The World’s largest facility designed to remove carbon dioxide from the atmosphere started operations in Iceland.
About
It is named Mammoth and it is the second commercial direct air capture (DAC) facility in the nation and is significantly larger than its predecessor, Orca, which began in 2021.
It is situated on a dormant volcano in Iceland and 50 kilometers from an active volcano.
The facility draws in air and chemically extracts captured carbon by turning it into stone beneath the earth’s surface, utilizing Iceland’s abundant geothermal energy to power the process.
It aims to remove 36,000 tons of carbon annually— equivalent to removing about 7,800 gas-powered cars from the road each year.
Direct Air Capture (DAC) Facility
DAC technologies extract CO2 directly from the atmosphere at any location, unlike carbon capture which is generally carried out at the point of emissions, such as a steel plant.
The CO2 can be permanently stored in deep geological formations or used for a variety of applications.
To date, 27 DAC plants have been commissioned in Europe, North America, Japan, and the Middle East capturing almost 0.01 Mt CO2/year.
Concerns of Direct Air Capture (DAC) Facility
Energy Requirements: DAC facilities require significant amounts of energy to operate, which could potentially exacerbate rather than alleviate carbon emissions if the energy source is not renewable or low-carbon.
Cost: Building and operating DAC facilities is expensive, especially at scale.
Scalability: While DAC technology shows promise, its scalability remains uncertain.
It’s unclear whether DAC can be scaled up sufficiently to make a meaningful impact on global carbon dioxide levels and climate change mitigation efforts.
Diversion from Natural Solutions: Some argue that investing in DAC technology may divert attention and resources away from natural climate solutions like reforestation.
Carbon Capture Technologies
The technologies can be broadly categorized into three main types: pre-combustion capture, post-combustion capture, and oxyfuel combustion.
Pre-Combustion Capture:
Gasification: Involves converting carbon-containing feedstock, such as coal or biomass, into a synthesis gas (syngas) composed primarily of carbon monoxide (CO) and hydrogen (H2). The CO2 can then be separated from the syngas before combustion.
Chemical Looping Gasification: Utilizes metal oxide particles to indirectly convert carbon-containing fuel into syngas. The metal oxide captures the carbon from the fuel, and then the CO2 can be separated from the metal oxide.
Integrated Gasification Combined Cycle (IGCC): Integrates gasification technology with a combined cycle power plant, allowing for efficient power generation while capturing CO2 before combustion.
Post-Combustion Capture:
Amine Scrubbing: Involves passing the flue gas from combustion through a liquid solvent, typically an amine solution, which absorbs CO2. The CO2-rich solvent is then heated to release the captured CO2 for storage or utilization.
Membrane Separation: Uses selective membranes to separate CO2 from other gases in the flue gas based on differences in permeability. Adsorption: Utilizes solid materials, such as activated carbon or zeolites, to adsorb CO2 from the flue gas. The adsorbent is then regenerated by desorbing the CO2, allowing for multiple cycles of capture and release.
Oxy-Fuel Combustion:
Involves burning fossil fuels in oxygen instead of air to produce a flue gas consisting mainly of CO2 and water vapor.
The CO2 can then be easily separated from the water vapor and other impurities, resulting in a concentrated stream of CO2 for storage or utilization.
Emerging DAC technologies
Electroswing adsorption (ESA)-DAC is based on an electrochemical cell where a solid electrode absorbs CO2 when negatively charged and releases it when a positive charge is applied.
It is currently being developed in the United States and the United Kingdom.
Zeolites are now being adopted for DAC due to their porous structure suitable for CO2 adsorption.
The first operational DAC plant relying on zeolites was commissioned in 2022 in Norway, with plans to scale the technology up to 2,000 tCO2/year by 2025.
Passive DAC relies on accelerating the natural process that transforms calcium hydroxide and atmospheric CO2 into limestone.
This process is being engineered in the United States by a company using renewably powered kilns to separate CO2 from limestone.
Way Ahead
Current global carbon removal efforts are capable of handling only about 0.01 million metric tons per year, far from the 70 million tons per year by 2030 to meet climate targets.
With larger DAC plants under construction and more ambitious plans for future facilities, there is hope that significant progress can be made in combating climate change.
Innovation in CO2 use opportunities, including synthetic fuels, could drive down costs and provide a market for DAC.
Early commercial efforts to develop synthetic aviation fuels using air-captured CO2 and hydrogen have started, reflecting the important role that these fuels could play in the sector.
