What are CCS And CDR Technologies?

Table of Contents

Context: COP28 talks debate CCS and CDR for climate change mitigation. While crucial for the 1.5°C goal, concerns exist about their scale, equity, and potential to mask continued fossil fuel use.

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CCS (Carbon Capture and Storage)

What is CCS?

CCS captures carbon dioxide (CO₂) at the source of emissions before it enters the atmosphere.
This includes sources like fossil fuel power plants and industrial processes like steel and cement production.

How does CCS work?

There are various methods for capturing CO₂, including absorption, adsorption, and membrane separation.
Captured CO₂ is then transported and stored underground in geological formations like depleted oil and gas fields or saline aquifers.

Limitations

Scalability: CCS is still under development and hasn’t been proven effective at large scales.
Cost: CCS is expensive and requires significant investment.
Leakage: There are risks of CO₂ leaking from storage sites, potentially negating the benefits of capture.
Energy needs: CCS requires additional energy to capture, transport, and store CO₂.
Methane emissions: Leakage of methane from upstream oil and gas production can undermine the benefit of CCS.

Role in achieving climate goals

IPCC AR6 report suggests CCS can be used to counterbalance hard-to-abate emissions, but not to justify continued high fossil fuel use.
CCS with high capture rates (90-95%) and permanent storage is crucial.
It shouldn’t replace direct mitigation efforts like reducing fossil fuel reliance.

CDR (Carbon Dioxide Removal)

What is CDR?

CDR removes CO₂ from the atmosphere, either through natural or technological means.
Natural methods:
- Afforestation and reforestation: Planting trees absorb CO₂ through photosynthesis.
- Enhanced weathering: Crushing certain rocks can accelerate natural CO₂ uptake.
Technological methods:
- Direct air capture (DAC): Machines capture CO₂ directly from the air.
- Bioenergy with carbon capture and storage (BECCS): CO₂ from burning biomass is captured and stored.

Limitations

Land requirements: Many CDR methods, like afforestation, require significant land area, raising concerns about equity and competition with other land uses like agriculture.
Scalability: Technological CDR methods are still under development and need to be scaled up significantly.
Cost: CDR can be expensive, and questions remain about who will pay for it at scale.

Role in achieving climate goals

IPCC AR6 report suggests CDR is necessary to achieve the 1.5°C warming limit with no or limited overshoot.
CDR should be used strategically to compensate for hard-to-abate emissions, not to justify continued fossil fuel use.
Research is crucial to determine the viability and scalability of various CDR methods.

Pitfalls

Reliance on CCS and CDR could lead to continued high emissions.
Some CCS applications use captured CO₂ to extract more oil, contradicting its climate benefits.