Medupi Flue Gas Desulphurisation: Technology Selection Study Report

The report recommends the installation of Wet FGD (WFGD) technology without a flue gas cooler for the Medupi Power Station in South Africa. While Dry FGD (CFB) uses less water, it is rejected due to 53% higher operating costs, 9% higher capital costs, and the requirement for high-quality lime sourced from the Northern Cape. WFGD is preferred for its higher efficiency on high-sulphur coals, its ability to use local lower-quality limestone to stimulate regional economic development in Lephalale, and its alignment with the Phase 2A water augmentation project.

• Medupi Power Station must implement FGD technology to meet South African statutory SO2 emission limits of 500 mg/Nm3 for new coal-fired power stations, as typical operating levels without FGD are approximately 4000mg/Nm3, requiring a nominal removal efficiency of about 87.5%.
• The study identifies Wet FGD (WFGD) and Dry FGD - Circulating Fluidized Bed (CFB) as the leading commercially available technologies capable of meeting the required emission standards at Medupi.
• Wet FGD is characterized by high removal efficiency (greater than 98%) and high reagent utilization (95 to 97%) for high sulphur fuels, and it produces gypsum that can be sold for wallboard or concrete manufacturing.
• Dry FGD-CFB is best suited for low to medium sulphur coals and produces no wastewater stream, but its by-product (a mixture of ash and scrubber by-product) has no known commercial use and must be landfilled.
• The implementation of Dry FGD (DFGD) would result in a 9% higher capital cost than Wet FGD due to required ductwork modifications and the addition of a new fabric filter system. Additionally, DFGD operating expenses are estimated to be 53% higher than WFGD, primarily due to the higher cost of the lime reagent.
• WFGD is recommended over DFGD because it can utilize lower-quality limestones sourced closer to the power station, supporting socio-economic development in Lephalale, Marble Hall, and Thabazimbi, whereas DFGD requires high-quality hydrated lime that would need to be transported from the Northern Cape.
• While adding a flue gas cooler to a WFGD system could reduce water consumption by 20-30%, the option is deemed unfeasible for Medupi due to practical challenges regarding maintainability, plant availability, and negative feedback from three European power stations visited during benchmarking.
• The water supply for the recommended WFGD system is linked to the Phase 2A water augmentation project, which aims to utilize surplus return flows from the Crocodile catchment for industrial use in Lephalale.
• The total annual water requirement for CFB-FGD is approximately 60% of that required for WFGD, but when considering the full value chain (including sorbent processing), the total water requirement for CFB-FGD is 3,910,298 m3/annum compared to 6,547,852 m3/annum for WFGD.
• The incremental difference in the electricity tariff increase between the Wet FGD and CFB-FGD technologies is estimated to be approximately 0.45%.

APA

Centre for Environmental Rights (n.d.). Medupi Flue Gas Desulphurisation: Technology Selection Study Report. https://cer.org.za/wp-content/uploads/2022/06/Annexure-B-Medupi-FGD-Technology-Study-Report-Rev-2-0-FINAL.pdf?x21779

Chicago

Centre for Environmental Rights. Medupi Flue Gas Desulphurisation: Technology Selection Study Report. n.d. https://cer.org.za/wp-content/uploads/2022/06/Annexure-B-Medupi-FGD-Technology-Study-Report-Rev-2-0-FINAL.pdf?x21779.

Wikipedia

{{cite report |author=Centre for Environmental Rights |title=Medupi Flue Gas Desulphurisation: Technology Selection Study Report |url=https://cer.org.za/wp-content/uploads/2022/06/Annexure-B-Medupi-FGD-Technology-Study-Report-Rev-2-0-FINAL.pdf?x21779 |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{centreforenvironmentalrightsndmedupi, author = {{Centre for Environmental Rights}}, title = {{Medupi Flue Gas Desulphurisation: Technology Selection Study Report}}, institution = {Centre for Environmental Rights}, url = {https://cer.org.za/wp-content/uploads/2022/06/Annexure-B-Medupi-FGD-Technology-Study-Report-Rev-2-0-FINAL.pdf?x21779}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }