DACCS

Direct Air Carbon Capture & Storage (DACCS) represents a group of advanced technologies at the forefront of climate action. Unlike traditional carbon capture which traps emissions at a specific source (like a factory), DACCS works by processing large volumes of ambient air to isolate and remove CO2 that has already been emitted. This makes it a crucial tool for addressing historical and dispersed emissions, providing a tangible way to lower the overall concentration of greenhouse gases in the atmosphere.

For governments, corporations, and investors in the climate finance space, DACCS is a key pillar of long-term decarbonization strategies. It provides a high-integrity method for generating carbon dioxide removal (CDR) credits, which are used to offset residual emissions that are otherwise impossible to eliminate.

How DACCS Works

The process can be broken down into four key steps, transforming atmospheric CO2 into a permanently stored asset:

• 1. Air Contact: Large fans pull ambient air into a collector unit, passing it over surfaces designed specifically to react with CO2.
• 2. Chemical Capture: The air flows over a specialized chemical filter. This is typically either a liquid solvent or a solid sorbent that selectively binds with CO2 molecules, letting other elements of the air pass through.
• 3. Release and Concentration: Once the filter is saturated with CO2, it is heated. This releases the CO2 in a concentrated, near-pure stream. The regenerated filter can then be reused for the next cycle.
• 4. Permanent Storage (Sequestration): The captured, concentrated CO2 is compressed and injected deep underground into carefully selected geological formations, such as saline aquifers or depleted oil and gas reservoirs. Here, it is permanently and safely sequestered, preventing it from re-entering the atmosphere.

Concrete Examples

• Climeworks' "Mammoth" Plant in Iceland: As the world's largest DACCS facility, Mammoth captures up to 36,000 tons of CO2 per year. The captured CO2 is then mixed with water and injected into deep basalt rock formations, where it mineralizes and turns to stone in a matter of years, representing one of the most permanent forms of carbon storage.
• Corporate Offsetting: A company like Microsoft purchases millions of dollars worth of carbon removal credits from DACCS projects to counteract its historical and residual emissions. This investment not only helps Microsoft advance its net-zero commitments but also provides the critical revenue needed to scale up DACCS technology.

DACCS is a vital technology in the portfolio of climate solutions, offering a pathway to remove legacy carbon emissions. While distinct from the regulated allowances market, the high-quality credits from DACCS play a growing role in the broader carbon markets ecosystem.