and super small sample of like 5% of the total hashrate. No one knows what the energy mix will look like until the hashrate from China relocates and a new proper study is conducted. Why do people trust this?" That was tweeted mid conference call, so a bit more was revealed, but Larry was still uncomfortable with how up in the air things are right now. Quote, "How can any conclusions be made from the survey if more than 50% of hashrate went offline and is relocating at the moment, which can easily take months." 

Zack Voell, who used to be at CoinDesk, and who is now working with Compass Mining agreed that there's too much up in the air for this to feel at all representative. Although Amanda Fabiano, who heads up Galaxy Digital's mining efforts, and who is on the council replied: "At what point would it be okay to pull, Zack? The network is literally always growing and changing. This is a snapshot of time, next quarter will be another snapshot in time." For my part, I don't think those concerns are illegitimate. This is a moment of seismic upheaval for the entire network, perhaps the most significant in the history of bitcoin mining, at least since ASICs became available. However, I think I tend to come down on the side of Nic Carter. And so, we're going to read a few tweets from his thread about all of this.

He says: "The point is, we had no bottom up data. Now we have bottom up data for 1/3 of the network. That's great. This whole exercise is an attempt to put together a patchwork of disparate sources. Obviously, more data is better than none. Still a lot of guesswork: is the headline figure of 56%, sustainable accurate? It relies on a bunch of assumptions on the rest of the world, I would encourage BMC to publish in full their additional methodological assumptions for out-of-sample miners, otherwise, we can't evaluate the combined figure. Should we wait until that 50% of lost hashrate comes back online before trying to evaluate Bitcoin CO2 outlay? No, that could mean waiting for over a year. What matters is hashrate today and much of that hashrate will be going west. So, BMC's sample likely to be decently predictive. Is this a slam dunk? Not yet. BMC is still growing and we'll have more hashrate in Q3, also coming soon: new CBECI data, pool based with less risk of sample bias. Together, these two data sets will give us unparalleled view into the energy mix. Many will attack BMC, especially over extrapolation to 56% sustainable, but even if you disagree with out of sample assumptions, in sample data, still useful, huge share of North American mining represented and ultimately, we're dealing with North American press and North American investors. North American mining is clean. Be critical, I am too, see the thread. But there's genuinely useful new data here that you can use as a model input, even if you disagree with out of sample assumptions. Hell, you can make a model that stipulates that all rest of world mining is coal based, go crazy. At this point, it's clear that the BMC has managed to amass a big coalition of miners in a short period of time, 1/3 of all hashrate, quite significant. Q3 will be bigger. Write them off at your own risk, these disclosures will move the needle. So many of the issues with mining coverage stemmed from academics and pundits given free rein to publish garbage, with no one to push back. Now, bitcoin miners are furnishing their own data, this stuff matters."

I just tend to agree that having some data is almost infinitely preferable to no data. And frankly, whatever one thinks if you weren't sure of how serious the Bitcoin Mining Council was going to be in terms of becoming an advocacy group and changing the narrative around bitcoin mining, I think that answer is now clear. Anyways guys, I hope you're headed to a great holiday weekend. I appreciate you listening and until tomorrow, be safe and take care of each other. Peace!