Direct air capture (DAC) is a technology that removes carbon dioxide (CO2) from the atmosphere. DAC systems are considered by many to be simply greenwashing. DAC systems use a variety of methods to capture CO2, including:
- Chemical absorption: A liquid solvent is used to absorb CO2 from the air. The solvent is then heated to release the CO2, which can be stored or used for other purposes.
- Physical adsorption: A solid material is used to adsorb CO2 from the air. The material is then heated to release the CO2, which can be stored or used for other purposes.
- Electrochemical separation: An electrochemical process is used to separate CO2 from the air. The CO2 can then be stored or used for other purposes.
Once CO2 has been captured, it can be stored underground, used to make products such as concrete and fuels, or released back into the atmosphere if it is captured from a source that is already emitting CO2.
Update Aug 2023 – US Funds R&D on DAC
The USA unveiled plans and $1.2b to fund DAC. The U.S. Department of Energy (DOE) announced it will spend $1.2 billion for two pioneering facilities—one in Texas, the other in Louisiana—that will remove millions of tons of carbon dioxide (CO2) annually from the atmosphere using a technology known as direct air capture (DAC). Part of a controversial effort to combat global warming, the awards represent the first phase of $3.5 billion in funding for DAC hubs set aside in last year’s Bipartisan Infrastructure Law and mark the first major governmental backing in the world for the emerging carbon capture technology.
The program aims to create four DAC hubs over the next 10 years, each capable of removing and storing at least 1 million tons of CO2 each year. As part of the program’s rollout, DOE officials also announced funding for an additional 19 conceptual and engineering studies of potential future DAC plants.
Promising Technology or A Scam
DAC is promoted as a promising technology for reducing greenhouse gas emissions. However, it is still in the early stages of development, and the cost of capturing CO2 is still high. As the technology continues to develop, the cost of capturing CO2 is expected to decrease, making DAC a more viable option for reducing greenhouse gas emissions. The key input is the amount of energy needed, and if it were to be low emission it would need to be renewable energy.
Here are some of the benefits of direct air capture:
- It can help to reduce the concentration of CO2 in the atmosphere, which is a major contributor to climate change.
- It can be used to capture CO2 from a variety of sources, including power plants, factories, and vehicles.
- It can be used to produce high-purity CO2 for use in other applications, such as food and beverage production, and the production of synthetic fuels and chemicals.
Here are some of the challenges of direct air capture:
- The technology is still in its early stages of development, and the cost of capturing CO2 is still high.
- The energy required to operate DAC systems can be a significant source of emissions.
- The environmental impact of DAC systems is not fully understood.
Overall, direct air capture is a promising technology for reducing greenhouse gas emissions. However, there are still challenges that need to be addressed before it can be widely deployed.
Shell Oil DAC Example
Energy needed is 100EJ for carbon-sucking machines to absorb more than 5 billion tons of CO2 per year. Shell’s assertion in Bloomberg March 2023
Global temperature rise is less than 1.24C by 2100, after briefly rising above 1.5C in the middle of the century. Another Shell assertion.
To read more Shell greenwashing read this article by Client Earth
IEA Says Carbon Pricing Needed
The primary change to Net Zero by 2050 is reducing emissions, but IEA says some DACs will be needed. IEA says nearly half of the reductions in 2050 in the NZE Scenario come from technologies that today are only at the demonstration or prototype phase
Whereas Prof Mark Jacobson in his book No Miracles Needed says that all of the technologies are already available. Who is right?
The NZE Scenario calls for a substantial scale-up of global CDR.
By 2030, the capacity of DAC‑based technologies (for both CO2 storage and CO2 utilisation) needs to increase from less than 0.01 million tonnes of CO2 a year (MtCO2/year to around 70 MtCO2/year.
By 2050, it would need to be approximately 600 Mt CO2/year. Thats equivalent to the total energy-related CO2 emissions from Indonesia in 2021.