Key Takeaways
- Chia cryptocurrency uses a proof‑of‑space‑and‑time system that relies on storing data on hard drives rather than performing energy‑intensive calculations.
- A recent study by researchers in Algeria and France found that Chia’s annual carbon footprint is likely between 0.584 – 1.402 million tonnes of CO₂‑eq, roughly 18 times higher than the 50,000 tonnes originally claimed by the Chia Network.
- The majority of emissions arise from the embodied carbon of the solid‑state drives (SSDs) and hard‑disk drives (HDDs) that must be purchased and frequently replaced for the plotting process.
- Plotting is a memory‑ and processor‑intensive step that wears out SSDs quickly—approximately 160 plot creations can destroy a brand‑new SSD—forcing miners to replace hardware and incur additional manufacturing emissions.
- Although Chia’s energy use during farming is low, the overall environmental impact is still two orders of magnitude larger than that of mainstream blockchains such as Ethereum.
- Chia Network’s CEO, Gene Hoffman, argues that the study overestimates impact by counting the full lifecycle of drives that would otherwise be discarded, and says upcoming upgrades (Proof of Space 2.0) will dramatically cut emissions.
- Despite being marketed as a “green” alternative to Bitcoin, Chia’s current implementation does not save the planet, though it remains far less energy‑hungry than Bitcoin’s proof‑of‑work model.
Introduction to Chia’s Consensus Mechanism
Chia positions itself as an environmentally friendly cryptocurrency because it replaces Bitcoin’s proof‑of‑work (PoW) algorithm with a proof‑of‑space‑and‑time model. Instead of miners solving cryptographic puzzles that consume massive amounts of electricity, Chia miners (called “farmers”) allocate unused storage space on hard drives. The more storage a farmer commits—and the longer it remains dedicated—the greater their chance of earning newly minted Chia (XCH) tokens. This shift was intended to slash the network’s direct electricity consumption while maintaining security and decentralisation.
The Two‑Step Process: Plotting and Farming
Participating in the Chia network involves two distinct phases. Plotting is a computationally heavy operation that creates cryptographic “plots”—large files stored on disk that encode the farmer’s commitment to the network. This step demands substantial CPU power, RAM, and especially fast solid‑state drives (SSDs) to write data quickly. Once a plot is generated, the farming phase begins; the farmer simply stores the plot and periodically proves to the network that the data still exists. Farming is relatively low‑power, typically performed on cheaper, slower hard‑disk drives (HDDs) that can remain idle for long periods.
Environmental Cost of Plotting: SSD Wear and Embodied Carbon
Researchers Soraya Djerrab, Clémentine Gritti, and colleagues measured the real‑world power draw of hardware while performing Chia tasks and incorporated the embodied emissions associated with manufacturing the storage devices. They discovered that the plotting process wears out SSDs rapidly; creating roughly 160 plots can render a brand‑new SSD unusable. Consequently, farmers must replace SSDs frequently, each replacement incurring the carbon cost of extracting raw materials, fabricating NAND flash, and transporting the drives. When these lifecycle emissions are added to the modest electricity used during plotting and farming, the network’s total carbon footprint balloons.
Quantifying Chia’s Carbon Footprint
By integrating direct power measurements with embodied carbon estimates, the study concluded that Chia’s annual carbon emissions likely range from 0.584 to 1.402 million tonnes of CO₂‑equivalent. Even the midpoint of this interval (~0.99 Mt CO₂‑eq) is about 18 times larger than the 50,000 tonnes originally claimed by the Chia Network. For perspective, this places Chia’s impact two orders of magnitude above that of Ethereum (which consumes roughly 0.01 Mt CO₂‑eq per year under its current proof‑of‑stake design) and far below Bitcoin’s ~157 TWh/year (~70 Mt CO₂‑eq), but still far from negligible.
Industry Response: Reuse of Discarded Drives
Gene Hoffman, CEO of Chia Network, contested the study’s framing, arguing that much of the storage used for farming comes from decommissioned data‑center drives that would otherwise be landfilled. He contended that attributing the full manufacturing footprint to Chia is misleading because those drives have already served a prior life and are being repurposed. Hoffman suggested that the paper’s numbers are “off a bit” rather than wildly inaccurate, emphasizing that Chia has created a secondary market for otherwise discarded hardware.
Upcoming Upgrades: Proof of Space 2.0
Looking ahead, Hoffman announced that a protocol upgrade dubbed Proof of Space 2.0 is slated for release in approximately two months. This update aims to reduce the storage and hardware demands of plotting, thereby lowering the frequency of SSD replacement and the associated embodied emissions. While details remain scarce, the Chia team asserts that the new design will make the network “even better” from an environmental standpoint, though independent verification will be needed to confirm any real‑world impact reductions.
Comparative Perspective: Chia vs. Bitcoin and Other Blockchains
Even with its higher‑than‑claimed emissions, Chia remains substantially greener than Bitcoin, which relies on energy‑intensive PoW mining that consumes comparable power to a mid‑sized country. Compared to newer proof‑of‑stake (PoS) systems like Ethereum, however, Chia’s footprint is still significantly larger due to the hardware turnover required for plotting. This nuance underscores that “green” labels in cryptocurrency must consider both operational energy use and the full lifecycle of the physical infrastructure involved.
Conclusion: Balancing Innovation and Sustainability
The Chia case illustrates a broader lesson for the blockchain sector: shifting from computation‑intensive consensus to storage‑based models can cut direct electricity consumption but may transfer environmental burdens to hardware production and waste management. Accurate sustainability assessments must therefore encompass embodied carbon, device longevity, and end‑of‑life handling. While Chia’s upcoming Proof of Space 2.0 promises improvements, the current evidence suggests that, without careful hardware management and recycling strategies, the network’s ecological advantage over traditional PoW systems is modest at best. Stakeholders—developers, miners, and policymakers—should weigh these factors when evaluating the true environmental impact of emerging cryptocurrencies.