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A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater
van Zyl, S. D. 2025. A Sensitivity Analysis on the production of Potable Water, Green Hydrogen and Derivatives from South-West African Seawater. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/6ed82ebd-be0f-4b40-832a-acb904c5a763
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613915089731584 |
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| access_status_str | Open Access |
| author | Van Zyl, Shane David |
| author2 | Burger, A. J. |
| author_browse | Burger, A. J. Van Zyl, Shane David |
| author_facet | Burger, A. J. Van Zyl, Shane David |
| author_sort | Van Zyl, Shane David |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | van Zyl, S. D. 2025. A Sensitivity Analysis on the production of Potable Water, Green Hydrogen and Derivatives from South-West African Seawater. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/6ed82ebd-be0f-4b40-832a-acb904c5a763 |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132328 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:43.080Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132328 A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater Van Zyl, Shane David Burger, A. J. Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Clean energy Derivatives (Chemicals) Saline water conversion Capital investments Hydrogen -- Analysis UCTD van Zyl, S. D. 2025. A Sensitivity Analysis on the production of Potable Water, Green Hydrogen and Derivatives from South-West African Seawater. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/6ed82ebd-be0f-4b40-832a-acb904c5a763 Thesis (MEng)--Stellenbosch University, 2025. ENGLISH ABSTRACT: The global shift towards green energy has placed significant focus on the potential production of green hydrogen and its derivatives. Demineralised water is required for effective production of hydrogen via electrolysis and desalination/demineralisation facilities therefore form an inherent part of the production train of such hydrogen. For the operation of electrolyser facilities at the West Coast of Southern Africa, water would generally be sourced from the sea, requiring full-blown sea water desalination systems. Since the West Coast region is mostly arid, with economic activities often limited by a lack of fresh water, it may be beneficial to produce additional potable water in conjunction with the production of demineralised water for down-stream hydrogen and/or ammonia generation. This study examined various production scenarios. Specifically, it considered the impact of prominent variables on capital expenditure (CAPEX), operational expenditure (OPEX), levelised cost and the environmental impact. A sensitivity analysis was employed to provide critical insight as to the process parameters with the largest effect on the levelised costs of various products. Furthermore, a sensitivity analysis on the direct environmental impact was done to gauge the effect on greenhouse gas emissions and brine discharge. The effect on the CAPEX costs of the process plant when providing additional water treatment capacity to produce potable water for nearby towns/communities was explored. Additionally, CAPEX and OPEX distributions were provided to indicate individual process unit contributions to the overall costs. The findings of the study confirmed that the most influential process parameter on the levelised cost of all green hydrogen products and green ammonia was the electricity requirement per kg of hydrogen. A decrease in 10% of the electrical requirement to produce 1 kg of hydrogen resulted in ca 10% saving in terms of levelised cost of low-pressure hydrogen, 9.1% on compressed hydrogen and 6.8% for liquid hydrogen and 4.8% for green ammonia. Furthermore, decreasing the battery energy storage system (BESS) capacity and increasing the wind capacity factors played a crucial role in reducing the overall levelised costs of products due to a decrease in the levelised cost of electricity that this provided (roughly 40% reduction). A sensitivity analysis on the effects on the environmental impacts revealed that the greenhouse gas emissions were, again, most affected by the electrical requirement for hydrogen production. A decrease in 10% of the electrical requirement to produce 1 kg of hydrogen allowed for a 10% decrease in the emissions of the plant. Furthermore, the recovery of the seawater reverse osmosis plant had the greatest influence on the cost, quantity and quality of brine discharge. A 10% increase in the water recovery caused a 16.5% cost and quantity reduction in brine discharge, however worsening the brine quality by 8%. Furthermore, increasing the potable (only) water production capacity, to a fraction of 90% of the total water production, minimally affect the overall CAPEX. The CAPEX fraction associated with the additional water treatment capacity increased to ca 2.6% of the total CAPEX. The results emphasize that additional potable water production can be provided at minimal additional CAPEX for green hydrogen and green ammonia production, allowing a large potential social benefit through increased potable water production to decrease water scarcity in the south-west African region. The individual process unit contribution to the overall CAPEX and OPEX were determined to allow an understanding of the total process costs. The renewable energy generation and BESS storage is the major contributor to the production plant CAPEX (69% to 88%) if a large-scale BESS is included in the system. However, when minimising the BESS size and increasing the wind capacity factor, it was found that the onshore wind contributed significantly to the CAPEX and OPEX of the overall plant. The green hydrogen production component (electrolyser and balance of plant, excluding compression and liquefaction) contributes largely towards the total OPEX costs, between 59% and 83% of the total if the cost of electricity is included. Excluding the cost of electricity resulted in the renewable energy generation components and BESS (if included) contributing significantly to the OPEX costs. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-06-04T05:59:01Z 2025-06-04T05:59:01Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132328 en Stellenbosch University xxi, 245 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Clean energy Derivatives (Chemicals) Saline water conversion Capital investments Hydrogen -- Analysis UCTD Van Zyl, Shane David A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title | A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title_full | A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title_fullStr | A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title_full_unstemmed | A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title_short | A sensitivity analysis on the production of potable water, green hydrogen and derivatives from South-West African seawater |
| title_sort | sensitivity analysis on the production of potable water green hydrogen and derivatives from south west african seawater |
| topic | Clean energy Derivatives (Chemicals) Saline water conversion Capital investments Hydrogen -- Analysis UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132328 |
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