| || || Prasad, Ravita Devi|
| || || Assessment of wind resources and analysis of wind data for some locations in Fiji |
Author:Prasad, Ravita Devi
Institution: University of the South Pacific.
Call No.: Pac TJ 820 .P73 2008
Abstract: Due to the increasing power demand and the environmental concerns of the conventional power sources, power generation from wind is getting due attention from majority of power planners. The power output of a wind turbine is a cubic function of the wind speed. Doubling the wind speed can mean a substantial (8 times) increase in the energy output, thereby improving the economic viability of an installation. Wind resource itself is seldom a steady and consistent flow. It varies with the time of day, season, height above ground, and type of terrain. Proper siting in windy locations, away from large obstructions, enhances wind turbine's performance. A proper wind resource assessment (WRA) and analysis of the data collected is very important. This is because wind is an intermittent energy source and knowledge of economic viability of wind project is essential. It is vital to assess the wind power potential of a site with as much accuracy as possible, taking into account seasonal as well as yearly variations in the local wind climate. An extensive literature survey discusses about the different techniques of WRA. The methodology include discussions on preliminary wind survey to choose the optimum site for installing wind data instruments, choosing the optimum wind turbine for the site, ways to predict wind speed using Artificial Neutral Network (ANN) or measure correlate predict (MCP) method. The literature survey also discusses about the various software’s used in WRA and the statistical method of WRA. In statistical method, MCP method is described. During WRA when a site is chosen for wind monitoring, installation of wind monitoring equipment is done at that site. The wind data is then downloaded at regular intervals and regular site visits are made in order to ensure that proper management to the equipment and downloading of data is taking place. The Fiji Department of Energy (DOE) has done a lot in the renewable energy sector, especially in wind energy. Discussions on what the DOE has done till date and what are various ways to improve WRA are mentioned in this thesis. Wind data at Vadravadra village in Gau Island have been collected for three consecutive years at a height of 27 m on a 30 m tower installed on 137m iii Delainasinu hill by DOE. The wind characteristics for this site are determined using the available wind data and a detailed analysis has been carried out for this particular site in Fiji. The detailed analysis includes discussions on the wind characteristics at the site, the estimated energy yield, the determination of the optimum wind turbine for the site, economic analysis, and a hybrid energy system at the site. It has been established for Vadravadra that (i) the annual average wind speed is 6.18 m/s, (ii) for 68 % of the time in a year the wind speed exceeds 5 m/s, (iii) highest wind speed is recorded in June and July, (iv) optimum wind turbine is Fuhrlaender 30 kW wind turbine (FL-30), and (v) estimated annual energy yield from FL-30 wind turbine is 60000 kWh. To find the economic viability of the wind project an economic analysis is carried out. In the analysis, both situations, i.e., wind turbine alone and wind – diesel hybrid systems are analysed. The levelised cost of energy (LCOE), net present value (NPV), simple payback (SPB) period, internal rate of return (IRR) and benefit to cost ratio (BCR) are determined. Given that, wind alone may not be a feasible solution to provide electrical energy at remote sites a wind diesel hybrid configuration is also considered. In view of the fact that Vadravadra village currently receives electrical energy from a diesel generator (DG) set for 4 hours in the evening, a 24 hour load profile is made based on certain assumptions. HOMER software is used to find the optimum hybrid configuration in terms of cost. It has been found for Vadravadra that when a wind turbine alone is installed at the site then the cost of energy (COE) is F$1.32/kWh and when a wind diesel hybrid system is considered the COE is F$1.44/kWh. Finally, proper wind resource assessment for a particular site will lead to a successful wind energy system to be operated and managed at the site