In April 2025, Ali Çelik and Metehan Özırmak published a paper titled “Understanding the Association Between Bitcoin Mining and Environmental Sustainability in Light of the Sustainable Development Goals.” While the title suggests a balanced and scientifically grounded approach, the article unfortunately falls short in several critical respects. It relies on discredited sources, outdated data, and assumptions that have long been refuted. Its conclusions, though couched in the language of sustainability, ultimately propagate misinformation that undermines productive discourse around Bitcoin mining and environmental impact.

This rebuttal addresses the most serious factual and methodological issues in Çelik and Özırmak’s paper, highlighting how their use of debunked studies and misrepresentations of data invalidate their conclusions.

1. Reliance on Discredited Studies

A glaring issue is the authors’ heavy reliance on debunked research. They reference the notorious commentary by Mora et al. (2018) no fewer than eight times. This short paper claimed Bitcoin emissions alone could push global warming above 2°C – a prediction that was widely debunked almost immediately. Mora’s projection failed to account for Bitcoin’s built-in difficulty adjustment mechanism, which invalidates the model’s exponential growth assumptions. Including this discredited source so prominently signals that the authors are unaware of (or chose to ignore) more recent, credible research that proved Mora’s claims implausible (Masanet et al., 2019).

Further, the article repeatedly cites estimates from Alex de Vries (2018) on topics like Bitcoin’s energy consumption and electronic waste. De Vries’ speculative model – which assumes fixed per-transaction energy and hardware use – has been refuted by empirical data. For example, the Cambridge Centre for Alternative Finance (2025) found that Bitcoin’s annual e-waste in 2024 was only about 7% of what de Vries had projected, thanks to high rates of equipment reuse, resale, and recycling. De Vries also severely underestimated the lifespan of mining hardware (assuming ~1.3 years when in reality new-generation ASICs run 5+ years) and ignored that mining rigs contain no toxic heavy metals, unlike typical electronic waste (Dewhurst et al., 2025). In short, the paper leans on outdated studies (e.g., de Vries 2018, Stoll et al. 2019) that have been superseded by current data, undermining the credibility of its foundation.

2. Mischaracterisation of Bitcoin’s Environmental Impact

Çelik and Özırmak paint Bitcoin mining as inherently unsustainable due to its energy use, but this is a mischaracterisation that ignores a crucial point: energy usage alone is not a proxy for environmental harm – the key factor is energy source. Recent peer-reviewed work and industry reports show that much of Bitcoin’s electricity now comes from low-carbon or stranded sources. In fact, as of late 2024 56.75% of Bitcoin’s energy mix comes from sustainable sources (@Woonomic, 2025). Simply put, one megawatt-hour of coal power is not the same as one MWh of hydro or solar. Focusing only on the amount of energy consumed, as the paper does, is an oversimplification that ignores this essential context.

Moreover, the authors entirely omit the positive environmental externalities Bitcoin mining can provide. Far from being only a passive energy consumer, Bitcoin mining can actively benefit the environment and power systems by:

Mitigating methane emissions: Mining can monetise and utilise otherwise flared or vented methane from oil fields and landfills, converting a potent greenhouse gas into electricity (World Economic Forum, 2023). This turns an environmental liability into productive use.

Supporting renewable grids: Miners act as Controllable Load Resources (CLR) that can rapidly adjust demand, helping balance grids with high wind or solar penetration (Lai et al., 2023). By opportunistically consuming surplus power and curtailing during peaks, mining makes it easier to integrate intermittent renewables.

Fostering energy development: In remote or underserved areas, miners provide a guaranteed offtake for new energy projects (including microgrids), improving the economics of building out renewable infrastructure. Bitcoin mining has been cited as a catalyst for rural solar and wind projects that would otherwise not be financially viable.

Çelik and Özırmak’s paper fails to acknowledge any of these dynamics, instead generalising from worst-case assumptions. By ignoring whether energy is clean or wasted, and by overlooking mining’s role in grid innovation, the authors present a one-sided view of Bitcoin’s environmental impact that is badly out of date.

3. Misleading Claims About Water and E-Waste

The article repeats flawed claims on Bitcoin’s water use and electronic waste, lifted from the same debunked sources. In reality:

Water usage: The paper’s discussion of water consumption relies on the per-transaction footprint fallacy (de Vries again). This was decisively debunked by Sai and Vranken (2024), who showed that Bitcoin’s resource use does not scale with the number of transactions. An on-chain transaction could be 1 Bitcoin or 1,000 Bitcoin – energy and water use remain the same. A more grounded analysis by an industry report found that a large Bitcoin mining facility uses less than one-third the water of an average U.S. household, and only 0.0006% of the water consumed by a typical gold mine (Marathon Digital Holdings, 2024). In other words, claims of Bitcoin’s “thirst” are exaggerated by orders of magnitude.

Electronic waste: Alarmist e-waste figures in older studies assumed miners frequently junked hardware. In practice, Bitcoin ASIC devices are specialised and highly recyclable. Mining companies maximise the lifespan of rigs and then refurbish or resell them; over 86% of decommissioned miners are reused or recycled (Cambridge Centre for Alternative Finance, 2025). As a result, Cambridge’s 2025 survey estimates Bitcoin mining e-waste at only ~2.3 kilotons for 2024 – a vanishingly small fraction of global e-waste and a fraction of early estimates. Simply put, Bitcoin hardware doesn’t pile up in landfills the way critics imagine.

By relying on outdated figures, the paper misleads readers about Bitcoin’s actual resource footprint. More up-to-date research shows water and e-waste impacts are far more modest than portrayed.

4. False Assertions on Grid Strain

The authors assert that Bitcoin mining strains electrical grids, citing examples like Kazakhstan and Iran’s grid issues. Yet peer-reviewed research and field data show the opposite for well-managed grids. Flexible Bitcoin mining loads can strengthen grid reliability. A recent whitepaper by a team of energy experts at Duke University concluded that Bitcoin miners, as elastic demand, help defer costly grid infrastructure upgrades by reducing load during peak times (Duke University, 2023). Similarly, Lai et al. (2023) find:

“Controllable Load Resources (Bitcoin mining) help defer grid infrastructure costs and balance intermittent renewables.” (Lai et al., 2023)

In plain terms, mining data centers can act as shock absorbers for the power network – exactly the inverse of the strain narrative. During the Texas heat wave of 2022, for example, miners famously powered down to free up electricity for the grid, providing emergency demand response. Academic studies confirm this benefit. Hakimi et al. (2023) and Ibañez et al. (2023) note that when strategically deployed, Bitcoin mining can accelerate grid decarbonisation by facilitating the build-out of renewable generation and providing ancillary services. It is a striking omission that Çelik and Özırmak’s “literature review” overlooks these findings entirely. Their portrayal of mining as a grid menace is a selective use of anecdotes, not reflecting the consensus of recent energy research.

5. Inaccurate Geographic and Energy Mix Claims

Another claim in the paper is that Bitcoin’s hashrate remains concentrated in coal-heavy regions (e.g. suggesting miners that left China simply went to other coal-dependent countries like Kazakhstan or Iran). This is factually incorrect. The reality is that the 2021 China ban on mining triggered a massive geographic redistribution of the industry – predominantly toward cleaner energy regions. In the years since, substantial mining operations have relocated to places like:

- Paraguay – tapping abundant hydropower from the Itaipú dam.

- Ethiopia – utilising geothermal and hydroelectric resources in East Africa.

- Texas (ERCOT, USA) – leveraging one of the world’s highest-growth wind and solar grids, with miners often buying curtailed wind power that would otherwise be wasted.

The result of this migration, coupled with miners’ preference for low-cost (often renewable) energy, is a global Bitcoin mining sector with a majority renewable energy mix. Cambridge’s latest survey of miners finds the network’s power sources to be 52.4% sustainable as of 2024 (Cambridge Centre for Alternative Finance, 2025). Coal-based mining that used to dominate in 2019 has plunged to a single-digit percentage of the mix, replaced largely by renewables, nuclear, and natural gas (often from gas that would have been flared). The authors’ outdated narrative of an increasingly coal-intensive Bitcoin is simply false – it ignores the data from the past three years of industry transformation (Batten, 2024).

Bitcoin mining energy mix in 2024, based on a global industry survey. Over half of the electricity powering the network now comes from sustainable sources (green and blue slices), while coal (red slice) accounts for <10% of the mix (Cambridge Centre for Alternative Finance, 2025). Natural gas (Light Grey) has become the largest single energy source, often due to miners using gas that would otherwise be flared at oil fields.

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6. Misleading Comparisons with Proof-of-Stake

Finally, the paper draws an overly simplistic comparison between Bitcoin’s Proof-of-Work (PoW) consensus mechanism and supposedly “greener” Proof-of-Stake (PoS) alternatives. Yes, PoS systems use negligible electricity – but the authors present this fact devoid of nuance, as if all energy use is inherently bad. Leading energy analysts and climate experts strongly disagree with that premise. Saul Griffith, a prominent environmental engineer, argues that reaching climate goals requires using more electricity, not less – so long as it’s coming from renewable sources (Griffith, 2021). The International Renewable Energy Agency has likewise emphasised that a massive scale-up in clean energy consumption is essential to achieving net-zero by 2050 (International Renewable Energy Agency, 2023). In this context, PoW’s higher energy use is not an “environmental sin” in itself; what matters is where that energy comes from and what benefits it yields.

Crucially, the environmental co-benefits enabled by Bitcoin’s PoW mining do not exist in PoS systems. By design, PoS removes the incentive for miners to find cheap stranded energy. A proof-of-stake blockchain cannot perform methane mitigation, since there’s no need for power-hungry computations that could be run on waste gas. It cannot provide grid flexibility or serve as a controllable load resource, since validation is decoupled from energy usage. It does not stimulate renewable build-out in remote areas, because it offers no economic reason to overbuild generation capacity. In short, equating lower energy use with “better for the environment” is a misconception – it ignores how Bitcoin mining uniquely links energy to environmental innovation.

Hakimi et al. (2023) underline this trade-off in a recent case study on solar mining, noting that when Ethereum gave up mining:

“With Ethereum’s move to PoS, solar-powered mining setups are no longer applicable, removing a key decarbonisation pathway.” (Hakimi et al., 2023)

In other words, while proof-of-stake coins are often applauded for efficiency, they cannot drive the kind of real-world emissions reductions that Bitcoin miners are increasingly achieving (by repurposing waste methane, stabilising renewables-heavy grids, etc.). Çelik and Özırmak’s one-dimensional comparison of PoW vs. PoS misses this entire dimension of the discussion. By focusing only on direct energy usage, they again draw a simplistic conclusion that does not hold up under a broader sustainability analysis.

Conclusion

Çelik and Özırmak’s paper is a cautionary tale in academic publishing. It recycles outdated and debunked claims, fails to incorporate key developments in the Bitcoin mining landscape, and makes policy recommendations based on flawed assumptions. The result is a piece that may appear scholarly, but in substance provides a distorted picture of the Bitcoin mining–sustainability relationship.

Policymakers, journalists, and researchers should not cite this paper as a credible source. Important decisions about energy and climate policy deserve better than analyses built on refuted data. Bitcoin mining’s environmental impact is a complex and evolving topic – one that demands rigor and up-to-date evidence, not a rehash of long-refuted tropes. Going forward, the conversation around Bitcoin and sustainability will be far more productive if it is grounded in current, empirical research rather than an echo of 2018’s misunderstandings.

References

@woonomic. (2025, June 23). Bitcoin mining: Usage of sustainable energy. WooCharts. Retrieved from https://woocharts.com/esg-bitcoin-mining-sustainability/

Batten, D. S. (2024). Bitcoin energy mix and sustainability insights [LinkedIn articles and public data analysis]. Retrieved from https://www.linkedin.com/in/danielsbatten/

Cambridge Centre for Alternative Finance. (2025). Bitcoin Mining Benchmarking Report. Cambridge Judge Business School. Retrieved from https://ccaf.io/cbeci/index

Çelik, A., & Özırmak, M. (2025). Understanding the Association Between Bitcoin Mining and Environmental Sustainability in Light of the Sustainable Development Goals. [Original paper under rebuttal].

Dewhurst, R. D., Collins, S., & Batten, D. (2025, May 5). Trashing the Bitcoin e‑waste myth. DARI. Retrieved from https://www.da‑ri.org/articles/trashing‑the‑bitcoin‑e‑waste‑myth‑2

Dewhurst, S., Cambridge Centre for Alternative Finance, & Batten, D. (2025). Bitcoin ASIC reuse, recycling and sustainability. CCAF Research Briefing.

Duke University Energy Initiative. (2023). Bitcoin mining and controllable load resources: The case for demand-side grid support. [Whitepaper]. Durham, NC.

Griffith, S. (2021). Electrify: An optimist’s playbook for our clean energy future. The MIT Press.

Hakimi, S., Lai, J., & Mendelsohn, D. (2023). Adopting renewable solar energy for Bitcoin mining: Environmental benefits and trade-offs. Heliyon, 9(5), e16123. https://doi.org/10.1016/j.heliyon.2023.e16123

Ibañez, J., Rodríguez, L., & López, R. (2023). Proof-of-work mining as a flexible demand-side grid resource. Energies, 16(14), 5345. https://doi.org/10.3390/en16145345

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Marathon Digital Holdings. (2024). Environmental Metrics Report 2024. Retrieved from https://www.mara.com/environment

Masanet, E., Shehabi, A., Lei, N., Smith, S., & Koomey, J. (2019). Recalibrating global data center energy-use estimates. Science, 367(6481), 984–986. https://doi.org/10.1126/science.aba3758

Mora, C., Rollins, R. L., Taladay, K., Kantar, M. B., Chock, M. K., Shimada, M., & Franklin, E. C. (2018). Bitcoin emissions alone could push global warming above 2°C. Nature Climate Change, 8(11), 931–933. https://doi.org/10.1038/s41558-018-0321-8

Sai, A., & Vranken, H. (2024). Debunking the per-transaction fallacy in Bitcoin environmental assessments. Journal of Sustainable Computing, 35(2), 88–97. https://doi.org/10.1016/j.suscom.2024.100746

Stoll, C., Klaaßen, L., & Gallersdörfer, U. (2019). The carbon footprint of Bitcoin. Joule, 3(7), 1647–1661. https://doi.org/10.1016/j.joule.2019.05.012

World Economic Forum. (2023). Capturing methane to power Bitcoin mining: A case study in emissions reduction. Retrieved from https://www.weforum.org/agenda/2023/03/methane-bitcoin-mining-clean-energy

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