Engaging in a Blockchain Energy Battle: Proof of Work vs Proof of Stake

Explore the energy impacts of cryptocurrency mining, the shift towards cleaner, more sustainable practices, and the debate between Proof of Stake (PoS) and Proof of Work (PoW) models.

Engaging in a Blockchain Energy Battle: Proof of Work vs Proof of Stake

Bitcoin and Ethereum continue to dominate the crypto space, yet the way they validate transactions differs fundamentally. Understanding their consensus models - Proof of Work and Proof of Stake - provides insight into some of blockchain's most challenging trade-offs. Today, we'll examine the debates surrounding their energy consumption. It's time to understand whether and how we can compare these two methods from an energy perspective.

Under the Hood of Cryptocurrencies

Let's recap: cryptocurrencies, such as Bitcoin and Ethereum, operate on blockchain networks. These networks consist of nodes that validate transactions and record them on a distributed ledger. The nodes reach consensus on which transactions to add to the ledger through mechanisms like Proof-of-Work (PoW) or Proof-of-Stake (PoS).

PoW chains, like Bitcoin, require nodes to compete to solve complex mathematical problems. This process consumes large amounts of computing power and electricity, particularly for miners.

On the other hand, PoS chains, such as Ethereum (which was not too long ago a PoW blockchain), allow nodes (or validators) to validate transactions based on the number of coins they hold. This approach requires less computing power and is therefore much more energy-efficient.

In Numbers

# PoW

Cryptocurrencies like Bitcoin, which operate on a proof-of-work mechanism, are notoriously energy-intensive. According to energy tracking studies such as Digiconomist and the Cambridge Bitcoin Energy Consumption Index (CBECI), Bitcoin's estimated energy consumption as of July 2021 ranged from 29.96 TWh to 176.98 TWh. In perspective, this range is equivalent to the energy consumption of entire countries like Sweden or Thailand. Moreover, Digiconomist's latest estimate reveals that Bitcoin's carbon footprint was 64.18 MtCO2 as of July 2021, aligning with emissions from countries like Greece and Oman.

When all minable crypto is considered, the energy usage is likely on par with global data centers. With an approximate cost of $0.04/kWh, Bitcoin's yearly electricity expenditure surpasses $15 billion. This high energy consumption is inherent to the proof-of-work model, securing the network through its intensive computational "work".

# PoS

Before "The Merge" in 2022, Ethereum's annual energy consumption fluctuated between 46.31 and 93.98 terawatt-hours (TWh). However, following the Merge, Ethereum's carbon footprint was dramatically reduced to 0.1 million tonnes of CO2 per year, and the energy usage for individual Ethereum transactions plummeted to as low as 0.03 kilowatt-hours (kWh).

The Merge was a significant upgrade that transitioned Ethereum from a proof-of-work (PoW) consensus mechanism to a proof-of-stake (PoS), resulting in an immediate and impressive reduction in the network's energy consumption by over 99.9%. Despite this substantial decrease, the energy consumption of Ethereum and other cryptocurrencies per transaction still significantly exceeds that of non-crypto networks.

The Merge brings down Ethereum’s network power consumption by over 99.9%
Before the Merge upgrade, in 2022, the energy consumption of Ethereum ranged between 46.31 terawatt hour (TWh) per year to 93.98 TWh per year.

Room for Improvement

Numerous cryptocurrency developers and companies have pledged to achieve sustainability targets such as net-zero emissions by certain dates. Let's examine the potential strategies and their impacts.

Network Efficiency Improvements

Technical upgrades are enhancing network efficiency and scaling to reduce crypto's carbon footprint.

Bitcoin is adopting innovations such as the Lightning Network, SegWit, and Taproot to shrink transaction sizes, enhance throughput, and facilitate new use cases. Additionally, renewables now account for 39% of Bitcoin's energy consumption. Following its transition to a Proof-of-Stake (PoS) model, Ethereum has managed to slash its energy usage by 99.9%.

Mining Materials

Miners are becoming more energy-efficient by upgrading to next-generation ASIC rigs, which offer a significantly higher hash rate per watt. They are also harnessing inexpensive renewable energy sources such as stranded flare gas or hydroelectric power. Further, they are leveraging the waste heat from mining operations for heating buildings and greenhouse farming, among other uses. Lastly, they are optimizing energy contracts to balance demands on the power grid.

What about Regulatory Bans?

Bans don't reduce energy usage; instead, they merely shift it elsewhere, often to less clean power grids. Allowing mining encourages the development and investment in renewable infrastructure. Outright bans are often performative. A reasonable policy acknowledges the complexities of the issue rather than oversimplifying it. Miners are subject to political fluctuations, gravitating towards regions with abundant energy and welcoming regulations; they go where they are treated best.

Is it really that problematic?

Given climate imperatives, many policymakers regard proof-of-work mining as wasteful. However, cryptocurrencies also enable financial access with minimal trust, providing a unique societal benefit. The debate involves balancing unquantifiable positives against tangible energy negatives, with compelling arguments on both sides.

Computational work in cryptocurrency mining draws significant environmental criticism. Nonetheless, it's crucial to remember that serious actions are being taken and are likely to continue, driven by various incentives.

Can you even compare?

Proof of Stake (PoS) consumes negligible energy as it simply requires staked coins rather than computation. However, both PoS and Proof of Work (PoW) models serve different purposes. Thus, efficiency comparisons between these dissimilar systems have limitations. PoW ensures security through provable physical investment, whereas staking relies more on trust in token holders.

Energy use certainly merits thoughtful critique, but simplistic judgments around efficiency often overlook the nuances. Both approaches have their merits, and the adoption of hybrid models or renewable energy sources could potentially enhance sustainability.


As we evaluate the impacts of cryptocurrency mining, particularly its energy consumption, it becomes clear that neither unbridled optimism nor reflexive skepticism serves well. This multifaceted issue requires an open-minded outlook, acknowledging both its potential transformative benefits and harsh realities.

That being said, cryptocurrencies are increasingly seeking to power their mining and validation operations using renewable energy sources or ways to upgrade their validation process without corrupting on the core principles. This transition towards cleaner power sources is a key aspect of the sector's efforts to become more sustainable.

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