Carbon Capture and Sequestration

Abstract

 

Previous chapters have discussed techniques for reducing the amount of CO2 and other greenhouse gases that are added to the atmosphere. Although these technologies are helping to mitigate some of the impacts of climate change, they are too little, too late. Unless there is a world-wide and radical shift in our commitment to deploying these technologies at the required speed, we are not going to meet targets provided by organizations such as the IPCC.

 

Therefore we will need to implement “geoengineering” technology, i.e., we will need to make a direct intervention in the Earth’s climate systems in order to bring temperatures down more quickly. There are two types of geoengineering discussed in this book. The first, which is the topic of this chapter, is known as Carbon Capture and Sequestration (CCS). The second type of geoengineering is Solar Radiation Management (SRM). It is described in the next chapter.

 

There are two types of CCS technology: point capture and direct air capture. Both technologies are proven, but commercial applications at present are extremely limited in scope. As with all other greenhouse gas reduction technologies, the level of effort needed to implement CCS at the required level is immense, yet progress to date has been much too limited. A much greater commitment is needed if the Year 2050 goals are to be met.

Contents

Abstract

Background

Status

Natural Carbon Capture / Sequestration

Biological Carbon Capture

Reforestation

Burning Biomass

Ocean Fertilization

Biochar

Carbon Capture Strategies
Direct Air Capture

Point Capture

Post-Combustion

Pre-Combustion

Oxyfuel 

Transportation

Sequestration

Oil Wells

Carbonates

Ocean Storage

Pipelines and Shipping

Biofuels

Ethanol

Algae Biofuels

Synthetic Fuels

Products from CO2

EOR

Petrochemicals

Cement

Commercial Applications

Climeworks

Carbon Engineering

Blue Planet Systems

Economics

Conclusions

Status

Carbon Capture and Sequestration

The sketch shows the two principal forms of non-biological CO2 capture: Direct Air Capture and Point Capture.

There are three ways in which the captured CO2 can be handled. The first way is to recycle it to make biofuels. This approach reduces the amount of fossil fuels that are needed, but it does not create a net reduction in atmospheric CO2. It gives us more time to make a transition to carbon-free energy, but it does not sequester CO2, nor can this approach remove CO2 that is already in the atmosphere. If the CO2 is used for End of Run (EOR) oil extraction then additional fossil fuels are burned.

The second way in which the extracted CO2 can be used is to make petrochemical products. These eventually degrade and decay but, once more, they do provide some breathing room.

The third way of handling the captured CO2 is either to sequester it underground (probably in a depleted oil well) or to convert it into solid carbonate (which is how CO2 is removed from the atmosphere naturally, and hence why there is a picture of the white cliffs of Dover at the head of this post).

All of the processes shown in the sketch have to be powered by energy sources that are not carbon based (solar, wind or nuclear). Otherwise the overall process may wind up emitting more CO2 than is captured.

Point Carbon Capture and Sequestration

The sketch shows three types of Point Capture system. They are post-combustion, pre-combustion and oxyfuels.

 

The post-combustion process captures the CO2 in the flue gas leaving a power plant or industrial facility. Pre-combustion is basically a syngas/hydrogen process that is discussed in Chapter 6 — Hydrogen. The oxyfuel process burns the carbon-based fuel in an oxygen stream. The flue gas contains just water vapor and CO2. Once the water vapor has been condensed, the CO2 can be sent to sequestration without further processing.

All of the processes shown in the sketch have to be powered by energy sources that are not carbon based (solar, wind or nuclear). Otherwise the overall process may wind up emitting more CO2 than is captured.

Assortment of Books

Articles and Blogs

The following articles, blogs and videos provide more information on  the topics discussed in this chapter.

Articles

 

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