As Bitcoin has become increasingly mainstream, questions about how it works have naturally arisen among both investors and the general public. One of those questions is about the potential environmental impact of mining, which is the process the blockchain uses to generate new bitcoin and verify transactions.
, May 24, 2021
, 6. min read time
First, a basic fact: Bitcoin mining is an energy-intensive process. There’s no debate about that. As prices climb, new miners are incentivized to participate, which drives up energy usage (at least until the next halving, when the amount of new bitcoin issued will be reduced by half).
But teasing out the actual environmental impacts of that energy use is, like a lot of things, complicated. In this post we’ll look at some of the major concerns that are often raised, and see how much truth there is to them.
According to the best available science, this simply isn’t true. While Bitcoin’s energy consumption is significant, that doesn’t automatically equate to it being a meaningful driver of climate change. To understand why, it helps to know a little about how mining works.
Mining is the process that Bitcoin and some other cryptocurrencies use to generate new coins and verify new transactions. Vast, decentralized networks of computers around the world secure blockchains (the virtual ledgers that document cryptocurrency transactions). In return for contributing their processing power, miners are rewarded with new coins. It’s a virtuous circle: the miners maintain and secure the blockchain, the blockchain awards the coins, and the coins provide an incentive for the miners to maintain the blockchain.
In April, there was a flurry of headlines warning that emissions from Bitcoin mining in China could push global warming out of control. But the report these articles were based on was deeply flawed. The numbers were derived from the mix of fuels used by China as a whole — not the actual energy mix used by miners. Because much of China’s electric grid is powered by coal, these researchers then assumed that Bitcoin must be equally coal-dependent. Here’s why that’s inaccurate:
Miners are incentivized to find the cheapest energy sources available. That generally means excess power (electricity that would otherwise be wasted) and/or sustainable energy, which is plummeting in price.
Half of global mining takes place in Sichuan, China, where excess hydroelectric power allows mining to be fueled by 95% renewable energy.
75% of miners already use renewable energy as part of their energy mix.
Most important of all, the researchers behind the Cambridge Bitcoin Electricity Consumption Index have concluded that “Bitcoin’s environmental footprint currently remains marginal at best.”
As both crypto and green-energy technology mature, the reverse scenario is seeming more likely. Bitcoin miners are incentivized to go where power is cheapest. While that can mean some use of fossil fuels, the best way for miners to maximize profits is to find places with excess supply. In fact, Bitcoin is uniquely well-positioned to help make renewable energy cheaper and more accessible for everyone:
Renewable energy sources tend to have excess supply. When the grid can’t support that power supply, the power goes to waste.
Natural gas producers use a process called “flaring” to simply burn excess production, harming the environment and benefiting nobody. Bitcoin can convert this excess energy into value with no net increase in emissions.
By placing mining operations at the source of green energy, utilities can monetize their excess supply. In fact, at least one publicly-traded power company has explored participating directly in mining to capture value from excess supply that can be used to build out sustainable-energy operations.
By ensuring viable markets for renewable energy, Bitcoin incentivizes companies to build more green infrastructure, which further drives down the price of clean power. This virtuous cycle can actually contribute to the fight against climate change.
Many of the most alarming headlines come from a basic lack of understanding around how Bitcoin works. You might hear startling claims like, “Bitcoin would require 14x the world’s total electricity just to process the 1 billion credit card transactions that take place every day.” These numbers tend to come from conflating the energy cost of mining Bitcoin with the cost of transactions.
Energy consumption comes primarily from mining blocks on the blockchain, not from transactions. (The “mining” process accomplishes multiple goals — including both the generation of new bitcoin and the verification of new transactions. But the primary function of mining, as the name suggests, is generating new bitcoin.)
The energy spent is per block, not per transaction. As tools (like batching, Segwit, and the Lightning Network) allow parties to aggregate more transactions per block, energy costs per transaction will decrease.
Because Bitcoin is relatively new, the idea that it consumes as much energy as a country like Norway can seem shocking. But consider this: Norway’s GDP is around $400 billion. The total economic value that Bitcoin secures (its market capitalization) has been as high as $1 trillion. It’s not easy to make a direct comparison, but the important thing to remember is that everything uses energy. Whether that use of energy is considered justified or not depends in large part on the value that’s derived from the use of resources. And by that measure, Bitcoin is a substantially more efficient user of resources than many industries. Here’s some perspective:
The energy wasted by on-but-inactive household devices each year in the US alone could power bitcoin mining for 1.5 years.
Bitcoin has been found to consume far less than other financial systems: half that of the gold mining industry and less than one fifth of bank branches and ATMs.
As the biggest cryptocurrency, Bitcoin is often treated as a stand-in for the entire crypto space. This ignores the upgrade being currently made by the second-biggest cryptocurrency, Ethereum. The ETH2 upgrade is designed to make a vast range of economic activity — from lending and saving to minting NFTs — greener, cheaper, and faster.
Similarly, newer cryptocurrencies like Cardano are designed from the bottom up with sustainability in mind.
And when it comes to mining, the major stakeholders in the space are actively incentivizing the sustainable sourcing of energy in a variety of ways — including the launch earlier this year of the Crypto Climate Accord, which aims to reach 100% sustainable-energy production by 2025.
Elon Musk, who recently tweeted that Tesla would suspend accepting bitcoin as payment over fossil-fuel concerns, met with the biggest North American mining companies (including Argo Blockchain, Hive Blockchain, and Riot Blockchain) on May 23. Following the meeting, the mining firms announced the formation of the Bitcoin Mining Council — a consortium that aims to accelerate the adoption of sustainable-energy mining worldwide.
Ethereum is currently undergoing an upgrade which is moving the second-biggest cryptocurrency by market cap from a mining-based system to a more energy-efficient system called proof of stake. Proof of stake is already used by many cryptocurrencies.
Square recently announced a $10 million Bitcoin Clean Energy Investment Initiative to promote the use of clean energy in the mining of Bitcoin.
Just in the last week or so, several major mining firms announced green initiatives: Greenidge Generation Holdings said its New York Bitcoin mining operation would become carbon neutral on June 1. And Argo Blockchain announced new operations in Canada using mostly hydroelectric power.
Argo also recently joined mining firm DMG Blockchain in the Crypto Climate Accord (CCA). The CCA is an initiative launched by the private sector that pledges to help the mining industry to transition to 100% sustainable-energy production by 2025 and net-zero carbon emissions by 2040.
Coinbase Ventures recently invested in Crusoe Energy — a firm that harnesses natural gas producers’ excess “flare” energy for crypto mining and other productive uses.
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