National policy developments and Cabinet endorsement of a geological carbon capture and storage (CCS) roadmap in South Africa can be viewed as major advances for CCS in the country. But scientists say that significant research and prospecting must still be completed before a comprehensive assessment of the technology’s applicability to South Africa can be made.
“While there is significant theoretical potential for carbon dioxide (CO2) storage in the country, data supporting initial estimations provided by the Atlas on the Geological Storage of Carbon Dioxide in South Africa study must be enhanced through the gathering of more data,” says South African Centre for CCS (SACCCS) manager Brendan Beck.
The SACCCS is mandated to investigate the feasibility of CCS in South Africa. Part of this work involves the geological exploration needed to establish if there is suitable geology in South Africa to safely and permanently store CO2.
Council for Geosciences Analytical Laboratory and Regional Geochemistry Business Units manager Dr Marthinus Cloete notes that more research and prospecting must be done to verify and characterise the basins to determine their suitability as CO2 storage sites.
There is insufficient data available to perform modelling of the sedimentary basins. Earlier studies used oil and gas survey data and all conclude that effective storage capacity assessment cannot be completed unless additional data is acquired, he says.
“Different data acquisition methods are being considered. To conduct modelling of the basins, a large quantity of data is needed to determine what is happening underground and enable more accurate prediction of the behaviour of any CO2 injected. Questions such as whether the CO2 will remain stationary and whether it will migrate over time are the focuses of research and must be determined as part of the overall assessment for the safe storage of CO2,” Cloete notes.
The Atlas on Geological Storage of Carbon Dioxide in South Africa, which was released in 2010, determined that 98% of potential storage is offshore. But the current research focus for a possible test injection is on the 2% onshore portions of the Outeniqua basin, called the Algoa basin, and the onshore portion of the Zululand basin.
The focus on onshore portions of the two basins reduces the costs involved in research and testing and better enable the development of local specialist skills capacity. Having the project onshore will also enable the public and government to witness the project and learn about the use of CCS technologies, says Beck.
“Building on the work of the Atlas, the SACCCS is now planning further exploration of these basins. Exploration will involve establishing the geological suitability of the regions and will be supported by environmental assessments and engagement with all relevant stakeholders. If this exploration is successful and an appropriate site is identified, the SACCCS will then look to develop a CO2 Test Injection Project to further evaluate and build experience around the technology in a South African context,” he says.
“The CO2 Test Injection Project will enable South Africa to better understand the role of CCS in reducing CO2 emissions and meeting the challenges of climate change. The test injection project is the next milestone in the South African CCS roadmap, which was endorsed by the Cabinet of South Africa in May.”
The endorsement of the South African CCS roadmap by Cabinet provides the framework for advancing the CCS work programme. The Department of Energy has also formed an interdepartmental CCS task team to develop legislation and regulations, based on inter- national best practices.
Meanwhile, the geological history of both coastal basins indicates they are geologically stable. However, while knowledge of the geology of the Outeniqua basin is bolstered by previous oil and gas surveys to map the oil- and gasfields in the basin, the presence of which also indicates that the basin has the right geological conditions required to sequester CO2, relatively little prospecting has been done in the Zululand basin, explains Cloete.
“The onshore Zululand basin consists mainly of a single basin, and is a potentially large saline aquifer that can, theoretically, be used for CO2 sequestration. The Algoa basin comprises several relatively small sub-basins and each of these has several potential saline aquifers,” he says.
Beck adds that around 6.5-million tons of CO2 are stored each year globally for the purposes of mitigating climate change. “The first large-scale project started storing CO2 in 1996 with over 65-million tons of CO2 stored across five large-scale projects (about one million tons a year) and a significant number of smaller projects,” says Beck.
“Building on these projects, 2014 will see the Gorgon CO2 storage project come on line in Australia, which will store 4.4-million tons a year. To put this in context, a 1 GW con- ventional power plant produces around three-million tons of CO2 a year.”
South Africa is engaging in several inter- national CCS forums, with significant expertise derived directly from international projects, he says.
There is significant international collab- oration and support for CCS. For example, the UK government announced a £60- million fund to demonstrate CCS in developing countries. In addition, there is much interest in sharing expertise in these forums between projects and governments with experience in CCS. “For example, the South African Centre for CCS is actively collaborating with projects such as the Otway CCS test project in Australia,” says Beck.
But there are also many critics. “Geological CCS technology is still in its infancy as far as the use on coal-fired power stations is concerned and it has not been done on a scale that is sufficient to convince us that the technology cost reductions look feasible. Significant ramp-up globally is needed,” warns WWF-South Africa Living Planet Unit head Saliem Fakir.
“The most optimal storage sites are offshore. This would make the storage of the gas at these sites prohibitive because the distance from coal-fired power stations to the storage sites can be 600 km to 1 000 km. There is also the issue of whether it is technically feasible to store CO2 deep beneath the sea,” Fakir adds.
“The presence of suitable sites offshore means that, economically speaking, we do not really have suitable sites for geological CCS. This implies further reducing our dependence on coal or looking at cheaper CCS options,” he says.
Therefore, the organisation does not believe the focus on CCS is making the best use of limited resources.
“South Africa does not have the depth of resources to develop innovations like these from conception to commercialisation. We should rather spend these funds on renew- able-energy technologies. We are better off spending on the scaling and development of concentrated solar power,” he adds.
South Africa should shift its research towards adopting clean technologies that are mature. Research should be focused on optimising these technologies for local conditions, says Fakir.
Further, CCS could result in a public liability issue. If the industry does not have some sort of State guarantee or risk insurance in case of public liability, the financing of CCS storage facilities and CCS itself becomes less bankable, he says.
“Our strength is in adoption, optimising and innovation through entrepreneurship. These are important comparative advan- tages that have worked with other technologies. Currently, some of the clean-energy technologies are costly and present technical barriers. We need to pick those we can spend as little resources on as possible but get the maximum of benefit,” avers Fakir.
However, the advocates believe South Africa, which produces more than 90% of its electricity from coal, has much to gain from pursuing the solution.
The main purpose of CCS is eventually to contribute to the mitigation of climate change through the secure storage of CO2, with important implications for South African food and trade security, concludes Cloete.