Explained: What is carbon capture, the possible solution to reining in climate change?

By Aditya Mani

It is an almost undisputed claim that one of the biggest threats looming over humanity is climate change. We have all heard about it from our friends, we have all read about it in various fora on the internet and in the news. But how many of us really think about it? How many of us see red when Delhi suffers from smog created by the annual stubble burning in Haryana? How many of us really wonder about the real reasons for the near-annual natural calamitous floods in India? How many of us even think twice before taking the car out for a distance that can be easily covered on foot? A lot of what we do as individuals, as a society, and as an economy contributes to the worsening climatic conditions. In the next few minutes, let’s try to answer a few basic questions about climate change and understand one of the most promising ways to battle it.

What is causing climate change?

The earth has an atmosphere composed of nitrogen, oxygen, hydrogen, carbon dioxide (CO₂), and a host of other gases. Among many others, an important function that the atmosphere performs is to trap some of the heat that is received from the sun. Without this function, the earth would be a cold planet because it would reflect back all of sun’s heat. This is known as the greenhouse effect. Over billions of years of the earth’s existence, the climatic conditions have changed constantly to finally arrive at a perfect proportion of all the gases to contain heat in the right amount that supports life. CO₂, though small in proportion, does a really good job of trapping heat on earth.

Most human activities require energy sources that emit CO₂ into the atmosphere. Because the amount of CO₂ in the atmosphere has been steadily increasing, the amount of heat getting trapped is also increasing. This is affecting nature’s fine balance and causing widespread effects in climatic and geological conditions around the world. Some of these symptoms are global warming, rise in sea levels, extinction of species, and even catastrophic natural calamities. This, in a nutshell, is climate change. This set of phenomena has scientists and governments all over the world worried about humanity’s future.

Why do we produce so much CO₂?

Everything we do requires some form of energy. We require electricity to run our houses and our factories. We require fuel to generate electricity. We require fuel to run our cars, buses, trains and airplanes. At the end of the day, most of our energy needs come from burning fossil fuels. Burning fossil fuels generates a high amount of CO₂ which is eventually released into the air. CO₂ is generally absorbed by trees and the oceans to balance the CO₂ in the atmosphere. This is called the carbon cycle. However, due to deforestation and the consequent reduction in CO₂ absorbing flora, and an unprecedented increase in CO₂ producing human activities, we are witnessing escalated greenhouse effect. Some of the biggest contributors are transportation, electricity and industry. As these are essential components of our economy, and we do not have viable “green” alternatives, we are set on a path for destruction unless we change our ways.

What was the Paris Agreement of 2015?

One big milestone in our attempt to combat climate change was the Paris Accord of 2015. In a landmark agreement, 175 countries agreed upon certain restrictions on their own carbon emissions to ensure that the earth’s temperature did not increase by 2 degree Celsius over pre-industrial levels by the end of the century. In fact, all attempts were promised to be made to curtail the increase to 1.5 degree Celsius. This means that if the average temperature in your city had been 23 degree Celsius in early 1900s, your national government would try to ensure that it remained below 24.5 degree Celsius, or a maximum of 25 degree Celsius by 2100.

However, since then this ambitious goal has looked more and more unlikely. For one, the US, which has one of the largest carbon footprints, has backed out of the Paris accord. Secondly, a recent report by the Intergovernmental Panel on Climate Change (IPCC) says it is very likely that we will cross the 1.5 degree mark as early as 2040. These developments pose new threats to our existence. OPEC’s recent projections state that the demand for oil worldwide will keep increasing till at least 2040. If we are expected to keep emitting CO₂ till more than 20 years from now, the only way to sustain the same living conditions on earth is to somehow remove all this CO₂ from our atmosphere.

Is carbon capture the solution?

It seems theoretically simple. If the high amounts of CO₂ in the atmosphere is the problem, we must find ways to remove this CO₂ as soon as possible. Fortunately for us, such a technology exists, and is already in use in various plants around the world. This technology is called Carbon Capture and Sequestration (CCS). In essence, the idea is to suck out CO₂ either directly from the air, or from the emission source in factories and power plants, and store it in a place where it will either be locked away for a long time, or be used for other purposes. Mass deployment of such CCS facilities will help create negative-emissions’ factories, and eventually help bring the net emissions of the entire world below zero. According to a study by the National Academies of Sciences, Engineering, and Medicine, we need to achieve negative emissions by 2090 to be able to even stick to our 2 degree Celsius goal. The bottom line is that without technologies that help remove CO₂ from the air, we will not be able to achieve this goal.

What is carbon capture? How does it work?

Carbon capture consists of 3 main stages — capture, transportation, and sequestration. Capture of CO₂ happens mostly at sources of emission like power plants, or cement factories. At this stage, CO₂ is separated from the other gases. The other gases are then safely released into the atmosphere, and CO₂ is compressed for transportation. Because CO₂ cannot be dumped at the location of emission, it has to be transported to such locations via special pipelines. At the point of storage, CO₂ is pumped back into the earth for various reasons. You can read more about carbon sequestration here.

Some of the other things that can be done instead of storing carbon inside the earth is to make products out of it such as additives for chicken and fish fodder, and mattresses and foams. The major takeaway from the process of carbon capture is that it enables facilities with large carbon footprints to actually become negative emission facilities by sequestering more CO₂ than they produce.

What is the current state of carbon capture technology?

Already, there are a few CCS installations across the world. Currently, we have about 18 active large scale CCS facilities and 25 more under construction that are expected to be completed 2028. Some oil and gas companies, such as Petra Nova, have taken advantage of the fact that pumping CO₂ into oil basins increases oil productivity. A CCS facility in Iceland has successfully turned massive amounts of CO₂ into stone ensuring that the CO₂ is locked away into the earth for a long time. However, we need many more of such facilities to be able to live up to our 2 degree Celsius goal.

As discussed earlier, we need to go carbon negative no later than 2090 globally. Since we produce almost 40 trillion kilograms of CO₂ each year today, and each CCS facility today captures anywhere between a few hundred to a few million tons of CO₂, we have a long way to go in perfecting this technology and in installing many more facilities worldwide. This will not be possible without sufficient funding, and conducive policies by the governments of the world.

Some studies have also made economic arguments against CCS. A study by the World Economic Forum has shown that fuel costs doubled when CO₂ capture facilities were installed. A faction of environmental activists argued that such carbon capture plants would make the heavy carbon emitters complacent in an age where fossil fuel usage must be kept at a minimum. However, it is important to know that any cost incurred in installation of such carbon capture plants would be minuscule compared to the costs of delaying such positive action.

Is carbon capture really the silver bullet that will remedy climate change?

The jury is still out on that. Today, multiple research agencies have credited carbon capture with the most potential of reining in climate change. But there are significant roadblocks such as the trade-off between immediate costs and future benefits that need to be weighed by industrialists and governments alike. Until these are resolved, we continue to live in the grave danger of irreversibly changing our climate in the next few years.

Aditya Mani is a writing analyst at Qrius