As mechanical engineers work across a large number of industries, SAIMechE stays abreast of developments which will affect our members, readers and the country as a whole. Here Dr Karen Surridge, Renewables Manager at the SA National Energy Development Institute (Sanedi), covers the release of its first technical assessment toward a Clean Coal Roadmap.
A new report on clean coal technologies has presented a case for potential opportunities and challenges associated with adopting these in a roadmap towards 2030. The report constitutes phase I in a roadmap towards providing an overview of the current energy carbon landscape in South Africa, the fossil fuel value chains and a high-level qualitative approach to ranking various technologies.
Transition
A number of countries, including South Africa, are set to have coal in their systems after 2050 owing to the lifespans of the newer coal-fired power stations. The report assesses the feasibility of South Africa introducing technologies to stay carbon neutral when residual anthropogenic carbon remains in the system post 2050.
The world is in transition on many levels and energy is part thereof. The focus on climate change is driving key energy decisions internationally and, as always, there are trade-offs to be made in our choice of energy. This, therefore, creates an opportunity to reflect on the future that we envisage and find the road to get there.
“To facilitate these choices, this study was initiated to provide valuable insight, mainly into the available technologies for the more effective and efficient generation of power and addressing the Green House Gas (GHG) emissions produced from these activities,” says Karen.
Three options
This phase of the work by Sanedi provides three high level technology roadmaps, i.e. for Power Generation, Liquid Fuels Manufacturing and Transport. “These roadmaps do not dictate technology choice but provide options indicating which technologies are relatively more efficient and their contribution towards GHG emissions reduction.”
The report assesses possible pathways to introduce clean coal technology as well as options for carbon abatement, carbon capture utilisation and storage (CCUS) and others, at existing or new coal fired power stations.
It is clear from the study that CCUS is most definitely an avenue that, if explored, would make a significant contribution to CO2 emissions reduction. At present, there are limited coal power plants with CCS, due to the high costs involved. Currently, 37 CCS projects are in operation, under construction or in advanced development around the world with a total capacity of 78 million tons CO2 pa (including all fossil fuel plants, not just coal). Major CCS hubs are located in the USA, China, Scandinavia, the UK, Saudi Arabia and the UAE.
To introduce such technology, South Africa will need to invest in the pipeline and other infrastructure to process, store and transport carbon dioxide to use it in bi-products thereby creating a closed system in which CO2 is captured, stored and reused.
Other technologies
Various other additional low carbon technologies are explored for the South African context including renewable energies such as wind, solar and biogas. The pros and cons of each technology are thoroughly examined in the context of South Africa’s opportunities and limitations in potentially scaling the various options. The technologies applied to electricity generation as well as transport and green hydrogen (green H2) technology.
The report emphasises that the current transmission and distribution infrastructure capacity is a constraint for alternative energy scaling and needs to be upgraded to support the new generation capacities. It is estimated that it could take up to eight years to upgrade and the Environmental Impact Assessment (EIA) process is the critical path for these projects. However, a number of projects piloting low carbon technologies are currently getting underway.
Geological formations
The Council for Geoscience (CGS) is piloting a Carbon Capture and Storage (CCS) project by conducting research that aims to identify geological storage formations that would be appropriate for storing carbon dioxide. This work is funded by the South African government and the World Bank. The pilot project aims to store 10 000 tons of CO2. The site is located in Leandra region in Mpumalanga close to the Sasol Secunda plants and consists of a basalt geological structure which needs to be investigated as a suitable CO2 storage environment.
Sasol plans to produce Safe Aviation Fuels (SAF) at their Secunda petrochemical plant using the FT process and green H2. Production of petrol and diesel can be replaced by SAF. They also have the option to replace carbon fuel production with sustainable chemical production. The plan is to supply the OR Tambo airport with SAF and thereafter supply the export market.
Less competitive
The Council for Scientific and Industrial Research (CSIR) has done extensive modelling around various scenarios of electricity supply and demand and for a variety of energy mixes based on IRP2019. In all scenarios, coal power with CCS is more costly than other alternatives such as renewable power.
Coal plants with High Efficiency Low Emissions (HELE) technology such as ultra-supercritical plants do perform at higher energy efficiencies (40% plus), however, the additional capital and operational costs of carbon capture and storage make them less competitive than renewable power.
Renewables
The cost of solar PV and wind has decreased significantly over the past 10 years with average tariffs decreasing some 80-90%. This trend is expected to continue as capacity at scale is developed.
The CSIR has found that there is a role for natural gas in peaking load service (Open Cycle Gas Turbines – OCGTs) to cover the variability of renewable power. They don’t recommend building baseload gas power (Combined Cycle Gas Turbines – CCGTs) because it risks lock-in of gas technology. However, the footprint required by renewable power installations is relatively large.
Large expanses
Studies have shown that SA is richly endowed with large expanses of land where solar and wind resources are abundant. Availability of land is not considered a constraint, though compliance with regulations to utilise this land must be followed.
The development of technologies and industries that will reduce GHG emissions is a key focus area worldwide. Additional policies and regulations support the development environment and commercialisation of new technologies and to develop industries. This can be achieved through a variety of means, including tax incentives, carbon taxes, grants, subsidies, investing incentives and equity funding.
Interesting to read that something may start to happen without the emotive rhetoric clouding the issue.
Dust and pollution control has long been integral to industrial plants but because it is a direct cost, it was ignored when there was profit to be made.
Combustibles will always be present, there exist numerous methodologies to clean up the chemical reaction – use them.
I remember the local tar works recovering useful solvents from coal and coke oven products extracted for use in blast furnaces.
When easy oil runs dry, perhaps some of the ‘old tech’ will need to be re-invented.
I wish you success in your beneficial research.