Is Direct Air Capture Viable?
Whether Direct Air Capture (DAC) is viable or not has ignited much debate. On one hand, it is seen as a promising technology for removing carbon dioxide (CO₂) directly from the atmosphere, while on the other hand, there is concern that the technology is unproven and expensive.
However, with enough investment, government support, and technological advancements, DAC is set to become an indispensable tool in combating climate change. And it is starting to attract the attention of policymakers and business leaders as the technology continues to develop.
But first, what is Direct Air Capture? DAC involves extracting CO₂ from the air using advanced chemical processes. Essentially, DAC acts as a giant vacuum for atmospheric CO₂, which could help mitigate the damaging effects of greenhouse gases.
Is Direct Air Capture Technically Viable?
From a technical perspective, DAC is certainly feasible. The process works, and pilot plants are already running successfully. Furthermore, companies like Climeworks have built operational DAC facilities, demonstrating the ability to extract CO₂ on a small to medium scale.
However, the technology still faces efficiency challenges due to the low concentration of CO₂ in the atmosphere (about 0.04%), which makes it inherently energy intensive.
For DAC to work effectively on a large scale, the energy source needs to be renewable, and the carbon capture process itself needs to be refined.
Every new technology goes through phases of innovation, failure, refinement, and eventually, success. With continued research and development, DAC systems are becoming more efficient and affordable.
Economics of Direct Air Capture
Critics often say that DAC is too expensive and unproven. It’s true that DAC technology is relatively new, and as with all new technologies, not every project has been a success. But progress requires experimentation and, crucially, investment.
Direct Air Capture Cost
Currently, DAC is a relatively expensive method of carbon capture. Estimates place the costs anywhere from $600 to over $1000 per tonne of CO₂ captured, depending on the technology and the size of the operation. The aim is to reduce this to under $150 per tonne of CO₂ captured.
The high costs are mainly due to the energy required to run the fans, compress the CO₂, and regenerate the capture chemicals. To make DAC more economically viable, there are several DAC companies that are making headway with energy reduction innovations in the materials used and the capture process itself. (See: NEG8 Carbon’s DAC technology)
Off-Grid Renewable Energy
Since Direct Air Capture parks are location flexible, that is they can be located anywhere in the world and are not bound to emission sources, they are ideally positioned to use off-grid renewable energy that do not interfere with the local community’s energy supply. This means they don’t compete with or drain energy from existing grids, which makes DAC more sustainable and feasible on a large scale.
Future Cost Reductions
There is optimism around reducing the cost of DAC – the advances in technology, increased investment, and economies of scale as more DAC plants are built – all contribute to bringing down the price.
Moreover, the development of carbon markets would provide further financial incentives for DAC. If captured CO₂ can be used in industrial applications, it would add economic value, thereby creating a circular carbon economy where carbon is treated as a resource rather than a waste product.
Governments and private investors are beginning to recognise DAC’s importance in achieving net-zero emissions, particularly for sectors like transportation and heavy industry, which are difficult to decarbonise by other means.
Safety and Cost of CO₂ Transportation and Storage
In addition to energy needs, DAC requires infrastructure for both CO₂ storage and transport. Captured CO₂ must be safely stored underground, requiring appropriate geological sites and secure transport mechanisms.
The safety and cost considerations of CO₂ storage can be met by using Direct Air Capture rather than point source carbon capture (see Direct Air Capture vs Point Source). DAC can be located at the site where sequestration and/or utilization takes place, or near a pipeline out to sea for storage in depleted oil wells. This slashes the transport costs and takes out of the equation the safety issue of running CO₂ pipelines through urban areas.
Additionally, DAC captures CO₂ directly from the atmosphere, producing much purer CO₂ compared to emissions from industrial flues, which often contain a mix of harmful gases
Scalability and the Role of DAC in Climate Action
Is DAC Too Small to Matter?
Another argument against DAC is that it’s simply not enough—the immense amount of CO₂ already in our atmosphere is too large, and DAC is a drop in the ocean.
It’s true that DAC alone won’t solve the problem. But as the technology improves and costs decrease, scaling up will become possible. The goal is to see thousands of DAC farms across the globe, capturing hundreds of millions of tonnes of CO₂ each year. As public and private sectors invest in these technologies, the impact will grow significantly.
The comparison with renewable energy growth is key: just as solar and wind farms expanded over the last decades, DAC farms can and must grow in number. This isn’t about small, individual actions—it’s about a collective effort to deploy serious, large-scale solutions.
Can DAC Scale Up?
Scalability remains one of the core issues for DAC. To make a serious impact, the technology must be deployed on a vast scale. Estimates suggest that to capture just 1 gigatonne of CO₂ annually—still only a fraction of global emissions—thousands of large DAC plants would be required. (Statista.com: global carbon dioxide emission from fossil fuels and industry in 2023: 37.55 GtCO₂)
This scale of deployment would necessitate investment and coordination on the level of the current fossil fuel industry. While this is a formidable goal, it is not unattainable with the right combination of technological, economic, and political support.
DAC as a Complement Strategy to Emission Reductions
It is important to understand that DAC alone will not solve climate change. Instead, it should be seen as one part of a broader climate strategy. The technology is particularly relevant for hard to abate sectors, such as aviation and certain agricultural activities, where reducing emissions is extremely challenging. In these cases, DAC can act as a valuable tool to remove the remaining CO₂ that cannot be eliminated through conventional means.
For more on the urgent need to mitigate climate change and DAC’s role in that effort, see: Why Direct Air Capture?
Summary: The Pros and Cons of DAC
Advantages
Reduces Atmospheric CO₂:
The main advantage of DAC is its ability to directly reduce the amount of CO₂ in the atmosphere. This is essential for mitigating climate change and helps to counteract emissions that are difficult to avoid and captures the CO₂ that has already been emitted over the last 200 years by human activity.
Flexible Deployment:
Unlike other carbon capture technologies, DAC plants can be set up almost anywhere, as they are not tied to emission sources. This flexibility allows DAC to be a versatile tool in our climate strategy.
Economic Opportunities:
Captured CO₂ can be used in various industries, such as synthetic aviation fuel (SAF) or enhanced agricultural products, creating a market for CO₂ and reducing costs.
Disadvantages
High Costs:
As mentioned, the current cost of DAC is high, between $600 and $1000 per tonne of CO₂ captured. Efforts to reduce this cost to below $150 per tonne by 2050 are ongoing but will require advancements in technology and scale.
Energy Intensive:
DAC uses a lot of energy, which must be sourced sustainably for the technology to be beneficial. DAC needs to be developed to be more energy efficient and use off-grid renewable energy as the energy source.
Logistical Challenges:
Capturing CO₂ is just one part of the equation. Safe storage and transport infrastructure must also be factored in and locating the DAC park near the storage and/or utilization site is the answer.
(For more, see: The Advantages of Direct Air Capture)
Future Prospects
The coming decade is a watershed time for the development of DAC technology. Improvements in efficiency, new materials, and design innovations are expected to drive down costs and increase viability.
Governments are also stepping up, offering incentives and funding to promote DAC technology, recognising its potential in achieving climate goals.
Imagine the world ten years from now, with as many DAC farms as we currently have solar farms. It’s not unrealistic. The world needs both renewable energy sources and large-scale DAC parks that address the carbon that’s already in the atmosphere.
With the right investment, government support, and continued technological developments, DAC can become an important part of a broader strategy for reducing atmospheric CO₂.
For more:
Hard to Abate Industries and the Decarbonisation Challenge