CO2 capture technologies
This community is evolving from being just about CDR to include all CO~2~ capture, removal, utilization, sequestration & storage technologies. So let's discuss everything related to:
- Carbon Capture and Storage (CCS)
- Carbon Capture, Utilization, and Storage (CCUS)
- Direct Air Capture (DAC) / Direct Air Carbon Capture and Sequestration (DACCS)
- Carbon Dioxide Removal (CDR) / Greenhouse Gas Removal (GGR)
- etc
While many climate scientists have reservations about CCS, the crisis has now grown so acute that almost all the net zero pathways modeled by the U.N.-backed Intergovernmental Panel on Climate Change (IPCC) and the Paris-based International Energy Agency (IEA) envision huge deployments of the technology by mid-century. Governments have also embraced the prospect that CCS could be a cost-effective means for reducing emissions without disrupting fossil fuel-based economies.[1]
Perhaps, it could be considered alarming that these technologies are often intertwined with fossil fuel companies. These corporations use them as an excuse not to phase out their production, while portraying themselves as part of the solution. (see: Exxon Mobil, BP, Shell, Chevron, TotalEnergies)
Carbon Capture and Storage (CCS), according to the definition by the IPCC, is a process that captures CO~2~ from a point-source.
The terms CCS and Carbon Capture, Utilization, and Storage (CCUS) are closely related and often used interchangeably. Both terms have been used predominantly to refer to Enhanced Oil Recovery (EOR) a process in which captured CO~2~ is injected into partially depleted oil reservoirs in order to extract more oil.
Some sources use the term CCS, CCU, or CCUS more broadly, encompassing methods such as Direct Air Capture (DAC) or Direct Air Carbon Capture and Sequestration (DACCS), as well tree-planting which remove CO~2~ from the air.
Carbon Dioxide Removal (CDR) is defined by the IPCC as: "Anthropogenic activities removing CO~2~ from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products."
Synonyms for CDR include Greenhouse Gas Removal (GGR), negative emissions technology, and carbon removal. The term geoengineering (or climate engineering) is sometimes used in the scientific literature for CDR. The terms geoengineering or climate engineering are no longer used in IPCC reports.
Biochar is such an expanding area of investigation, it would be difficult to write a comprehensive book at this point. Of course the root idea of partial-combustion to make soil amendment is well-enough known, but there is much being learned about how to alter the properties of the char by how the pyrolysis is performed. There is much to be learned about how much char to add and how to pretreat the char. Beside burning to make char, there are other ways it can be heated and those affect the type of pyrolysis products that form - molten salt, steam, and subcritical hot water are all gaining prominence. The management and use of the pyrolysis products aside from the char is also a complex topic.