The global climatic conditions are deteriorating with every passing day. No statistics could possibly describe the severity of the damage that has been incurred by the environment due to anthropogenic activities. There are various contenders for global climate changes, of which, greenhouse gases are the key players. Greenhouse gases are the ones responsible for trapping excess solar energy and increasing the global temperature by 1.20 C over the last few decades. Carbon dioxide (CO2) is the most abundant greenhouse gas in the atmosphere. The amount of (CO2) in the atmosphere is 441parts per million. Apart from the obvious effect of global warming, the increased amount of CO2 in the atmosphereis accelerating ocean acidification and degrading the air quality. The most common source of CO2 emission is the burning of fossil fuels. Other reasons include the burning of biological/ organic material such as wood, oil, gas, solid waste, etc.
On account of the ill effects of fossil fuel-based energy, many nations are shifting to clean and renewable fuels. However, this shift poses numerous challenges at an economic, infrastructural, and social level. Fossil fuels are still the most abundantly used sources of energy. Therefore, we need technologies that will help to curb atmospheric CO2 levels. Carbon capture, storage, and utilisation (CCSU) is one such technology that helps in reducing atmospheric CO2 levels and is emerging as an important technology in climate mitigation.
What is carbon capture, storage and utilisation technology?
The CCSU is a multi-tier process that helps in the capture, transport, storage, and reuse of atmospheric CO2. This technique helps in trapping the CO2 generated in petroleum, steel, aluminium, cement industries, etc. The first plant to capture CO2, was built in 1972, in Texas. Subsequently, many CCSU units have been installed globally. At present, there are 26 CCSU facilities functional across the globe that are responsible for capturing around 36-40 metric tonnes of carbon each year.
Carbon dioxide capture in the CCSU is done using techniques like post-combustion capture, pre-combustion capture, or Oxy-fuel combustion. Each technique has its own set of advantages and disadvantages depending upon its employability. Out of the three techniques, oxy-combustion is said to have a ‘zero emission cycle’. Once captured, CO2 is then purified using a combination of physical and chemical separation techniques. The purified CO2 is then transported under high pressure using a network of pipelines. The captured CO2 is stored in artificial facilities or geological formations such as depleted oil reservoirs, coal seams, basaltic rocks, sedimentary basins, and saline aquifers. The natural reservoirs for carbon (carbon sinks) are forests and oceans.
All of this makes CCSU sound like a perfect technology for climate action, but there are some major concerns in its large-scale adoption and implementation. The major concern is what to do with the captured CO2. Carbon dioxide, as a product, does not have much value whereas, the cost incurred in its capturing, storage, and transport is quite high. The processes involved in CCSU are quite energy intensive and bear a huge energy penalty. Among the other drawbacks, there is also a concern about the leakage of stored CO2. And above all, the important concern raised by environmental activists is the use of captured CO2 in enhanced oil recovery (EOR), which encourages the use of fossil fuel-based energy. Therefore, the activists claim that CCSU is just a policy to justify the use of fossil fuels.
Despite the listed drawbacks, we still need CCSU. As per the United Nations’ report, the elimination of CCSU from climate action will increase the cost of achieving climate stabilisation by 70%. Thus, CCSU has been included under the Clean Development Mechanism (CDM). The aim now is to make the technology as clean and cost-effective as possible and use the captured CO2 to yield a high-value product.
How can we make carbon capture, storage and utilisation clean and cost-effective?
To make CCSU beneficial for climate action, the following criteria should be met. The CCSU unit should be powered using a renewable source of energy, achieving global decarbonisation, large-scale implementation that will work quickly to reverse climate change, and provide a permanent solution to the problem of atmospheric CO2 accumulation.
The solution lies in working on the principle of circular economy, i.e converting carbon dioxide into a valuable feedstock. The captured CO2 can be put to good use in the manufacturing of products such as polymers, construction material, curing of cement, CO2 and hydrogen fuels etc. Moreover, we can use cleaner methods for carbon sequestration such as the use of CO2 fixation by microalgae, enhanced weathering, soil carbon sequestration, biochar, etc. Combining advanced technologies with nature-based solutions will help us make CCSU clean and sustainable. Another recommended approach is to emphasise on carbon capture and utilisation (CCU) rather than storing it for the long term. This will help deal with the problem of leakage. The captured CO2 can be made readily available to fertilisers, food, aircraft, and automobile industries that require CO2 for their product manufacturing processes.
Where does India stand in the use of CCSU?
India, being a densely populated country, faces the major challenge of meeting its energy demands. On account of this, India has high carbon footprints and ranks third in the emission of greenhouse gases. The CCSU is an ideal solution to accelerate our climate actions. At present, India does not have a commercial CCSU unit, but under the Paris agreement, India has established two centres for carbon capture and utilisation at IIT, Bombay and JNCASR, Bengaluru. India has a huge potential for carbon storage, owing to its geological features for carbon sequestration, but we do not have the infrastructural facilities for the same. The government of India is encouraging CCSU technology using an incentive-based approach. Moreover, the government funding agencies are promoting the research and development of cost-effective and clean CCSU technology via its funding programmes. The successful implementation of CCSU in India will come from the collaborative efforts of research institutes and the industrial sector. We are moving forward in this direction with many institutes focusing on carbon capture research and industries trying to use environmentally friendly practices. The adoption of CCSU technology will help India in its climate action as well as accelerate our economy in a sustained manner.