DACCS
What you need to know about DACCS
- 1DACCS stands for Direct Air Carbon Capture and Storage and is an engineered carbon removal solution.
- 2It does not require any carbon feedstock (such as biomass), since it captures CO₂ directly from the atmosphere.
- 3There are several methods to directly capture the CO₂ from the air, which can then be paired with different sequestration solutions that can guarantee storage for thousands of years.
- 4As a closed-loop system, DACCS ensures high levels of accuracy in Measurement, Reporting, and Verification (MRV), making it one of the most reliable carbon removal methods available today.
- 5DACCS relies on abundant renewable electricity to perform the capture process, and on large sequestration sites — including certain types of geological formations.
How direct air capture and storage works
Despite having major implications for climate change by trapping heat via the greenhouse effect, CO₂ is actually a relatively small percentage of the overall makeup of the atmosphere — about 0.04%. That means to remove CO₂ from a given quantity of atmospheric air often requires large amounts of air to be collected — often using fans. That air is channeled through machines where a series of chemical processes remove the CO₂ to yield a pure, compressed gas, liquid, or solid carbonate that can be then stored or used.
Here’s more detail on the steps:
- CO2 capture: Large fans draw in ambient air into machines, where chemical filters or sorbents capture CO2 molecules while allowing the rest of the air to be released back into the atmosphere.
- Separation: Once the filters are saturated, the CO₂ is released from them using heat or another process. The almost pure CO₂ is then captured and compressed.
- Sequestration: The captured CO₂ is safely stored, typically by injecting it into geological formations. Alternatively, it can be used to produce durable materials like concrete.
Direct Air Capture (DAC) technologies usually perform the first two steps only, and the sequestration is often performed by specialized partners. If a DAC solution is used for the purpose of using the captured CO₂ in a method that will re-release the carbon, the process is not considered to be DACCS or even a method of carbon removal — and will not meet Patch’s project acceptance criteria.
Project showcase webinar: DACCS
In our webinar with AspiraDAC and CarbonCapture, we explore direct air capture technology, it’s benefits and challenges.
Why is DACCS important for climate change?
DACCS has become increasingly a key focus for scientists, project developers, governments, and corporations. There are three main reasons why. First, some emissions are extremely difficult or costly to eliminate, particularly from sectors like agriculture, aviation, and heavy industry. Even with aggressive decarbonization, these "hard-to-abate" emissions will likely persist — resulting in the need for durable carbon removal and storage.
Second, we've already emitted enough CO₂ to exceed safe atmospheric levels. Even if we stopped all emissions immediately, we'd still need to remove existing CO₂ to return to safer levels around 350 ppm. Current levels exceed 400 ppm and continue rising.
Third, we're likely to overshoot climate targets — at least temporarily. Most pathways to limiting warming to 1.5°C rely on removing 5-10 gigatonnes of CO₂ annually by 2050. This provides a critical buffer against short-term overshoot while giving more time for the challenging transition away from fossil fuels.
The IPCC and major climate models now include significant carbon removal in their scenarios for meeting Paris Agreement goals. While emissions reduction remains the primary priority, carbon removal has become a necessary complement — not a replacement — for aggressive decarbonization efforts.
DACCS complements other natural and hybrid carbon removal methods by offering a highly durable and measurable solution. Unlike nature-based projects, which are susceptible to risks like wildfires or deforestation, DACCS projects can ensure the permanence of CO₂ storage for thousands of years.
Important considerations for DACCS projects
DACCS and PSC
The major difference between DACCS and Point Source Capture (PSC) solutions is that PSC is implemented directly within industrial processes that emit carbon, capturing it at the emissions source. Therefore, PSC is considered a solution that prevents emissions from being released into the atmosphere, and is not a carbon removal solution.
DACCS and EOR
Some DACCS projects use the captured CO₂ for Enhanced Oil Recovery (EOR), a procedure that enables more fossil fuels to be extracted from wells. While using captured CO₂ could mitigate some of the total net carbon emissions of an oil well, ultimately it directly supports the release of greenhouse gas emissions. As such, Patch does not support solutions that involve CO₂ utilization for EOR purposes.
DACCS and utilization
If the CO₂ captured through DAC is used in processes that eventually release it back into the atmospheres — such as in the gasified beverage industry — the process does not qualify for carbon removal since it does not sequester the captured carbon.
Carbon credits and DACCS
DACCS carbon credits are considered premium due to their high durability and integrity. These credits are favored by organizations seeking long-term climate impact because they provide:
- Permanence - CO₂ storage through DACCS is designed to be irreversible, ensuring no re-release into the atmosphere.
- Certainty - The closed system with direct measurements allows for precise monitoring and verification of carbon removal amounts.
- Scalability - Experts estimate that DACCS could remove up to 5 gigatonnes of CO₂ per year by 2050 when heavily commercialized.
Although DACCS credits are currently more expensive than those from nature-based solutions, their long-term impact and reliability make them a critical component of global carbon removal strategies.
The history and future of DACCS
The concept of DACCS as a solution for climate change emerged in the late 1990’s, but the technology only began gaining momentum in the 2010s. It is a scalable solution to address the billions of tonnes of CO2 that need to be sequestered annually. DACCS is a critical component in the portfolio of carbon removal solutions that can help achieve safe atmospheric CO₂ concentration levels.
Despite several barriers to the large-scale deployment of DACCS — like reducing both the cost and energy use per tonne of carbon, the technology is rapidly gaining ground. Progress in research, development, and the transition from lab to field applications has accelerated the space from just a handful of DAC facilities developed before 2020 to over 50 companies working on diverse solutions in 2024.
DAC technology has several major projects worldwide. Climeworks operates the Orca plant in Iceland, which captures 4,000 tons of CO₂ annually and stores it underground through mineralization in basalt rock formations. Their larger facility Mammoth, became operational in May of 2024, and aims to capture 36,000 tonnes annually.
Carbon Engineering has significant projects in development in the U.S. and Canada. Their Stratos project, currently under construction in Texas' Permian Basin in partnership with 1PointFive, is slated to become the largest such facility in the world, capturing 500,000 tonnes annually.
Today, both policymakers and private investors are prioritizing research and development for DACCS. The governments of the United States and Canada have committed to procuring this type of carbon removal, making significant investments in R&D.
The U.S. Department of Energy (DOE) launched the Carbon Negative Shot initiative, which includes a $3.5 billion investment in DAC hubs through the 2021 Bipartisan Infrastructure Law. In 2023, the DOE selected two initial projects to receive up to $1.2 billion each: Project Cypress in Louisiana and South Texas DAC Hub. These hubs aim to capture at least 1 million metric tonnes of CO₂ annually.
With the global energy supply becoming greener, DACCS is expected to evolve into a more efficient and less risky solution.
Energy use in DACCS
One of the major challenges facing the scalability and practicality of DACCS as a methodology is the energy use required to power existing technology. In particular, energy is required for three discrete processes in many DACCS projects:
- Regeneration Energy: Breaking CO₂-sorbent bonds requires significant heat (800-1100°C for liquid systems, 80-120°C for solid sorbents)
- Fan Power: Moving large volumes of air through contactors requires substantial electricity
- Compression: Compressing captured CO₂ for transport/storage needs additional energy
Current estimates range from 5–10 gigajoules per tonne of CO₂ captured. For context, this means capturing 1% of global CO₂ emissions would require roughly 10% of global energy production.
The key focus is reducing regeneration energy through better sorbent materials and heat integration.
The durability of DACCS
The effectiveness of DACCS depends on the durability of its storage solutions. Geological storage, such as injecting CO₂ into deep rock formations, is highly secure with minimal risk of leakage. Innovative approaches like mineralization — where CO₂ reacts with specific rocks to form stable minerals — further increase the type of permanent solutions. Using captured CO₂ in durable construction products like cement and concrete can also lock away carbon, avoid emissions, and provide other economic benefits.
DACCS projects can be located in best siting conditions that combine low cost and abundant renewable energy sources and storage. The facilities don’t require vast land areas for deployment, contrary to many nature-based solutions.
This solution is technology heavy, which also benefits from economies of scale. As it is deployed in larger volumes, construction of equipment can be done at mass scale and used for long periods. Its closed loop nature also provides easy, reliable, and low cost MRV deployment, making it a great candidate for carbon crediting.
Most of DACCS projects are paired with geological sequestration, which is thought to be capable of sequestering carbon for thousands of years with relatively unlimited storage volumes and low leakage potential. This makes most credits permanent with certification of permanence deemed immediate or soon after injection.
This engineered solution requires relatively high amounts of energy during its operations compared to other solutions. Because of that, projects should procure renewable energy that does not compete with other uses, or build renewable energy projects particular to the project itself.
As a purely technological solution, DACCS often requires a lot of engineering work, a chemical filter that may be expensive, and a lot of energy to power the process. All of those factors contribute to the current high cost of this solution, though economies of scale are capable of driving these costs down over the medium to long term.
Significant financial investment is needed to build and operate DACCS, heavily contrasting with other carbon removal solutions. Its scalability depends heavily on government policies and subsidies, or advance purchases from private companies. This support is now seen in Europe and North America, but it needs to be spread across other regions to make it a global solution.
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