Cryptocurrency mining, the process of securing digital transactions and generating new coins, has gained significant traction in recent years, but it comes with a hidden environmental cost. This crypto mining boom, driven by soaring prices and widespread adoption, poses major challenges for climate, water, and land resources according to new research by United Nations scientists. While crypto mining plays a crucial role in maintaining decentralized financial networks and preventing double-spending, the energy-intensive process of solving complex cryptographic puzzles through specialized mining hardware has raised concerns about its environmental impact.
As the cryptocurrency market continues its meteoric rise, akin to a modern-day gold rush, it is essential to explore the environmental footprint of crypto mining activities, the key contributors, regional disparities, and potential solutions to mitigate these challenges. This article delves into the hidden environmental costs associated with crypto mining, shedding light on an often-overlooked aspect of this burgeoning industry.
Energy Consumption and Environmental Impact of Crypto Mining
According to a study published by the United Nations University and Earth’s Future journal, the global Bitcoin mining network consumed a staggering 173.42 Terawatt hours of electricity during the 2020–2021 period. If Bitcoin were a country, its energy consumption would have ranked 27th in the world, surpassing nations like Pakistan with a population of over 230 million people.
Electricity Usage and Carbon Footprint of Crypto Mining
The resulting carbon footprint of Bitcoin mining during this period was equivalent to burning 84 billion pounds of coal or operating 190 natural gas-fired power plants. To offset this massive carbon footprint, approximately 3.9 billion trees would need to be planted, covering an area nearly equal to the Netherlands, Switzerland, or Denmark, or 7% of the Amazon rainforest.
Water and Land Footprints of Global Bitcoin Mining Activities
Bitcoin mining activities also have significant water and land footprints. During the 2020–2021 period, Bitcoin’s water footprint was comparable to filling over 660,000 Olympic-sized swimming pools, exceeding the current domestic water needs of more than 300 million people in rural sub-Saharan Africa. The land footprint of worldwide Bitcoin mining activities during this period was 1.4 times the area of Los Angeles.
Reliance on Fossil Fuels and Renewable Energy Sources
The UN scientists’ report reveals that Bitcoin mining heavily relies on fossil energy sources, with coal accounting for 45% of Bitcoin’s energy supply mix, followed by natural gas at 21%. Hydropower, a renewable energy source with significant water and environmental impacts, is the most important renewable source of energy for the Bitcoin mining network, satisfying 16% of its electricity demand. In contrast, solar and wind energy sources only provide 2% and 5% of the total electricity used for Bitcoin mining, respectively.
Key Contributors and Regional Differences
Top Crypto Mining Countries and Their Environmental Impacts
China, by a large margin, has been the biggest Bitcoin mining nation. To offset the carbon emissions from China’s coal-intensive Bitcoin mining operations in 2021–2022, about 2 billion trees should be planted, covering an area equivalent to the sum of Portugal and Ireland or 45,000 times the area of Central Park in New York City. Aside from China, the world’s top 10 Bitcoin mining nations in 2020–2021 included the United States, Kazakhstan, Russia, Malaysia, Canada, Germany, Iran, Ireland, and Singapore.
Together, the top 10 Bitcoin mining countries in terms of environmental footprint are responsible for 92–94% of Bitcoin’s global carbon, water, and land footprints. The rankings of countries in terms of the environmental impacts of their Bitcoin operations change depending on which environmental footprint is considered.
Role of Cheap Electricity in Attracting Crypto Mining Operations
Countries with low electricity prices, like Kazakhstan, where electricity price is three times cheaper than that in the US, are Bitcoin mining heavens providing major financial incentives for Bitcoin mining that is heavily reliant on non-renewable energy sources.
Variations in Environmental Impact Based on Energy Sources
“Because countries use different sources of energy to generate electricity, their electricity production impacts on climate, water, and land are not the same,” said Dr. Sanaz Chamanara, the lead author of the study and an Environmental, Social and Governance (EGS) Research Fellow at UNU-INWEH.
Norway, Sweden, Thailand, and the United Kingdom are among the countries that make it to the top 10 list when the water or land footprint of their Bitcoin mining activities is taken into account. This is because each country uses a unique mix of energy sources to produce electricity, having different water, carbon, and land footprints, making the relationship between Bitcoin’s electricity use and environmental footprints non-linear.
For example, Ireland ranks ninth in terms of electricity use for Bitcoin mining. But the Bitcoin mining sector in this country has the sixth highest carbon footprint globally due to its high dependency on fossil sources of energy for electricity production. In contrast, Canada is the sixth Bitcoin miner of the world in terms of electricity use but the ninth emitter of greenhouse gases for Bitcoin mining thanks to the smaller role of coal and higher role of nuclear and natural gas in its energy supply portfolio compared to some other countries in the top Bitcoin miners list.
Challenges and Potential Solutions for Crypto Mining
Concerns with Proof-of-Work Mining and Price Volatility
The massive energy consumption of cryptocurrency mining threatens to undermine decades of progress towards achieving climate goals, and threatens grids, utilities, communities, and ratepayers. Bitcoin, the largest cryptocurrency by market capitalization, suffers from astronomical levels of energy consumption due to its reliance on the proof-of-work (PoW) consensus mechanism. PoW requires miners to solve computationally intensive mathematical puzzles, driving them to maximize their “hash rate” – the number of potential blocks that can be tested every second. This process is incredibly energy-intensive, demanding over 15 gigawatts of energy at any one time, with an annualized consumption of 138 terawatt hours.
The large energy usage associated with PoW mining is an inevitable consequence of the fundamental nature of its algorithms. As the price of Bitcoin comes down, smaller profit margins mean industry players are likely to seek out the cheapest electricity possible, which may not always be the cleanest. Furthermore, there are concerns about the ability of Bitcoin miners to be relied upon for demand response services on power grids, as high prices may incentivize them to prioritize mining over limiting power usage, putting increased pressure on stressed grids.
Need for Regulatory Interventions and Technological Advancements
State, local, and federal policymakers and regulators can help ensure cryptocurrency mining does not undermine climate or health goals, or adversely impact ratepayers. Local and state officials can enforce pollution and noise ordinances, develop careful zoning codes, and – in cases where municipalities run the electric utility – develop tariffs that protect existing ratepayers. Utility regulators can influence or bar problematic power purchase agreements, create protective electricity rates or system benefits charges, and ensure that mining facilities do not increase electricity or capacity costs for existing customers. Grid operators can develop comprehensive guidance and rules around the interconnection of high-density loads, study the impact of cryptocurrency mining on congestion, resource adequacy, and wholesale market prices, and create rules that minimize the impact on other customers. Environmental regulators at all levels should consider affirmative regulation to minimize the local health and environmental impacts cryptocurrency mining places on local communities.
One potential regulatory approach is section 111(d) of the Clean Air Act, which allows the EPA to develop regulations specifying “standards of performance” for sources that “contribute significantly to air pollution which may reasonably be anticipated to endanger public health or welfare.” As there are existing consensus mechanisms like proof-of-stake that are more energy-efficient than PoW, the “adequately demonstrated” requirement may be met, though the applicability depends on how “sources” are defined. States could also impose an outright moratorium on PoW cryptomining, as proposed in New York, or ensure they are not subsidizing wasteful operations through direct spending, forgone revenue, induced transfers, or transfer of risk.
Ultimately, with lawmakers increasingly looking at the effects of Bitcoin mining, lowering energy usage by moving away from PoW is a necessity. Ethereum has already transitioned to the far less energy-intensive proof-of-stake consensus mechanism, reducing its electrical usage by over 99.9%. The “Change the Code, Not the Climate” campaign aims to motivate Bitcoin to follow suit and move away from PoW toward a less energy-intensive consensus mechanism.
Importance of Renewable Energy Procurement and Emissions Tracking
With emissions on the scale of entire countries, it is imperative for Bitcoin mining, in the absence of changing to a low-energy consensus mechanism, to be powered by new renewable energy, rather than drawing from existing renewable capacity. Because of the flexibility of Bitcoin’s load, miners who are conscious about their footprint should be able to contract renewable energy to power their operations. Unfortunately, public data shows that this is not currently the case, with miners largely contracting energy from fossil sources and basing sustainability claims on being co-located near renewables.
To drive further renewable energy generation and make meaningful claims about renewable energy procurement, the Renewable Energy (RE) Emissions Score was developed to assess the material impact of renewable energy procurement, prioritizing investment in high emissions areas and low-cost renewable projects. If Bitcoin mining is to continue, it must be powered by additional renewables so that it does not inadvertently increase required grid capacity and lead to more fossil generation.
The intensity of emissions from electricity use will decrease when the network is decarbonized, so United States stakeholders should address the issue of electricity use and emissions in cryptocurrency mining activities to support its growth potential. Cryptocurrency mining activities utilize a diverse global energy mix, ranging from water, solar power, wind, and other renewable sources. However, the use of cryptocurrency as a currency creates a large carbon footprint, as mining requires burning fossil fuels to produce high-energy electricity, exacerbating climate change. Additionally, mining equipment and electronic waste disposal contribute to pollution if not recycled correctly.
Conclusion
The crypto mining industry has experienced meteoric growth, driven by surging asset prices and widespread adoption. However, this boom comes at a substantial environmental cost. The energy-intensive process of solving complex cryptographic puzzles, especially for the popular proof-of-work mechanism, consumes staggering amounts of electricity, resulting in massive carbon emissions, water consumption, and land usage. These impacts, often concentrated in countries with cheap electricity sources and varying energy mixes, threaten to undermine progress towards climate goals and strain local resources.
While the environmental challenges posed by cryptocurrency mining are daunting, there are potential solutions on the horizon. Regulatory interventions, such as emission standards, zoning codes, and protective electricity rates, can help mitigate the adverse effects. Additionally, technological advancements like the transition to more energy-efficient consensus mechanisms, like proof-of-stake, and the procurement of renewable energy sources offer promising paths forward. Ultimately, addressing the environmental footprint of cryptocurrency mining will require a concerted effort from policymakers, industry players, and consumers to ensure a sustainable future for this rapidly evolving industry.
