Bitcoin’s E-Waste Problem is Hiding in Plain Sight

As the popularity of Bitcoin mining and investments continues to surge, concerns over its environmental impact are mounting. The upcoming Bitcoin “halving” event that reduces the Bitcoin awarded to miners will impact the economics of mining Bitcoin. This will likely lead to thousands of new Bitcoin mining computers being purchased while older equipment is rendered unprofitable and discarded as e-waste. The industry already produces large amounts of e-waste from specialized computing equipment on top of hefty energy and water consumption. The industry needs to take responsibility for these impacts to prevent further harm to the environment and communities.

 

Highlights

• The April 2024 Bitcoin halving incentivizes faster, more powerful mining equipment to maintain profitability in the face of rising energy costs and diminishing returns.
• Rapid turnover of mining hardware creates large amounts of electronic waste (e-waste) as older, less efficient models are replaced by newer ones and are not recycled or reused.
• Transitioning Bitcoin to a new consensus algorithm could dramatically reduce the incentive for specialized mining equipment and the need for large amounts of cheap energy and water.

The competitive nature of Bitcoin mining and tight profit margins for companies incentivize the development of more powerful mining equipment – called Application-specific Integrated Circuits (ASICs) – for miners to remain profitable. Since ASICs are highly specialized computers that are built with the sole purpose of guessing numbers to mine Bitcoin, old equipment is discarded and not reused. This turnover of mining equipment stands to be accelerated by the halving. The pursuit of faster, more powerful hardware contributes to the generation of e-waste, posing another environmental challenge that needs to be addressed by the industry.

Bitcoin miner’s ability to break even depends highly on the price of Bitcoin to offset their energy and equipment costs. The Bitcoin network was designed so that the complexity of mining would increase when more companies participate, making it more difficult to guess the right solution and win new Bitcoin. Additionally, the rewards were programmed to be cut in half every four years. Known as the Bitcoin halving, this process is meant to control Bitcoin’s inflation rate and limit the total lifetime supply of Bitcoin to 21 million coins. As a result, participating in Bitcoin mining requires ASIC hardware and access to large amounts of cheap, consistent energy to participate without losing money. When Bitcoin was released in 2009, the reward for mining was 50 Bitcoin–after the fourth halving in April 2024, the reward will be only 3.125 Bitcoin. This creates a turnover of older and slower ASICs for miners to remain competitive and maximize profits.

E-waste from ASICs is an unreported but already potentially large source of e-waste. As of May 2021, researchers estimated that the entire Bitcoin network generated 30.7 metric kilotons of e-waste per year from ASICs that became unprofitable and obsolete. They also estimated that 64.43 metric kilotons of e-waste could be generated annually with a higher Bitcoin price based on the production of the most efficient available model when the research was conducted. While the scale of the issue is not clear, there are cases of irresponsible disposal. For example, during a period of low Bitcoin value in 2018, thousands of ASICs were found to have been discarded in China when they were no longer profitable. The amount of this hazardous waste could accelerate post-halving.

 

Hardware Life Cycles

In order to stay profitable when the Bitcoin reward is reduced by half, many miners have invested in the newest and most efficient machines. The lifespan of an ASIC is estimated to be 5-7 years, and even up to 10 years before the machine is not functional. But considering when an ASIC becomes unprofitable suggests a different end game. Often, machines become unprofitable in as little as 1-2 years. After this time, ASICs become too inefficient to be profitable, even if they are still functional. TheMinerMag reports that in 2023, it cost around $10,000-15,000 to mine a single Bitcoin. Wolfie Zhao, head of research at Blockbridge and author at TheMinerMag, was also quoted as saying that these costs could double by the 2024 halving, bringing the production cost to $20,000-$30,000 per bitcoin. Assuming the price of Bitcoin has not dramatically changed, such an increase in the cost of Bitcoin mining could force miners to invest in newer, more powerful ASICs to compete.

The turnover of ASICs has become faster over time based on changes in Bitcoin price, demand, incentives, and technological innovations. In anticipation of the halving, Bitmain’s Georgia operation imported 5.41 million kilograms (almost 6000 US tons) of the newest ASIC machines (Bitmain’s Antminer S19XP) between July 2023 and March 2024. The recent record high price of Bitcoin ($73,798 on March 14, 2024) and industry excitement leading up to new Bitcoin investment products offered by big financial companies like BlackRock and Fidelity, a spot Bitcoin ETP, also encouraged profit-seeking miners. For example, major mining companies CleanSpark Inc. and Riot Platforms Inc. reportedly spent $473 million and $415 million, respectively, on updating ASIC machines in preparation for the halving, according to TheMinerMag.

There is speculation that the halving could be beneficial to the environmental impacts of Bitcoin because it will reduce energy use, as only the most efficient ASICs will be operating. While miners will be driven to use the most efficient machines, there remains competition for cheap electricity. The halving has already spurred some mining companies to migrate machines to countries with cheaper electricity prices to stay profitable. The price of Bitcoin is also projected to increase after the halving, potentially offsetting any reduction in energy use due to newer ASICs. The halving may also lead companies to replace and dispose of old machines, driving up e-waste from the industry. Thus, there are unlikely to be any meaningful reductions in GHG emissions to match the scale of Bitcoin’s climate impacts. 

 

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• When the price of Bitcoin is low, mining is less profitable, and there is a greater incentive to use the newest and fastest ASICs. This is because the Bitcoin rewards from mining are worth less and companies need to keep operating costs low to make a profit.
• When the price of Bitcoin is high, mining is more profitable because the Bitcoin rewards have more value. This increases the demand for ASICs as miners are eager to participate in mining, and means older ASIC models may be profitable. 
• Mining operations may hold on to older ASIC models, and run them when it is profitable. Because the mining algorithm becomes more complex when more miners are participating, even these older models can become obsolete quickly.
• The overall increase in Bitcoin’s price and hype has also incentivized research and manufacturing to create more efficient machines quickly.
• Many expect that the 2024 halving will lead Bitcoin price to grow in the weeks leading up to and following the halving, meaning a greater incentive for miners to participate with the most profitable ASIC machines.
• The halving will likely mean smaller mining companies go offline or out of business, which also creates e-waste. Meanwhile, large mining companies with lower operation costs can invest in new ASICs and potentially discard or sell old ones.

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The life cycle of ASICs is opaque and difficult to track, but there are serious environmental and social concerns for the industry. Similar to other technology industries, raw materials like critical minerals for computer chips are nonrenewable materials that are essential for ASIC production. Mineral and metal extraction for electronics, especially microchips, has been connected to human rights abuses, including child labor and warfare, and is environmentally destructive. Electronics manufacturing has also been linked to poor labor conditions and human rights violations as industries work to make new products quickly and cheaply. 

ASIC manufacturers do not report on the sources of raw materials for production and do not participate in programs that set environmental or labor standards for product life cycles. For example, there are currently no mining manufacturers participating in the Global Electronics Council’s Electronic Product Environmental Assessment Tool, which assesses the sustainability of devices from resource extraction to product disposal. There are also no manufacturers with TCO certification, which is a sustainability certification for IT products and electronics. Production of semiconductors for ASIC hardware is also energy and water-intensive. TSMC, a major semiconductor producer in Taiwan, estimated that they would use more electricity than the city of Taipei in 2022. While TSMC has committed to transitioning to renewable energy by 2040, the industry progress so far has been disappointingly slow.

 

E-Waste

There are no environmental standards or oversight for ASIC machine disposal in the US or abroad. Major manufacturers, such as Bitmain, MicroBT, or Canaan, do not provide recycling or safe disposal programs for customers. Some companies, such as SunnySide Digital, have received and resold unwanted ASICs to miners overseas. Some mining companies have chosen to turn off mining hardware in hopes that the price of Bitcoin becomes favorable enough to turn them back on and profit. Operations that replace machines or supplement their fleet with additional hardware have given no insight into the disposal of obsolete and discarded e-waste. 

There is little evidence of responsible handling of e-waste by miners. Organizations that track global e-waste flows, such as the United Nations Sustainable Cycles program, lack insight about the industry. Considering that only 17.4% of e-waste is estimated to be recycled globally, it’s likely that these single-purpose ASICs are sent to landfills or incinerated when they become unprofitable. This suggests a serious environmental and social challenge beyond the energy and water demand of the industry. 

 

Solutions

The rapid obsolescence of ASIC hardware can lead to significant amounts of e-waste. By weight, ASIC machines are primarily generic materials like metal casings and aluminum, which should be straightforward to recycle or even reuse. But toxic chemicals in electronics make even proper recycling of ASICs risky for workers and the environment. Since e-waste from Bitcoin miners is not well-tracked or regulated, there is no certainty that e-waste is being treated as hazardous, staying out of landfills, or being incinerated. Considering the risks of e-waste and the resistance of the industry to make operations more regulated and transparent, recycling and reuse alone won’t be an adequate or safe solution. Mining companies, manufacturers, and financial institutions that offer Bitcoin services, such as ETPs, should engage with existing regulations and environmental standards for hardware life cycles and e-waste to ensure that the industry is working responsibly to reduce impacts.

Rather than attempting to band-aid over Bitcoin’s threats to the environment, a shift from the current proof-of-work (PoW) to another consensus mechanism is the essential solution for addressing the waste, energy, water, and social impacts of Bitcoin mining. Changing the Bitcoin network to another consensus algorithm eliminates the need for energy-hungry digital mining. For example, the proof-of-stake algorithm, used by cryptocurrencies like Ethereum, or proof-of-history used by Solana, does not require miners to strongarm others with computational power. Instead, miners can participate with nearly any device with Internet access. Removing the incentives for single-purpose, energy-gobbling machines reduces the opportunities for producing e-waste, as well as reducing energy and water use. Luckily, many consensus mechanisms exist, and there is an opportunity for innovation and collective action to transform Bitcoin’s PoW system.