Decarbonisation Technology May 2025 Issue

commercial-scale plants under development. But as promising as DAC is, it still faces significant hurdles before it can truly operate at the gigaton scale required to impact the global atmospheric concentration of CO₂. The fundamental question remains: Can we make DAC affordable, energy-efficient, and scalable in time to meet climate goals? The challenges are not just technical. They span cost, energy requirements, infrastructure, policy, and public perception. Without addressing these barriers, DAC risks being a breakthrough that never breaks through. Can DAC compete economically? One of the most pressing challenges is cost. Current DAC systems operate at a price of $250-$600 per ton of CO₂ removed, making it one of the most expensive carbon removal technologies available. In comparison, nature- based solutions like afforestation cost less than $50 per ton. For DAC to be viable, costs need to drop below $100 per ton – a price point considered feasible but only with significant technological improvements, economies of scale, and policy incentives. The main cost drivers are: • Adsorbent material costs: High-performance materials like MOFs and polymer-hybrid adsorbents are expensive to produce, limiting large-scale deployment. • Energy demand : The need for heat and electricity, especially in solvent-based DAC, makes operating costs high. • Infrastructure and deployment: DAC requires piping, storage, and integration with CO₂ sequestration or utilisation facilities, adding to costs. There is reason for optimism, though. Learning curves from solar and battery technologies suggest that, with scaling, costs could fall rapidly. Government incentives, like the US 45Q tax credit, are already pushing prices down, and industry-backed purchasing programmes are helping to create early demand for captured CO₂.

matter. The two dominant DAC approaches have vastly different energy footprints: • Liquid DAC (for example, Carbon Engineering) requires extreme heat (900°C+) to release CO₂, making it heavily reliant on natural gas with carbon capture or concentrated solar power. • Solid DAC (for example, Climeworks and Global Thermostat) requires significantly lower temperatures (80-120°C), making it easier to integrate with waste heat, nuclear power, or renewable electricity. One of the most promising developments is the integration of DAC with low-carbon energy sources. Future DAC plants could be powered by geothermal energy, as demonstrated by Climeworks, surplus renewable energy, or nuclear energy. Where does the captured CO₂ go? Capturing CO₂ is one thing; what to do with it is another challenge entirely. There are two main pathways: • Permanent sequestration : Injecting CO₂ into underground rock formations (such as basalt or depleted oil fields) for permanent storage. This is the only way to guarantee long-term carbon removal. • CO₂ utilisation : Using captured CO₂ to produce synthetic fuels, concrete, carbon fibre, or chemicals. However, many of these applications re-release CO₂ into the atmosphere, making them less impactful for long-term removal. Current infrastructure for CO₂ transport and storage is limited, meaning large-scale DAC will require billions in new investment. Governments are already funding DAC hubs and storage projects, with the US committing $3.5 billion towards regional DAC facilities. Can DAC avoid the ‘moral hazard’ debate? One of the biggest non-technical challenges DAC faces is public perception. Critics argue that DAC could be used as an excuse to delay emissions reductions, allowing industries to continue polluting under the assumption that CO₂ can simply be ‘cleaned up’ later. This is sometimes called the ‘moral hazard’ of carbon removal. To counter this concern, policymakers and scientists stress that DAC should complement,

A carbon-neutral solution needs carbon-free power

DAC is only effective if it removes more CO₂ than it emits, which means energy sources