The investigation of CO2 storage potential in the Algoa basin in South Africa

Abstract

Carbon capture and storage (CCS) is seen as one of the technical approaches that can be used to mitigate global climate change in fossil fuel dominated countries such as South Africa. Approximately 90% of primary energy in South Africa is derived from fossil fuels, with coal providing 92% of electricity production in the country. The South African Centre of Carbon Capture and Storage (SACCCS) was established in 2009 (by the South African government with the assistance from international governments and industry) to investigate the potential of CCS in the country. SACCCS is addressing its mandate in line with the South African CCS Roadmap, which has been endorsed by the South African government. SACCCS's role in the South African CCS Roadmap is as follows:2004Assessment of the potential for CCS in South Africa2010Development of a South African CO2 Geological Storage Atlas2017Commencement of a Pilot CO2 Storage Project (10,000 - 50,000t CO2 stored)2020Facilitate the commencement of a CCS demonstration plant (in the order of 100,000t CO2/year)2025+Inform the implementation of commercial CCS deployment (over 1,000,000t CO2/year)Ongoing:Provide support to other CCS activities in South Africa The results from the assessment of CCS potential in South Africa were summarised and documented in the Atlas (which was published in 2010) with the majority of storage potential occurring in Mesozoic basins of South Africa. There is 150 Gt of theoretical storage capacity is identified, of which 98% occurs offshore. After the completion of the Atlas the next stage on the Roadmap, the Pilot CO2 Storage Project (PCSP), has become the focus of SACCCS activities. The scope and available funding of the PCSP led to the decision to focus on the onshore portions of the Algoa and Zululand basins as possible sedimentary basins for the PCSP programme. This paper will discuss the progress associated with the ongoing investigation of CO2 storage potential in the Algoa basin which forms the onshore extension of the offshore Outeniqua basin. The middle Jurassic (Kimmeridgian) to lower Cretaceous (Hauterivian) Uitenhage Group constitutes the syn-rift basin-fill succession with stratigraphy dominated by the fluviatile Kirkwood Formation, and shallow marine Sundays River Formation. Due to limited and reasonably poor data availability, the need for new data and more tests on existing data to confirm any potential storage areas/sites was cited. SACCCS is now planning additional analysis of data to potentially allow for reinterpretation of the older data. The results from the analysis and reinterpretation will inform the next stage of the PCSP.