Researchers Propose Ways to Meet IPCC’s Climate Targets

The Intergovernmental Panel on Climate Change (IPCC) has reported that the capture and storage of carbon dioxide (CO₂) underground is one of the major components for keeping global warming below 2 °C above the pre-industrial levels by 2100.

Carbon capture and storage (CCS) would be employed alongside other interventional measures such as energy efficiency, renewable energy, and electrification of the transportation industry.

Models were used by the IPCC to generate around 1,200 technology situations in which climate change targets are fulfilled by using a combination of these interventions, a majority of which demands the use of CCS.

A recent study performed by Imperial College London has suggested that merely 2,700 Gigatonnes (Gt) of CO₂ would be adequate to fulfill the global warming targets outlined by the IPCC. This figure is much less than the leading estimates made by industry and academic teams of what is available, indicating that there is over 10,000 Gt of CO₂ storage space worldwide.

The study also identified that the present speed of growth in the CCS’ deployed capacity is on track to fulfill certain targets outlined in the IPCC reports, and that investigation and commercial efforts should work on sustaining this growth while demarcating sufficient underground space to preserve this much of CO₂ gas.

The findings have been published in Energy & Environmental Science journal.

Capturing Carbon

In the CCS process, CO₂ is trapped at its emission source, such as fossil-fuel power stations, and stored underground to prevent it from escaping into the atmosphere. Along with other climate change mitigation plans, CCS may help the world meet the climate change mitigation objectives outlined by the IPCC. But so far, the amount of the required CO₂ storage has not been particularly measured.

Under the guidance of Dr Christopher Zahasky at the Department of Earth Science and Engineering of Imperial College London, the researchers discovered that globally, the CCS capacity grew by 8.6% in the last two decades, putting the individuals on track to fulfill several climate change mitigation situations that comprise CCS as part of the mix.

Nearly all IPCC pathways to limit warming to 2 °C require tens of Gts of CO₂ stored per year by mid-century. However, until now, we didn’t know if these targets were achievable given historic data, or how these targets related to subsurface storage space requirements.

Dr Christopher Zahasky, Assistant Professor, University of Wisconsin-Madison

Dr Zahasky performed the study at Imperial College London.

He continued, “We found that even the most ambitious scenarios are unlikely to need more than 2,700 Gt of CO₂ storage resource globally, much less than the 10,000 Gt of storage resource that leading reports suggest is possible. Our study shows that if climate change targets are not met by 2100, it won’t be for a lack of carbon capture and storage space.”

Rather than focus our attention on looking at how much storage space is available, we decided for the first time to evaluate how much subsurface storage resource is actually needed, and how quickly it must be developed, to meet climate change mitigation targets.

Dr Samuel Krevor, Study Co-Author, Department of Earth Science and Engineering, Imperial College London

Speed Matters

For the first time, the study has demonstrated that the highest storage space required is just approximately 2,700 Gt; however, this amount will increase if the deployment of CCS is delayed.

The scientists resolved this problem by integrating information on the last two decades of CCS growth, combining data on the historical rates of growth in energy infrastructure, and applying models that are typically used for tracking the depletion of natural resources.

According to scientists, the rate at which CO₂ is preserved is significant to make it effective in climate change mitigation. If CO₂ is stored faster, less total subsurface storage resources would be required to fulfill the storage targets. The reason is it becomes more difficult to locate new reservoirs or make additional use of the already existing reservoirs as they become full.

The scientists discovered that storing sooner and faster than present-day deployment strategies might be required to support the governments to meet the most determined climate change mitigation situations outlined by the IPCC.

The research also indicated that the use of growth models—a standard tool in resource assessment—can help the governments and industry to track long-term resource requirements and short-term CCS deployment progress.

But the scientists also pointed out that fulfilling the CCS storage needs will not be adequate on its own to reach the climate change mitigation targets set out by the IPCC.

Our analysis shows good news for CCS if we keep up with this trajectory—but there are many other factors in mitigating climate change and its catastrophic effects, like using cleaner energy and transport as well as significantly increasing the efficiency of energy use.

Dr Samuel Krevor, Study Co-Author, Department of Earth Science and Engineering, Imperial College London

The study was funded by ACT ELEGANCY, DETEC (CH), BMWi (DE), RVO (NL), Gassnova (NO), BEIS (UK), Gassco, Equinor, and Total, the European Commission under the Horizon 2020 programme, EPSRC, and the UK CCS Research Centre.

Journal Reference:

Zahasky, C & Krevor, S (2020) Global geologic carbon storage requirements of climate change mitigation scenarios. Energy & Environmental Science. doi.org/10.1039/D0EE00674B.