What are DAC and CCUS and how can they combat climate change?
March 15, 2023
The reality of climate change – extreme weather, droughts and food shortages – is affecting billions of people globally sparking environmentally conscious initiatives, from recycling to saving energy and driving electric vehicles.
But why does it feel like the prognosis for our planet is not improving?
Because at the current rate of CO2 emission, these actions play a small role versus the damage caused by emissions. At the present rate of burn, we are heading towards more than a 2-degree global increase in temperature – one that will have cascading effects on the planet, its sea levels, and overall habitability.
On top of this, legacy emissions also need to be considered as part of the equation. In an imaginary scenario, where our society stopped all emission-producing activities, the past emissions we released into the atmosphere would continue to impact Earth’s climate. The reason being that CO2 remains in the atmosphere for hundreds of years. Not only do we need to reduce today’s CO2 emissions, but we need to employ solutions that counter legacy or past emissions.
So what can we do to improve our planet’s prognosis?
Two emerging technologies, Direct Air Capture (DAC) and Carbon Capture, Utilization and Storage (CCUS) are at the forefront of CO2 removal and reduction action. What are they? Are they similar or different? And what is their impact in the fight against climate change?
What is Carbon Capture Utilization and Storage?
Carbon capture utilization and storage (CCUS) (IEA, “About CCUS – Analysis”) is a catch-all term for two types of solutions: Carbon Capture and Utilization (CCU), focused on capturing carbon from the atmosphere (the air we breathe) or fossil fuel based point source carbon capture and making use of it in various industrial processes like food production, indoor farming, or chemical production. And Carbon Capture and Storage (CCS), set on sequestering carbon and permanently removing it from the atmosphere, including deep underground storage.
Carbon capture, storage and utilization make up the three aspects of CCUS
‘Capturing’ CO2 means to selectively separate it from a different gas mixture where it is already present either at industrial plants or from the air around us.
Utilization refers to the reality that CO2 is needed as a resource in many important areas of the economy. By recycling CO2 in a circular supply chain model, we can extract and reuse the CO2 already in the atmosphere and utilize it where it is needed.
Storage of CO2 is the permanent removal of CO2 from our atmosphere – the CO2 that is captured will never make its way back into our air for many years to come.
Carbon capture utilization and storage essentially uses carbon capture technology to tackle and reduce the point source emissions that enter the atmosphere from high-emitting industry operations like oil refineries and fertilizer plants. And when CO2 is captured directly from the ambient air around us, this is where DAC technologies come into play.
What is Direct Air Capture?
Direct air capture (DAC) is considered by global energy experts as an important technological solution to combat climate change. DAC technology uses an advanced air filtration system to separate and capture CO2 directly from the ambient air all around us. As a carbon capture technology, it forms part of the solution for Carbon Capture and Utilization, and Carbon Capture and Storage. So by employing this unique capture technology this reduces the atmospheric concentrations of CO2 almost instantly.
When scaling this technology up and pairing it with storage and utilization, it could accomplish CO2 reductions of between 0.5 and 5 billion tons per year, which when carried out at a critical size and volume, would effectively begin to help cool down the planet, and improve global inhabitability.
Key Facts About DAC
Direct air capture technology removes carbon dioxide that is already in the atmosphere
DAC combined with CCS is sometimes referred to as a carbon removal or allows for negative emissions technology (Lebling, Katie, et al.)
Carbon dioxide is a valuable and necessary resource. With DAC, the CO2 that is removed from the air can be recycled and used as a feedstock for a range of products in building materials like concrete and bricks, and agriculture industries that need a source of carbon to stimulate the yield of crops. Today DAC is sometimes perceived as being too expensive and energy intensive. But we are only at the beginning of the DAC innovation curve. The next generation of DAC technology is set to be more energy and cost efficient, similar to other clean technology efficiency trajectories like solar.
Unlike DAC, Point Source Capture separates CO2 from a gas mixture containing harmful levels of CO2, like the high concentration found in industrial processes using fossil fuel combustion as a source of energy. To stop the increase in CO2 levels, it needs to be captured before it reaches our air, cleaned from toxic gasses, liquified and transported to where it’s needed, which is both expensive and energy intensive. This is achieved with Point Source Capture. DAC however is focused on the emissions already in the air from prior decades and generates and delivers it at the location where it’s needed, avoiding transportation.
So how will carbon capture technologies help us reach responsible emissions levels?
Energy transition scenarios developed by the International Energy Agency indicate both CCUS and DAC will play a part in the journey to carbon neutrality.
While we transition to a renewable energy supply, CCUS will be especially important to compensate for emissions in sectors that are hard to decarbonize or are prohibitively expensive; this is particularly true for fossil fuel industries as well as heavy industry and fertilizer plants. Carbon storage leads to permanent removal of the CO2 from the atmosphere, whereas utilization paves the way to carbon circularity by using CO2 as feedstock. DAC also helps to avoid emissions associated with long-distance transport, as well as removing historical emissions, and therefore restoring atmospheric carbon concentration balance.
The IEA Net Zero Emissions by 2050 Scenario (IEA, “Direct Air Capture 2022”) outlines that DAC will capture more than 85 Mt of CO2 in 2030 growing to 980 MtCO2 in 2050. The route to this figure requires exploration of challenges and opportunities around evolving technologies, their current status and future growth potential.
The future of Decentralized Direct Air Capture (DDAC)
Carbon capture technologies are still in their early stages of development. As the technology emerges, the first versions that are being brought to market are large centralized units that suck in vast amounts of CO2 and profit from selling carbon credits on the voluntary market or substantial government subsidies. These installations are costly to build, run, and take significant time to deploy and can only be installed in certain locations.
At Skytree, we have developed a fully modular and decentralized technology to capture CO2 out of the ambient air via filters with CO2 absorbing sorbent. Then, through a trigger mechanism, the captured CO2 can be efficiently released using smart carbon controls. By positioning DAC at the sites where the CO2 is needed for various industries, the CO2 can be delivered as a feedstock to their operations, at the desired quantity and desired time.
Instead of buying fossil fuel based CO2, often trucked to where it is needed, Skytree DDAC solutions are compact enough to be installed on-site, and modular to scale-up to capture as much CO2 as the facility needs. This effectively creates an on-demand supply of CO2 for a wide range of industries and inturn helps businesses reach carbon neutrality.
Decentralized Direct Air Capture is
Onsite CO2 generation from ambient air
Fully modular with the option to scale up to meet the demand to be used everywhere
A reliable and low energy supply of CO2 for industries like indoor agriculture, food industry, and building material manufacture
DDAC, combined with other CCUS technologies offers a tangible solution to store, remove, utilize and provide a source of carbon that aligns with the goals of a clean circular economy.
Lebling, Katie, et al. “6 Things to Know about Direct Air Capture.” World Resources Institute, 2 May 2022, https://www.wri.org/insights/direct-air-capture-resource-considerations-and-costs-carbon-removal.
IEA. “Direct Air Capture 2022.” IEA, Apr. 2022, https://www.iea.org/reports/direct-air-capture-2022.
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