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How Singapore can tap carbon capture technology to fight climate change post-Covid-19

Carbon dioxide (CO2) is largely considered the main culprit for global warming and the climate change patterns we see happening around the world.

How Singapore can tap carbon capture technology to fight climate change post-Covid-19

A view of an oil refinery off the coast of Singapore.

Carbon dioxide (CO2) is largely considered the main culprit for global warming and the climate change patterns we see happening around the world. 

According to the International Energy Agency, the current global CO2 emissions released into the atmosphere are about 36 billion metric tonnes and expected to rise to 40 billion metric tonnes by 2040.

According to a report published by leading science journal Nature in May, circuit breakers and other unprecedented lockdowns worldwide due to the Covid-19 pandemic have reduced daily global CO2 emissions by 17 per cent, compared to the mean 2019 levels of the same period.

But as Singapore and other nations begin to ease restrictions and progressively resume activities,  the critical question is whether the decrease in carbon emissions seen in recent months will prove to be short-lived.

Whether our post-pandemic rebound will restore CO2 emissions to their initial, unabated increase will depend heavily on government action, economic incentives and the use of innovative technology to mitigate the effects of atmospheric greenhouse gases.

PROMISING TECHNOLOGY

A technology that has shown great potential in reducing the carbon footprint in a significant way is carbon capture and storage (CCS).

It is a method of capturing CO2 mainly from the source of emission, such as from power plants and industrial process effluents, before they escape into the atmosphere. 

The captured CO2 is then permanently stored safely in carefully selected geological storage sites, such as underground rock formations or depleted oil and gas reservoirs, or in saline aquifers or oceanic sequestration.

The safely stored captured CO2 can be repurposed to produce value added chemicals and other mineralisation products for landfills and the construction industry. Thus, CCS is often also referred to as CCS/U to include its utilisation aspects.

As agreed by United Nations member parties in the Paris agreement signed in 2015, CCS/U will be a crucial approach to limit the increase in global temperatures to 2°C above pre-industrial temperatures.

However, more monetary incentives, policies that fully support investments in CCS and CCS/U, as well as meaningful industry collaboration, will be needed in order to fully realise the potential of this technology in a post-pandemic world.

CHALLENGES AND OPPORTUNITIES 

The Carbon Pricing Act came into effect in Singapore in January 2019, under which, any industrial entity that emits greenhouse gases equal to or above 25,000 tonnes of CO2 annually should submit a monitoring plan and emissions report every year and will be subjected to carbon tax.

About 84 per cent of CO2 emissions in Singapore are from stationary sources, with the majority coming from power generation that uses natural gas as feedstock. Natural gas is the cleanest burning fossil fuel as it produces much less CO2 emissions compared to coal-based power plants.

Specifically, electricity generated from natural gas produces a low CO2 exhaust of about 3 to 5 per cent.

However, attempting to capture the CO2 from such low concentration exhaust streams is challenging.

The lower the starting composition, the higher the energy penalties levied in the application of CCS/U technology.  

The application of CCS/U technology requires a substantial amount of work — from separating CO2 from the other gases in a power plant's exhaust, to concentrating it and compressing it into a continuous stream for transportation, storage and utilisation. 

Inevitably, the process consumes a significant amount of energy and reduces the electrical output from a power plant. This drop in the energy efficiency of the power plant due to carbon capture efforts is known as the energy penalty.

This is partly why no power plant in Singapore has a retrofitted  CO2 capture system.

Singapore’s challenge in advancing CCS/U lies in lowering the energy penalty to capture CO2 for storage and utilisation at a lower cost.

This may require the development of new technologies or significant improvements to existing methods to develop CCS/U solutions tailored to our unique power sector in Singapore.

Moving forward, a close partnership between industry and academia is crucial to generate impactful innovations and to develop practical solutions in the CCS/U technology landscape in Singapore.

The creation of the Singapore Energy Centre (SgEC) with ExxonMobil as its founding partner in 2018 was a step in the right direction. This was ExxonMobil’s first such research and development partnership outside the United States.

At the National University of Singapore (NUS), experts from different domains — such as material science, chemistry and engineering — are working together to develop efficient, reliable, cost-effective, and environmentally benign technologies for CCS/U.

REALISING THE PROMISE OF TECHNOLOGY 

At present, my team from NUS Department of Chemical and Biomolecular Engineering is developing a CO2 capture technology based on gas hydrates. Gas hydrates are crystalline ice-like compounds mainly composed of water that can capture and store small gas molecules like CO2.

It is estimated that 1-unit volume of gas hydrates can capture/store up to 184-unit volumes of CO2 in its gaseous form at atmospheric standard conditions, with water being used as a benign solvent to capture CO2.  

In other words, instead of using chemicals and traditionally more expensive materials in the capture of CO2, the technology behind gas hydrates is using water to capture the CO2, which could result in higher cost savings.

With innovations in process design, we are working towards further improving the process efficiency, reducing the energy consumption and scaling up the process for industry adoption.

In collaboration with ExxonMobil, my team is also developing and testing a laboratory-scale prototype that can mimic the deep ocean environment, to investigate the stability of CO2 hydrates for potential long-term storage of CO2 in deep oceanic sediments.

Nature has always provided us the cue to develop long-term solutions, and naturally-formed deep oceanic sediments have been storing methane in the form of methane hydrates for millions of years and they have been stable for such a duration.

If we can mimic what Mother Nature has modelled for us, we can develop a safe and likewise stable method for CO2 storage in the long run.

This is one of several CCS/U related R&D projects under the SgEC which includes novel carbon capture materials and processes, as well as a study of regional subsurface sequestration opportunities.

Although Covid-19 has dominated our priorities in recent months, it holds a key lesson in that early investments in pandemic control and prevention had long-term payoffs, which were only manifested at the height of this crisis.

Likewise, the issue of global warming is no different — it is one that we cannot put on hold, and research must continue now to uncover new and innovative ways to reduce CO2 emissions.

As Singapore begins its road to post-pandemic recovery, our resolve to tackle the looming climate change crisis should only be strengthened.

 

ABOUT THE AUTHOR:

Praveen Linga  is Dean’s Chair Associate Professor at the Department of Chemical and Biomolecular Engineering, National University of Singapore.

Related topics

global warming climate change carbon emissions carbon capture

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