This article summarises the proceedings of the carbon capture and utilization workshop which was organized by the South African National Energy Development Institute (SANEDI) and took place in Sandton on 18 February 2020.
Coal remains the backbone of South Africa’s economy through the supply of energy, and contributes 70% of primary energy input, consisting of 90% of electrical power generation and 30% of liquid fuels. Coal is expected to continue to form a significant component of South Africa’s energy generation mix for many years to come. The future focus for coal power generation will be on highly efficient, low emissions (HELE) plant. Low emissions can be achieved through carbon capture, utilisation or storage (CCU/S).
The original aim of CCS was carbon capture and storage, where the CO2 would be stored in geologically suitable sinks. Problems with finding suitable structures, and objections from environmental organisations have led to other options for handling the captured CO2 to be investigated. Potential issues associated with sequestration in geologic formations include: permanence, long-term monitoring, and verification, with many unknown effects and potential risks still to be determined.
CCS is part of long term mitigation scenarios, as well as a flagship programme of the white paper on climate change strategies. Cabinet endorsed the CCS road map in 2012 and it is part of the NDP. Ongoing projects include:
- Feasibility of a pilot CO2 capture plant using renewable energy in South Africa
- Carbon capture and storage road map for South Africa
- Carbon dioxide mineralisation roadmap for South Africa
CCS roadmap comprises the following five phases:
- Assessment of CCS potential in South Africa (completed in 2004)
- Atlas on geological carbon dioxide storage for South Africa(completed in 2010)
- Pilot CO2 storage project planned for 2017 (consultation started)
- CCS demonstration planned for 2020
- Commercial CCS application by 2025
The original focus for CCS in South Africa was on geological storage. Without safe and permanent storage CCS would not be viable. South Africa is a leading developing country in CCS and has made good strides in research into its potential use through the SA Centre for Carbon Capture and Storage (SACCCS), a collaborative research organisation launched in 2009, which operates as a programme within the South African National Energy Development Institute (SANEDI).
South Africa, which releases 450 MT of CO2 into the atmosphere every year, can be justifiably proud of the progress it has made on its CCS roadmap for close to 15 years. The roadmap started in 2004, with extensive assessment of the potential for CCS in South Africa; in 2010, it incorporated the development of an atlas of geological storage of CO2; and the current phase is the SACCCS Pilot Carbon Dioxide Storage Project (PCSP) with the aim to inject 10 to 50 000 tons of CO2 into a pilot well. CCS is expected to reduce emissions by 327 MT CO2 to 2050, and 15,6 MT per annum between 2030 and 2050.
Public perception is one of the reasons that many CCS projects have failed globally. Communities will not be willing to accept perceived impacts of CO2 generated elsewhere.Communities will want to benefit in some way from projects. Access rights and land use has been highlighted as one of the major problems for onshore projects.
Carbon capture and usage/mineralisation
There are numerous potential uses for CO2 in the petrochemical, fuel, pharmaceutical and fertilizer industries (organic chemical). Current industrial demand for CO2 likely to be much less than the production, so re-use of CO2 will not provide large scale absorption of the product. Future developments may change this. Some suggest that this shows greater potential than CCS, but cost is still a concern and the market for products can impact viability. The subject still requires research and development in different sectors.
Mineralisation of carbon dioxide (CO2), or mineral carbonation, is receiving much attention worldwide at the moment. The process involves the reaction of CO2 with materials containing alkaline earth oxides like magnesium oxide and calcium oxide (CaO). For large-scale CO2 capture and sequestration (CCS) purposes, this makes use of the vast resources of magnesium silicate minerals that are available worldwide, resulting in an environmentally benign magnesium carbonate product that needs no post-storage monitoring. Most attention is focused on the production of valuable calcium carbonates from industrial by-products and wastes and this has the potential to develop into a profitable technology. Mineralisation is being investigated as part of the CCUS project.
Status of South Africa’s project
The project study has identified several suitable onshore and offshore sites in the coastal area of South Africa (Fig. 1). A potential site for the pilot, that offers ideal geological structures for CCS, has been chosen in northern KwaZulu-Natal. The priority now is intensive stakeholder engagement. Locals (who do not have access to grid electricity) are understandably unimpressed by having this product resulting from electricity generation dumped in their territory.
Fig. 1: Possible sites for CCS (SANEDI).
CO2 sequestration will require the gas to be at the supercritical state. In this state the CO2 is in a fluid state. Deep wells below 800 m are required to maintain this state, which requires a pressure of at least 70 kPa. Offshore sites provide natural hydrostatic pressure at depths below 800 m. Injection requires an oil extraction-size well which costs approximately R6-million to drill.
Cost is a very important barrier to CCUS globally at present, especially in developing countries due to competing demands for resources and attention. The cost of production will be increased by CCS, as will the usage of water and energy.
Legislation and regulation
There is no legislation covering CCU/S at the moment, and the implementation of CCS requires legislative process and support from the government. Policy certainty related to carbon tax, budgets and tax incentives is also required. There are different acts across the country that can be amended,coordinated, streamlined and used to create a legislative framework for the development and deployment of CCS.
A consortium established in 2012 identified the following possibilities as frameworks for legislation:
- National environmental waste management act
- National environmental management act (NEMA)
- NEMA and Mineral and petroleum resource development act (MPRDA)
- A free-standing CCS act
There are currently no South African standards covering CCS, but standards are under development by the International Standards Organisation (ISO), as well as by the American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC) which could be adopted and adapted for local use.
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