Sending a rocket up into the atmosphere to vacuum up excess carbon dioxide and reverse climate change may seem like a fantasy at this point.
However, carbon capture technologies actually do exist and have been in use in the oil and gas industry — albeit in a less sci-fi-like capacity — for years. But it is only recently that the technology has been put forward as a solution to tackle the climate crisis.
Many countries and companies have included carbon capture technology in their stable of tools to reach their net zero emissions goals. This includes the capture of carbon dioxide from power plants, industrial processes and even directly from the atmosphere.
The International Energy Agency (IEA) has taken to calling carbon capture, utilisation and storage (CCUS) one of the four key pillars of the global energy transition, alongside renewable energy-driven electrification, bioenergy and hydrogen.
Mohamed Kheireddine Aroua, professor and head of Sunway University’s Research Centre for Carbon Dioxide Capture and Utilisation, saw his career evolve with this trend. He moved to Malaysia in 1993 and became a visiting lecturer at Universiti Malaya, focusing on carbon dioxide removal from natural gas and petrochemical processes.
“After 20 years, I became a senior lecturer but my dream was to set up my own research centre and expand the use of carbon capture technology to address a problem facing humanity,” says Mohamed Kheireddine. His dream came true in 2017 when Sunway University invited him to set up the research centre devoted to carbon capture.
His research focuses on developing absorbent solvents (liquid) from renewable sources and adsorbents (solid) from waste biomass to capture carbon dioxide from point sources, which could be power plants, and from the atmosphere.
What happens after the carbon dioxide is captured is also a focal point for Mohamed Kheireddine, who believes it should be turned into useful raw materials.
His research centre is currently collaborating with Massachusetts Institute of Technology (MIT) on a three-year project to do exactly that. The Malaysian team is in charge of developing the carbon capture technology, while MIT will turn the captured carbon dioxide into raw materials for energy storage devices and useful chemicals.
To Mohamed Kheireddine, this kind of research that creates applications for the captured carbon dioxide will make the technology more feasible. Currently, the costs are prohibitive, which is why adoption of carbon capture technology is low globally. If the carbon dioxide can be sold to industries, it would create a revenue stream for operators of the technology.
“You can say that the technology is established but it’s not ready [to be deployed] because the cost is high, especially to capture carbon from the atmosphere. This is one of the biggest challenges currently and where the US and other countries are investing in,” says Mohamed Kheireddine.
At the moment, there are only 21 CCUS facilities in the world, according to the IEA. The majority of the facilities capture carbon dioxide from natural gas processing and sell the gas to oil companies, which inject it into oilfields to extract additional oil. But when the oil is burned, it releases carbon dioxide into the atmosphere, which negates the positive effects of carbon capture.
The big challenge
The IEA report provides a few more reasons for the slow adoption of carbon capture technology. Many planned projects did not progress due to a lack of consistent policy support. The high cost of installation did not make commercial sense and the public was resistant to underground storage of carbon dioxide.
There were also technical challenges. For starters, the concentration of carbon dioxide varies under different conditions. It is usually about 0.04% in the atmosphere but can reach over 20% in certain natural gas fields. Flue gas from coal and natural gas power plants can contain up to 14% and 10% of carbon dioxide respectively, says Mohamed Kheireddine.
All these require the technology to be modified. Additionally, “flue gas from the chimney is over 100°C. But the amine process captures carbon dioxide most effectively at 30°C to 50°C. This means the gas has to be cooled down before it can be captured, which adds to the cost”, he explains.
Another challenge is the energy required in the process. The solvent has to be heated to release the captured carbon dioxide. Ideally, this heat should be generated from renewable sources instead of conventional fossil fuels.
Ultimately, the high cost of the process is a huge hindrance. It is expensive and does not generate returns, so industry players are not keen to adopt it, observes Mohamed Kheireddine.
Adding to that, capturing carbon dioxide from the atmosphere is a relatively new idea. “It is technologically possible but the cost is still high, exceeding US$100 per ton of captured carbon dioxide,” he says.
But he believes that as the technology is developed further and the captured carbon dioxide is turned into useful raw materials for industries, it will become more economical.
MIT’s project is an example of this. Another possibility is to use the captured carbon dioxide to produce low-carbon hydrogen. On the fun side, the NRG COSIA Carbon XPRIZE had its participants turning carbon dioxide emissions into vodka, hand sanitisers and toothpaste, among other things.
A controversial or relevant solution?
At the moment, the idea of using carbon capture to mitigate climate change has its fair share of detractors, who see this as a diversion from the important work of cutting down carbon emissions in the first place.
Additionally, given the economic and technical challenges, it may not be feasible in time to stop climate change. Using captured carbon dioxide to extract more fossil fuels also doesn’t contribute to climate change mitigation.
Mohamed Kheireddine acknowledges these criticisms. But he believes that given the scale of the problem, a diverse suite of solutions is needed. The transition to renewable energy is still ongoing and there are many industries that will have difficulty adapting.
“Transitioning to renewable energy is a good solution but we need a diverse plan to tackle climate change. Even forest fires, which are happening everywhere now, unleash huge amounts of carbon into the atmosphere. Even with 100% renewable energy powering our electricity, we will still need carbon capture technologies,” he says.
As an oil and gas producing nation, Malaysia seems well poised to explore this technology. Petroliam Nasional Bhd (Petronas) has already stated its intention to do so.
“This is a very strategic opportunity for the country because we can become the leader and tech provider. For Petronas, this is important because natural gas will remain in use for a long time [in our energy portfolio] and we need more efficient technologies to remove carbon dioxide from natural gas,” says Mohamed Kheireddine.
The momentum is strong globally. The UK government pledged to invest £1 billion in CCUS in 2020, while the US government unleashed US$24 million in funding for nine research projects on carbon capture and direct air capture in August.
Meanwhile, the IEA observes that over 30 new plans for integrated CCUS facilities have been announced since 2017. Several of these plants are aiming to install the technology in coal- and gas-fired power plants and cement production. Instead of selling the captured carbon dioxide to oil companies, they are developing industrial hubs to store carbon dioxide.
How it works
The main technology for carbon capture utilises liquid solvents to absorb carbon dioxide. The acidic gas dissolves in the liquid and reacts with amines, an organic compound, to form carbonate, explains Mohamed Kheireddine Aroua, professor and head of Sunway University’s Research Centre for Carbon Dioxide Capture and Utilisation.
This reaction can be reversed so the carbon dioxide is released and the solvent reused. Other versions of this technology use solids instead of liquid solvents to absorb carbon dioxide.
Utilising carbon capture technology at large point sources of carbon dioxide seems like a no-brainer, at least until these sources can be eliminated altogether. Coal-fired power plants account for almost one-third of global carbon dioxide emissions in 2019, according to the International Energy Agency. Carbon-intensive industries such as cement, iron and steel could use the technology as a stopgap measure until they find better alternatives.
Technically, carbon capture and storage can capture up to 95% of all carbon dioxide produced, according to the Climate Technology Centre and Network. But net emissions decline to 90% when the energy required to power the carbon capture process is taken into consideration.
In cases where carbon capture technology is used, the gas is usually compressed and transported to be injected into deep geological formations, where it will be stored permanently. In some cases, the gas is sold to oil companies that inject it into developed oilfields to extract additional oil. Researchers are now working to turn the captured carbon dioxide into useful materials.