Located “between latitudes 15° and 24° S, the tropical island nation of Fiji has been a keen advocate of the United Nation‟s climate change initiatives, and in particular the Paris” Agreement.
Abstract
Located “between latitudes 15° and 24° S, the tropical island nation of Fiji has been a keen advocate of the United Nation‟s climate change initiatives, and in particular the Paris” Agreement. To meet the goals highlighted in the articles of this Agreement, Fiji has produced its own Nationally Determined Contributions Implementation Roadmap (NDC-IR) with plans to reduce the business as usual (BAU) CO2 emissions from its energy sector by 30% by the year 2030 in comparison to 2013 (the reference year). A notable feature of the NDC-IR, however, is the non-inclusion of wind energy in its Renewable Energy options.
The “current study presents a comprehensive feasibility study of the wind energy alternative, comprising wind resource assessment, potential power and energy output analysis, comparison of energy and exergy efficiencies, economic evaluation and emissions analysis to evaluate the percentage share of NDC targets that can be” met. The wind resource assessment of the study was undertaken for the four sites at Yaqara, Rakiraki, Rarawai and Navua using 10-minute interval data over two years (for Yaqara, Rakiraki and Navua) and eight years (for Rarawai) period obtained from Fiji Meteorological Services.
Considering the mean wind speed, in comparison to the other three sites, Rakiraki is the most viable option for commissioning a wind farm, with a higher mean wind speed of 6.190 m/s in the prevailing South-East direction. However, this information is not enough for determining the best site. Thus, the capacity factor values of two different turbine models (Vestas V27 225 kW and Vergnet GEV 275 kW) were computed by deriving the best probability distribution function (PDF) equation. The PDF with the best fit to the observed data out of the three tested PDFs of Weibull,Gamma and Lognormal was found to be the Weibull distribution function.
Key results attained revealed that the Vestas model for Rakiraki had the highest capacity factor of 0.31. As for the average annual output power and energy, the single Vergnet model for Rakiraki produced the highest values of 0.0721 MW and
600.139 MWh, respectively. In general, the Net Present Value (NPV) of the project involving Rakiraki site using Vestas turbine was the highest under all scenarios, with Levelized Cost of Energy (LCOE) and Pay-Back Period (PBP) being the lowest. It was observed that the two policy indicators; the proposed feed-in tariff (FIT) rate of FJD$0.39 and production tax credit (PTC) of FJD$0.015 increased the NPVs, indicating a higher net profit. Furthermore, it is clear that Rakiraki (with average AEP estimate of 22,205.14 MWh for the 37 Vergnet turbines and 21,678.70 MWh for the 37 Vestas turbines) is the more viable site for commissioning a wind farm over the other three sites. Moreover, the Vergnet model for the Rakiraki site resulted in the most GHG saved (in tCO2-eq) when replaced with the thermal sources (i.e., industrial diesel oil and heavy fuel oil). Hence, the GHG Pay-Back Period for Rakiraki using Vestas model was the lowest. More importantly, it was found that the Rakiraki site could meet up to 37% of the short-term target (from 2017 – 2020) set for the first sub-sector of Fiji‟s NDC-IR. Therefore, the sites can be ranked from best to worst as: Rakiraki, Yaqara, Navua and Rarawai. Apart from its main objective of assisting with Fiji‟s NDC-IR process, this research also provides pertinent information to the government, decision and policy makers, developers, and potential investors in making well-planned decisions in regards to wind energy, thus enabling the usage of a bigger mix of renewable energy resources to meet the ambitious targets much faster.