University of Oxford & Carbon Brief: 10 carbon capture methods compared

"Ten ways to use CO2 and how they compare". A great 2019 article by researchers from University of Oxford published by Carbon Brief.

Conventionally, “CO2 utilisation” is an industrial process that makes an economically valuable product using CO2 at concentrations above atmospheric levels. CO2 is either transformed using chemical reactions into materials, chemicals and fuels, or it is used directly in processes such as enhanced oil recovery (EOR).

The paper categorises the specific 10 pathways of CO2 utilisation in 3 groups, considering how easily the carbon flows around the Earth’s spheres and where it ends up:

• “Open” utilisation pathways that store CO2 in leaky natural systems, such as forests, which can turn from sink to source very quickly

• “Closed” pathways, such as building materials, offer near permanent storage of CO2

• “Cycling” utilisation, such as CO2-based fuels, which moves carbon around over short timescales

This is slightly different way of looking at carbon capture. Recall yesterday's article "CO2 removal solutions: A buyer’s perspective. By McKinsey."

And here are the 10 pathways:

1. CO2 chemicals: catalysts and using chemical reactions to build products, such as methanol, urea (to use as fertiliser) or polymers (for use as durable products in buildings or cars)

2. CO2 fuels: hydrocarbon fuels, including methanol, synfuels, and syngas

3. Microalgae: processing the biomass to make products, such as fuels and high-value chemicals

4. Concrete building materials: CO2 can be used to “cure” cement, or in the manufacture of aggregates

5. CO2-enhanced oil recovery (EOR): Injecting CO2 into oil wells can increase the production of oil ( see Petrobrás article from a few days ago )

6. Bioenergy with carbon capture and storage (BECCS): operator captures CO2 by growing trees, produces electricity through bioenergy and sequesters the resulting emissions

7. Enhanced weathering: crushing rocks, such as basalt, and spreading them on land can result in the accelerated formation of stable carbonate from atmospheric CO2. Enhanced yields on agricultural lands.

8. Forestry: timber from both new and existing forests, product for buildings and displace cement use

9. Soil carbon sequestration: land management techniques for soil carbon sequestration can not only store CO2 in the soil but also enhance agricultural yields

10. Biochar: “pyrolysed” biomass, plant material that has been burnt at high temperatures under low oxygen levels. Application to agricultural soils with potential to increase crop yields

Click below to read more at Carbon Brief, including volumes and cost estimates.