| dc.description.abstract | Electricity supply is a strong precondition to economic growth and development at all levels. However, the kind of electricity service and the mechanisms involved are of paramount importance in ensuring sustainability. Renewable energy systems integration to grid is considered one of the promising alternatives however, effective policy mechanisms as well as technical infrastructure shaping are necessary elements for such realization. Due to the power of these components, renewable energy technologies have been vigorously promoted in developed countries, hence addressing their energy concerns and improving the living standards of their populace. By contrast, this is not the case in the African context, and more specifically the case study country. In view of the above background information, this research work is therefore aimed at gridintegration of renewable energy power plants in the African context, looking at the case of Nigeria. This was done by first looking at a general energy landscape and renewable energy market in the global context as a kickstart and driver to the policy task direction of the dissertation. On the technical bit, physical component modelling, optimization, energy management and evaluations, detailed sensitivity analysis, energy efficiency assessment, economic benefits evaluation of systems switching, extrapolation assessment at bigger capacity, and environmental life cycle assessment were conducted by a combination of software packages viz.: Hybrid Optimization Model for Electric Renewables (HOMER), Microsoft Excel, Ganzleitlichen Bilanz (GaBi), and some databases. On the complementary
policy bit, in-depth analysis based on defined indicators was conducted of the existing renewable power policy in the global context for a continental cluster of highly performing countries, with narrowing to the case study country existing power policies. The lessons obtained from both the technical and policy aspects with added innovative thoughts were sufficiently applied in the formulation of the appropriate policy instruments for the case study country while also evaluating the risks associated. As a supplementary and final deliverable, grid-infrastructural assessment was conducted in evaluating the appropriate grid-based
mechanisms in favour of integrating the renewable energy system to the utility grid of the case study country.
Regarding the obtained results, it is evident on the technical part that the transition from the standalone system to the proposed grid-connected hybrid system led to drastic reduction in the optimized sizing and ultimately 3% increment in overall energy supply, 68% and 85% decrement in net present cost (NPC) and levelized cost of energy (LCOE) respectively, with avoided emissions at the operational level. The energy efficiency incorporation to the proposed grid connected system resulted in more commendable transition based on the further decrease in optimized sizing and ultimately 88% and 81% reduction in overall NPC and LCOE
respectively. Regarding the supplementary economic benefits of the system switching from the standalone to the proposed grid-connected system, the observed savings translated to a payback period (PBP), discounted payback period (DPBP) and internal rate of return (IRR) of 6.09 years, 7.18 years, and 16% respectively. Same economic benefit analysis on the adoption of the energy efficiency to the proposed grid-connected system resulted in observed PBP, DPBP, and IRR of 1.78 years, 1.99 years, and 56% respectively. The extrapolation assessment to the proposed grid connected system and its energy efficiency measure over 50 decentralized systems showed clearly the economy of scale benefits. With respect to the environmental impact of the proposed grid-connected system execution on life cycle ground, the analysed impact categories mainly the global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), human toxicity potential (HTP), and the abiotic depletion potential (ADP) after an uncertainty assessment incorporation revealed 21.3 - 33.38 g CO2 – eq./kWhelec., 1.077 – 1.663 g SO2 – eq./kWhelec., 0.134 - 0.197 g phosphate eq./kWhelec., 6.33E-11 – 1.01E-10 g R11 – eq./kWhelec., 29.65 – 46.09 g DCB – eq./kWhelec., and 0.246 – 0.383 MJ/kWhelec.. respectively. Different possible scenarios
considered from the proposed grid-connected system in this regard combined with the gridonly power of conventional system generation path showed clearly the different impacts on the life cycle environmental performance indicators for proper decision.
Further quantitative results of the grid-integration of the hybrid renewable power systems that focussed on the grid-infrastructural concerns has been the utility grid extension measures. The quantified extension distance on average (Dav.) in ensuring the viability of the whole extrapolated power system grid-integration was 0.5 – 1.6 km, which ultimately gave a total distance (DTotal) of 25 – 80 km. In line with this foundational case, the capacity of distance (CoD1) in respect of the total extrapolated capacity of the proposed grid-connected system was found to be 32,000 – 102,400 MW.km, whereas, for the extrapolated capacity on energy
efficiency incorporation gave a capacity of distance (CoD2) of 18,025 – 57,680 MW.km. In view of these grid-extension quantifications, the equivalent investment costs (I.Cs) were determined for both the CoD1 and CoD2 in ranges viz. 43.6 – 526.5 Million Euros and 24.6 – 296.6 Million Euros respectively.
Further quantitative results of the grid-integration of the hybrid renewable power systems that focussed on the grid-infrastructural concerns has been the utility grid extension measures. The quantified extension distance on average (Dav.) in ensuring the viability of the whole extrapolated power system grid-integration was 0.5 – 1.6 km, which ultimately gave a total distance (DTotal) of 25 – 80 km. In line with this foundational case, the capacity of distance (CoD1) in respect of the total extrapolated capacity of the proposed grid-connected system was found to be 32,000 – 102,400 MW.km, whereas, for the extrapolated capacity on energy
efficiency incorporation gave a capacity of distance (CoD2) of 18,025 – 57,680 MW.km. In view of these grid-extension quantifications, the equivalent investment costs (I.Cs) were determined for both the CoD1 and CoD2 in ranges viz. 43.6 – 526.5 Million Euros and 24.6 – 296.6 Million Euros respectively. | en_US |
