Bitcoin's carbon footprint is out of control.
An analysis of the carbon footprint of the Bitcoin network using the Bitcarbon Method.
by Guy Lane last update Friday, 19 December, 2013.
My name is Guy Lane.
I am a professional carbon auditor and sustainability advisor and I have been running the numbers on Bitcoin.
Bitcoin is a widely distributed network with no single entity paying the powerbills and, as such, the electricity demand can't be modeled using normal techniques.
So, I have developed a simple method for calculating the electricity consumption of the Bitcoin network - based on the exchange rate of Bitcoins - and then applied a standard methodology to determine the carbon footprint.
I call this the Bitcarbon Method.
Bitcarbon Method is not an absolute truth; instead it is a simple and rational model that seeks to highlight the scale of the Bitcoin carbon footprint.
If my model is right, then Bitcoin represents a new danger to planet Earth (as if we really needed another one).
I share this insight in order to create discussion and I invite all readers to offer critical analysis of these findings.
For those who have not heard of Bitcoin, here is a brief introduction.
Bitcoin is an online currency that hit the news in December 2013 for its rapid appreciation: Bitcoins worth US$14 in January were trading at around US$1,000.
Bitcoin is making people rich, offering a way of trading without feeding the Vampire Squids of Wall Street and other non-mutual bankers, and giving people plenty of entertainment, trying to figure out how it actually works.
Bitcoins are referred to as a crypto-currency because key structural elements of the system are based on cryptography, the science of secure communications.
The individual Bitcoins in the system are 'mined' by thousands of computers crunching complicated algorithms called 'hashes'.
These cryptographic algorithms are at the heart of the Bitcoin mechanism and are widely lauded for their technical brilliance.
Bitcoins were specifically designed to gobble up increasingly vast amounts of computational effort, resulting in spiralling electricity consumption.
And the ever-growing electricity bills on the Bitcoin network is a systemic design element that optimises the Bitcoin money supply.
At time of writing (Dec, 2013), the computational grunt of the Bitcoin mining network is over seven million gigahashes per second - that is seven million, billion hashes every second.
According to Forbes, global bitcoin computing power is 256 times faster than the top 500 supercomputers, combined!
All this computing power comes at a cost: a massive power bill and equally huge carbon footprint on an overheating planet already beleaguered by 200 years of industrial activity based on coal and oil.
To make matters worse, Bitcoin mining is projected to go on until about 2140 when the last Bitcoin - the 21 millionth - will be mined.
Now, if Bitcoin transactions were restricted to the occasional online shopping spree for porn, weed and pirate movies (as Bitcoin is infamous for), the Bitcoin network’s carbon footprint would probably be too trivial to mention.
However, with Bitcoin trading at up to $1,200 apiece and the total transactional volume up to $500 million a day, the Bitcoin genie is well and truly out of the bottle.
Bitcoin was launched in January, 2009 just as the the GFC was starting to tear the US economy apart; however, 2013 was definitely the year that Bitcoin matured (not bad for a four year old).
Indeed, in 2013, US Congressman, Ron Paul, speculated that Bitcoin could be the currency of last resort if the US dollar collapses.
Also in 2013, Bitcoin attracted the attention of Wall Street and plans are probably already afoot to commandeer the formerly democratic currency in order to manipulate it, hyper-inflate it, short it, crash it, pick it up for next to nothing then walk away with billions.
And this invites an intersting question - how much could bitcoin be worth?
While we are speculating on Bitcoin's future price, imagine Bitcoin worth $1 million apiece; and while you are at it, consider each of Bitcoin's 100 million sub-units being worth a dollar each, valuing a single Bitcoin at $100 million.
However, there is no point in speculating this far because - according to the Bitcarbon Method - if Bitcoin were worth even $10 million, the carbon footprint of the Bitcoin miners would be nearly triple the present global footprint of 30 gigatons per annum.
And this would be catastrophic to Earth and its people.
As such Bitcoin threatens to excacerbate The Great Disruption and accelerate the existing trends that are already breaking the arctic, baking Earth's living systems out of existence, turning the ocean into acid and forcing Earth to lose homestasis.
Bitcoin is Climate Code Red, writ large and this begs the question, how did we get into such a mess?
The trouble stems from the fact that the Trekkies who invented Bitcoin failed to account for that fact that we humans live inside the biosphere of planet Earth and not an orbiting space-station powered by fusion reactors.
And it has taken until April, 2013 for the news to get out.
In April, 2013, Bloomberg reported that the energy demand of the Bitcoin network was a real world environmental disaster and stated that their information came from an online resource called blockchain.info.
A week later, Cleantechnica checked on the same data and found that the electricity consumption of the Bitcoin network had climbed from 982 to 1,046 megawatt hours per day (MWh/day).
The data showed that the Bitcoin network electricity consumption increasing by 64 MWh/day - in a week.
To put this into perspective, Bitcoin's electricity demand increased by the equivalent of about 2,600 homes - in a week.
Interestingly, on about 20 December, 2013 - a week after Bitcarbon started to communicate the carbon footprint calculations to the media - Blockchain removed its electricity calculation from its stats website.
Bitcarbon has investigated the methodology underpinning the blockchain.info electricity data and found it to be wanting (it was actually too high - see below for comparison).
So Bitcarbon has developed a new method that addresses some of the weaknesses and specifically seeks to quantify the carbon footprint of the Bitcoin network.
This model is referred to as the Bitcarbon Method.
The Bitcarbon Method considers only the energy used in the process of mining Bitcoin and excludes the other energy costs associated with massive volumes of data transfer, such as the 9GB to download (in Dec 2013) the blockchain for new users.
It is intended that the Bitcarbon Method will be continually improved through research into Bitcoin miners' energy consumption, their location and the carbon intensity of the electrical networks they use.
This first release of the model (Version 1.0 - Dec, 2013) is described below.
The Bitcarbon Method(v1.0) assumes that the amount of money a Bitcoin miner will spend on electricity is proportionate to the exchange value of the bitcoin and as bitcoin becomes more valuable, more electricity will be consumed across the Bitcoin network.
In order to create a numeric model of this phenomena, an assumption has been made that miners will spend up to 90% of the value of Bitcoin on electricity.
There are obviously other factors to be considered in the equation such as the cost of establishing the mining rigs and the small fees that come from mining.
Accomodating the first of these considerations would lead to a reduced carbon footprint of mining Bitcoin and incorporating the latter would raise the footprint a little.
Acknowledging these shortcomings, the Bitcarbon Method Ver 1.0 goes on to assume that half of the mining effort takes place in the USA and half in China.
In reality, Bitcoin mining can take place anywhere on the planet where there is a mains power outlet.
Using the USA/China assumption allows us to develop a globalised figure for the carbon intensity of mains power and the price per unit of electricity.
According to the International Energy Agency, the carbon intensity of mains power in the USA and China is 0.52 and 0.77 kg CO2 per kWh, respectively (0.52 and 0.77 tonnes CO2 per MWh).
Averaged, this means that every Megawatt hour of electricity used for mining Bitcoin puts 0.65 tons CO2 into the atmosphere (more in China, less in USA).
If you model these numbers against the cost of mains power - estimated at $0.12 and $0.08 per kWh for USA and China respectively - you get an average carbon intensity 6.98 kg CO2 per $ spent on electricity used for mining Bitcoin.
Perhaps not unsurprisingly, these figures indicate that the carbon footprint of a 'Chinese Bitcoin' is more than double that of an 'American Bitcoin'.
This is becuase Chinese electricity is dirtier and cheaper than American electricity.
With these numbers in hand, we can consider the projected carbon footprint of the Bitcoin network assuming varying exchange rates for the Bitcoins.
Keep in mind that the humans presently put about 30 billion tonnes (30 gigtonnes) per annum of CO2 into the atmsophere mostly through burning fossil fuels to make electricity.
Some would say that CO2 is just plant food and the more the merrier. Others would suggest that too much CO2 in the atmosphere is not a good thing. This argument is completely seperate to the question of much of CO2 is produced by the Bitcoin network.
To put these numbers into perspective, I have modeled the carbon footprint of Bitcoin using two other methodologies.
With electricity costs being a major cost in mining Bitcoin, there are ongoing efforts to develop new Bitcoin mining technology that is super energy efficient and thereby decreases the number of watts/gigahash.
How will the adoption of new technology affect the carbon footprint of the Bitcoin miners?
Initially, the adoption of these new rigs will make the network on average less carbon intensive.
However, due to the systemic design of the Bitcoin system, the adoption of new technology will not reduce the carbon footprint of the Bitcoin network.
This is because, as mining becomes cheaper, it will become more profitable, more people will partake in Bitcoin mining and the difficulty will be raised to slow down the mining process.
With a higher difficulty, more effort (electricity) will be exerted to generate bitcoin and more CO2 will be emitted.
This phenomena is show in the diagram below.
According to the wiki entry on bitcoin.it, "The cost to mine bitcoins is based on how much they are worth. If bitcoins go up in value, more people will mine (because mining is profitable), thus difficulty will go up, thus the cost of mining will go up. The inverse happens if bitcoins go down in value. These effects balance out to cause mining to always cost an amount proportional to the value of bitcoins it produces."
A question then arises: will Bitcoin ever reach these dizzing heights of carbon intensity and triple the planets carbon footprint.
Probably not, for a number of reasons.
First, there are already problems with supplying sufficient energy generating capacity to electricity networks around the world, particularly as there are other competing priorities for the electrons such as powering hospitals, running factories and homes, and keeping beer cold.
Second, the world's Government's would never allow the carbon footprint of commerce to spiral out of control. Hmmm, actually, I am not so sure about that.
Third, the public would never put up with its favourite currency destroying the planet.
Instead, maybe the public would demand that the Bitcoin Foundation tweak the algorithms to make the currency ecologically sustainable - is this actually possible?
Or maybe the Bitcoin community will choose take responsibility for their personal share of the Bitcoin carbon footprint by carbon offsetting.
Or maybe they will shift their allegiances to a cryptocurrency that is ecologically sustainable, assuming such a thing is possible.
How will it all pan-out is unclear.
However, it is looking increasingly likely that, for the foreseeable future, Bitcoin is going to give the atmosphere a severe hiding.
And that is bad news for everyone, even the Bitcoin miners (assuming that they don't actually live in an orbiting spacestation, that is).
What we need on Earth is a class of humans who can design complex business systems that operate within the natural constraints of our global ecosystem and that are consistent with the aspiration for a Long Future.
That way, the next great idea to explode onto the world stage won't end up being potentially one of the last.
Failing that, we are going to need Zem, the trillionaire spaceman to bail us out.