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Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau
Thesis (MEng)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613735663697920 |
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| access_status_str | Open Access |
| author | Richardson, Elizabeth Helen |
| author2 | Theron, Andre K. |
| author_browse | Richardson, Elizabeth Helen Theron, Andre K. |
| author_facet | Theron, Andre K. Richardson, Elizabeth Helen |
| author_sort | Richardson, Elizabeth Helen |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131899 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:40:52.447Z |
| 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:10019.1/131899 Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau Richardson, Elizabeth Helen Theron, Andre K. Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Tidal power -- Guinea-Bissau Renewable energy sources -- Guinea-Bissau Islands -- Power supply -- Guinea-Bissau UCTD Thesis (MEng)--Stellenbosch University, 2024. ENGLISH ABSTRACT: A review of tidal energy converting systems, focused on tidal stream systems, as well as the environment of the study area, is used to inform a multi-criteria assessment (MCA) of potential device alternatives. Due to the relatively new nature of such technologies, limited information is available. Cross flow turbines are favoured both because of favourable Capex indicators, low cut-in current speeds, favourable efficiencies, ability to be applied at the required scale and sufficient literature and a successful similar deployed example at the required scale, optimising the certainty of the scoring. The MCA results should be confirmed through a facilitated MCA workshop including multiple stakeholders on implementation of the study. Following the MCA, a 2D numerical model is developed in the MIKE 21 Flow Model FM (Flexible Mesh) suite. A calibration of modelled water levels revealed model accuracy within approximately 12% water level predictions obtained from C-MAP, a well renowned developer of nautical charts. The tidal current speeds are also validated against Navionics indications of current speeds and favourable agreement is found. No data measurements for a conventional calibration are available in this remote area. The model is set up at a regional scale and allowed the identification of tidal current hotspots. The most suitable of the hotspots, based on suitably shallow bathymetry and location not within a nature reserve, are identified as Sites 1 to 5. These sites are then further characterised in terms of bathymetry, presence of vessel traffic and associated risks, distance offshore and to potential demand centres. Site 1 has among the most favourable hydrodynamics along with Site 4, both showing a modelled mean current speed of 0.67 m/s. However, Site 1 is excluded due to deep bathymetry and potential risk of entanglement with illegal fishing vessel nets or anchors. Sites 2 is excluded due to unfavourable hydrodynamics and deep bathymetry, with mean current speeds of 0.52 m/s. Site 3 has the slowest current speeds, with mean current speeds of 0.45 m/s, but Site 3 is the only site close to a significant demand centre, the town of Bubaque. Site 5 has mean current speeds of 0.61 m/s, slightly less favourable than Site 4. The decision between Sites 4 and 5 and feasibility of tidal energy at either of these sites depends on which transmission scenario will be more feasible, longer subsea cable for Site 4; compared to longer landside cable routing, as well as crossing of the 0.8 km channel between Ilha de Rubane and Ilha de Bubaque, for Site 5. More detailed modelling based on bathymetry measurements at Site 3, or identification of an additional site within proximity of Bubaque and with more favourable hydrodynamics than Site 3, is recommended. AFRIKAANSE OPSOMMING: Die meeste Suid-Afrikaanse strande het onvoldoende monitering, wat 'n holistiese begrip van kuslyn-dinamika te midde van toenemende omgewings- en menslike drukke belemmer. Hierdie studie het hierdie kritieke kennisgaping aangespreek deur 'n satelliet-afgeleide kuslyn algoritme, CoastSat, te gebruik om jare se onvoldoende monitering aan te spreek en by te dra tot 'n deeglike begrip van Suid-Afrikaanse kuslyn-dinamika. Verbeterings is aangebring aan die oopbron CoastSat algoritme om 'n semi-outomatiese, nasionale toepassing moontlik te maak. Gevolglik is 'n baanbreker databasis geskep wat strek vanaf 1984 tot 2023 en byna alle sandareas van die Suid-Afrikaanse kuslyn dek. Hierdie uitgebreide en samehangende databasis verteenwoordig die eerste van sy soort vir Suid-Afrika. Die akkuraatheid van die satelliet-afgeleide kuslyn data (SDS) is beoordeel deur dit te vergelyk met Lidar topografiese data van 27km strandgebied oor ses verskillende strande in die eThekwini Munisipaliteit. Die resultate het 'n baie sterk korrelasie (R = 0.95) tussen die SDS en die gemete Lidar data getoon, alhoewel 'n algehele landwaartse verskuiwing (“bias”) van 11.2m waargeneem is. Deur golfoploop in die ontleding in te sluit, is die akkuraatheid aansienlik verbeter, wat die verskuiwing met tot 79% verminder het. Hierdie bevindings is in ooreenstemming met vorige studies van regoor die we reld wat ook CoastSat gebruik het. Benewens die ontwikkeling van hierdie uitgebreide kuslyn-dinamika databasis, is vier plaaslike gevallestudies en vier streeksassesserings uitgevoer. Hierdie studies het twee prime re doelwitte gedien: om die begrip van Suid-Afrikaanse kusdinamika beide plaaslik en op streeks basis, te bevorder en om die nut van die databasis te demonstreer. Byvoorbeeld, (i) 'n Studie van die Tugela Riviermond het kuslynerosie van verskeie honderde meter van 2005 tot 2023 getoon, wat belangrike inligting is vir deurlopende en beplande opvangsgebiedprojekte, soos groot damme, wat die toevoer van riviersand na die kus beï nvloed. (ii) Die volgehoue groot kusopbou suid van die Richardsbaai hawe-ingang het skerp gekontrasteer met die erge erosie na die noorde. Dit het die impakte van verskeie kusingenieurs-intervensies uitgelig, wat waardevolle insigte in hul doeltreffendheid verskaf en kusbestuurstrategiee advies bied. (iii) Studies van die seisoenale kuslyn-veranderinge by St Helena Baai en Kaapstad se baaie (Vals- en Tafelbaai) het getoon hoe die omvang van hierdie veranderinge verband hou met golf blootstelling. (iv) Streeksondersoeke het interessante verskille in kuslynevolusie gevind: byvoorbeeld, die weskus het tipies kuslyn-erosie gedurende die winter ervaar, die suidkus het minder ekstreme winter erosie ondervind, en op die ooskus, veral vanaf Port St Johns noordwaarts, het die grootste erosie verskuif vanaf winter na lente. Hierdie bevindings is van groot waarde vir plaaslike, streeks en provinsiale kwesbaarheids-studies asook meer effektiewe toewysing van hulpbronne. Masters 2025-04-08T07:51:13Z 2025-04-08T07:51:13Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131899 Stellenbosch University xi, 111 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Tidal power -- Guinea-Bissau Renewable energy sources -- Guinea-Bissau Islands -- Power supply -- Guinea-Bissau UCTD Richardson, Elizabeth Helen Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title | Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title_full | Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title_fullStr | Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title_full_unstemmed | Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title_short | Tidal energy feasibility for small island communities in the Bijagos Archipelago, Guinea-Bissau |
| title_sort | tidal energy feasibility for small island communities in the bijagos archipelago guinea bissau |
| topic | Tidal power -- Guinea-Bissau Renewable energy sources -- Guinea-Bissau Islands -- Power supply -- Guinea-Bissau UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131899 |
| work_keys_str_mv | AT richardsonelizabethhelen tidalenergyfeasibilityforsmallislandcommunitiesinthebijagosarchipelagoguineabissau |