A wind energy resource survey of New Zealand

An error in production has resulted in there being no page 128, however there is no text missing.The work described in this thesis forms part of the New Zealand Wind Energy Resource Survey. It is in two parts. The first part provides an overview of wind energy in New Zealand in terms of supply and demand. Supply is related to the meteorology and geography of the country. The general problems of extrapolation and interpolation of wind data both in space and time are discussed and current knowledge on the subject is reviewed. The indications using available wind data are that there is an abundance of wind turbine sites with mean wind speeds high enough to drive conventional large-scale turbines economically. The limitation on wind power usage would be the ability of the electricity grid to accept the fluctuating supply rather than the magnitude of the supply. A complete assessment of the economics of wind power requires simulation of the grid operation. However there are several points favourable to wind power which are elucidated. New Zealand has a hydro-based electricity system and this is particularly suitable for the incorporation of wind power. The geographical extent of the country permits the output from wind power to be steadied considerably by dispersing the turbine network widely. The supply of wind at times of high demand and high hydro storage water value is generally average to high. However on an inter-annual scale, dry years may be accompanied by lighter winds. The second part describes the development and testing of OAWM, a computer model of wind flow over complex terrain. A survey of possible approaches shows the objective analysis technique to be the most suitable for wind energy applications. The model is tested on a set of field data collected from the Port Hills region, near Christchurch. Preliminary analysis of the data brings to light the complexity of the wind flow in the lowest 1000 metres as well as illustrating the usefulness of principal components analysis when applied to vector wind data. Tests of OAWM show that the most important phase in the objective analysis of wind data is the initial estimate of the windfield by interpolation of given data. The difficulty of this in regions of complex flow presents the greatest limitation in the use of OAWM. However several applications of the model to wind energy surveying are suggested