Context:
A study published in Environmental Science & Technology indicates that CCS technologies come with a considerably higher cost compared to transitioning to renewable energy sources.
Carbon Capture and Sequestration (CCS)
- Definition: Captures CO₂ emissions from refineries, power plants, and stores them underground.
- Difference from Carbon Dioxide Removal (CDR):
- CCS: Prevents CO₂ from entering the atmosphere.
- CDR: Removes CO₂ already present in the atmosphere.
Types of Carbon Sequestration:
- Ocean Sequestration: Injecting CO₂ into the deep ocean or fertilizing the ocean with nutrients to enhance biological productivity and carbon uptake.
- Terrestrial Sequestration: Storing carbon in plants, soils, and other terrestrial ecosystems through afforestation, reforestation, and sustainable agricultural practices.
- Geological Sequestration: Injecting CO₂ into deep underground geological formations, such as depleted oil and gas reservoirs or saline aquifers, for long-term storage.
CCS Process:
- Capture: CO₂ captured from power plants and industries like steel and cement.
- Transport: CO₂ compressed into liquid form and transported to underground storage sites.
- Storage: CO₂ injected into deep underground formations like saline aquifers or depleted oil and gas reservoirs.
Capture Techniques:
- Post-combustion: Uses chemical solvents to separate CO₂ after fossil fuel combustion.
- Pre-combustion: Captures CO₂ before combustion by converting fossil fuels into synthetic gas and hydrogen.
- Oxyfuel combustion: Burns fossil fuel with pure oxygen, producing CO₂ and water vapor, which is then separated and captured.
- Most Efficient Method: Oxyfuel combustion, but requires high energy input for oxygen burning.
IPCC AR6 Report Findings on Effectiveness of CCS:
- CDR: Used only for hard-to-abate emissions, not to support continued fossil fuel use.
- CCS: Considered only when capture efficiency is 90-95% or more and emissions are stored permanently.
- Methane leakage: From fossil fuel production must remain below 0.5% (ideally 0.2%) for CCS to be effective.
Carbon Capture, Utilization, and Storage (CCUS) Centres in India:
- National Centre of Excellence in Carbon Capture and Utilization (NCoE-CCU) at IIT Bombay, Mumbai.
- National Centre in Carbon Capture and Utilization (NCCCU) at JNCASR, Bengaluru.
Source: The Hindu
Previous Year Questions
Consider the following activities:
1. Spreading finely ground basalt rock on farmlands extensively
2. Increasing the alkalinity of oceans by adding lime
3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters
How many of the above activities are often considered and discussed for carbon capture and sequestration?
[UPSC CSE – 2023 Prelims]
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (c)
In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration?
1. Abandoned and uneconomic coal seams
2. Depleted oil and gas reservoirs
3. Subterranean deep saline formations
Select the correct answer using the code given below:
[UPSC CSE – 2017 Prelims]
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (d)