Feasibility study of a hybrid energy system for sustainable energy production in Kiribati
Tarakia, Tiante T. (2009) Feasibility study of a hybrid energy system for sustainable energy production in Kiribati. Masters by Coursework thesis, Murdoch University.
This thesis presents a comprehensive energy resource assessment for Kiribati. The energy resources assessed are solar, wind and copra with CNO biofuel as a diesel substitute. The main aim is to assess the feasibility and economic viability of these energy resources as energy sources for a Hybrid Energy System (HES) that can provide a sustainable energy source for rural communities on outer islands in Kiribati. Arorae Island, is chosen as a case study to assess these resources, including the feasibility of local CNO production. In particular, the load is estimated and analysed for Arorae Island Council, for which a HES design is developed and assessed. The load pattern and design for this rural institution are assumed to be typical of the other island council institutions, though this thesis suggests that it is always vital to assess the load for particular users. Current CNO production on South Tarawa is also examined with consideration on its opportunity to replace diesel fuel. Interestingly, the findings reveal that it is economically viable to produce CNO on Arorae Island to meet the demand of CNO biofuel. This could possibly be the case for the other islands. The use of CNO as a diesel substitute is practical particularly in an indirect injection diesel engine for outer islands applications; these opportunities thus render CNO an attractive advantage as an alternative source of energy for the islands. A particular distinct aspect of this thesis is its findings in resolving certain technical issues related to CNO use in a diesel engine. The issue of deposits formation in particular is well discussed with the causes being resolved. The study also confirms the excellent solar resource of the island, as well as a potential wind resource of the island, especially for a HES use. In the HOMER design analysis, the viability of the HES using the RE sources are less attractive due to their very high initial costs and NPC. However, they are very cost-effective in terms of low operation costs and in substantial fuel savings. Some optimal systems can operate without a diesel genset which is highly economical on outer islands. Despite their high costs, there is still opportunities to reduce the load estimate and so the high capital costs of the RE systems. In addition, this thesis argues that HESs are viable provided there are external funding sources or subsidies available to meet the initial costs. Other important findings reveal that copra production for export is not viable, and CNO export is promising on a scale of economy given CNO favourable world price. The finding suggests that the country must invest now in CNO production both for export, as well as for biofuel use in order to fully realise the long-term economic benefits from the coconut resources. At current CNO production capacity by the KCMC, the country can replace at least 30 % of diesel fuel imports. This clearly implies that a large scale investment in CNO biofuel can displace considerable amount of diesel fuel. The current fuel shortages on the islands which correlate with inadequate fuel supply reserves, is bound to persist in the next decades or so given the economic vulnerability of the country to soaring world prices of petroleum fuels. Unless it is serious in seeking and developing its alternative sources of energy, over a long term, the country will continue to experience major economic setbacks, one of which is duly being the impact of world fuel prices. Overall, this thesis is novel and unique in many aspects of its assessment, and presents a comprehensive assessment on solar, wind and copra/CNO energy resources. One crucial part, is the feasibility of CNO production on outer islands and its use in a HES which is fully assessed for the first time.
|Publication Type:||Thesis (Masters by Coursework)|
|Murdoch Affiliation:||School of Engineering and Energy|
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