How does cryptocurrency contribute to fossil fuel emissions?

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In February 2021, Tesla announced that it had purchased $1.5 billion in Bitcoin and planned to accept the cryptocurrency as payment, causing the price of Bitcoin to soar to record high numbers. However, three months later, Elon Musk disrupted the cryptocurrency market when he tweeted, “Tesla has suspended vehicle purchases using Bitcoin,” citing concerns about “rapidly increasing use of fossil fuels for Bitcoin mining and transactions, especially coal, which has the worst emissions of any fuel.” Overnight, the Bitcoin market dropped by almost 10 percent–so how founded are these environmental concerns in cryptocurrency mining, and could cryptocurrency have a clean energy future?


Key takeaways


  • Proof-of-work cryptocurrency, such as Bitcoin, requires a lot of energy to mine
  • Mining of cryptocurrency is largely powered by fossil fuels
  • Some cryptocurrencies are shifting to more energy efficient mining strategies
  • You can use the EnergySage Marketplace to compare quotes for solar panels that can power your cryptocurrency mining

What is cryptocurrency and how is it mined?

At its core, cryptocurrency is digital money. Like the money you may have in your wallet or bank account, you can use cryptocurrency to purchase goods and services. However, instead of using intermediaries–like brokerages or banks–for financial services, most cryptocurrency uses a decentralized blockchain network that is open for anyone to use. This blockchain is essentially a transaction ledger that tracks the records, or blocks, of when cryptocurrency transactions occur.

Bitcoin is the most traded form of cryptocurrency. There are a finite number of bitcoins that exist–21 million to be exact–but not all of them have been mined. What this means is that some bitcoins have not yet entered into circulation and therefore cannot be used in transactions. By mining for bitcoins, you can earn this digital currency without actually paying for it–think of it as if you go looking for gold and find some! Mining involves solving complex puzzles through a process called hashing, which essentially uses a mathematical function to generate a value from a string of text. 

These values, or hashes, serve as “proof-of-work,” meaning the value was difficult to produce, but easy to verify. Does all of this seem confusing? The important thing to consider here is that mining for cryptocurrencies that require proof-of-work, such as Bitcoin, require extremely sophisticated computers with high processing power, all of which consumes a lot of energy. Furthermore, as we continue mining for the finite number of bitcoins remaining, they become increasingly difficult to mine; therefore, each bitcoin requires more energy to enter into circulation as Bitcoin increases in value. 

How does mining for cryptocurrency impact the environment? 

While many Bitcoin enthusiasts have claimed that the energy used for mining comes from renewable sources, fairly recent reports have shown that this likely isn’t the case. According to a 2020 report by the University of Cambridge–an institution that has done extensive research on Bitcoin’s energy consumption–only 39 percent of proof-of-work mining is powered by renewable energy. When you consider that if Bitcoin were a country, it would rank 26th in energy consumption–ahead of countries like Malaysia, Sweden, and Argentina–this number is quite concerning. It’s estimated that about 65 percent of hashing is done by China, and within China about 36 percent is done in the province of Xinjiang (about 23 percent worldwide). 

Within Xinjiang, most electricity is still produced using coal plants, which means that a substantial portion of overall Bitcoin mining energy consumption is powered by coal. In April 2021, a huge coal mine in Xinjiang flooded, prompting a safety check that closed the mine for two days. Subsequently, Bitcoin’s hashrate (or, rate at which hashing is conducted) fell by 35 percent. While this number may have been exacerbated by the price of cryptocurrency dropping by about 14 percent around the same time as well, it’s safe to assume that the coal mine played a substantial role. 

Why did Tesla suddenly change course?

When Tesla purchased $1.5 billion in Bitcoin, it was already widely known that the cryptocurrency was contributing to fossil fuel emissions–so why did the company so quickly change its tune? Environmental, social, and corporate governance–or, ESG–criteria are becoming increasingly important standards for investors, which likely played a role in Tesla’s decision. 

Furthermore, the shortage of semiconductor chips is creating competition among unlikely companies. Semiconductor chips are used in many products, ranging from smartphones to computers to vehicles to microinverters in solar systems. While up to this point, Tesla has largely remained unscathed from the shortage, Elon Musk said in an April 2021 earnings call that Q1 included “some of the most difficult supply chain challenges that we have ever experienced in the life of Tesla,” which Tesla attributed to the semiconductor shortage as well as port congestion. Because cryptocurrency mining requires these semiconductor chips, the increased mining related to cryptocurrency has contributed to the shortage, forcing Tesla to compete for the precious semiconductor chips. 

Could the future of cryptocurrency be clean energy? 

Square, a company that has big stakes in Bitcoin, published a white paper titled “Bitcoin is Key to an Abundant, Clean Energy Future.” The white paper explains that Bitcoin mining could essentially serve as a storage solution for excess renewable energy produced during the day. If the energy can’t be stored or sold back to the grid, Bitcoin miners could use it to power mining. Square also opines that as renewable energy continues to fall in price, Bitcoin miners will use a larger portion to power mining; however, Square isn’t exactly an unbiased party (the founder has invested $220 million in Bitcoin), so we’ll see if that’s really the case. 

Some cryptocurrencies are already making strides to become more energy efficient. Ethereum, the second most traded cryptocurrency after Bitcoin, is in the process of changing its mining process. Instead of using proof-of-work like Bitcoin, it will use proof-of-stake, which essentially means it will shift its security make-up to require significantly less energy. If other cryptocurrencies like Bitcoin follow suit, this could be a game changer. 

Want to power your Bitcoin mining with renewable energy? On the EnergySage Marketplace, you can get and compare multiple quotes from solar installers. By shopping around, you can find an option that meets your needs and fits your price. If you’re not a homeowner, or aren’t interested in installing solar on your property, visit our Community Solar Marketplace to subscribe to a local community solar project. 


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About Emily Walker

Emily is the Content Manager & Research Analyst at EnergySage, where she enjoys making energy fun and easy to learn about! She has a background in environmental consulting and has degrees in Environmental Science and Biology from Colby College. Outside of work, Emily is pursuing a Master of Science from Johns Hopkins University in Environmental Science and Policy. She also loves hiking, tending to her collection of houseplants, and trying out new restaurants and breweries whenever possible.

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