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Media Release

June 3, 2005

Calculating the future of wind farms

A model developed by researchers at the University of South Australia to calculate variability in the electricity generated from wind farms could be a key tool for future planning of renewable energy sources in the state.

What is important in electricity generating systems is not just how much power can be generated but how variable or reliable that supply might be, according to Dr John Boland from UniSA’s Centre for Industrial and Applicable Mathematics and the Environmental Modelling Research Group.

“Any electricity generating system that relies on natural forces, like wind or solar energy from the sun, experiences variability. If energy suppliers can predict drops in voltage or expected power shortages at peak times, the stability of the supply can be maintained using backup measures,” Dr Boland said.

UniSA researchers developed the mathematical model for the Electricity Supply Industry Planning Council (ESIPC). It includes data on the output variability at different time scales based on the statistical characteristics of Starfish Hill Wind Farm, combined with wind measurements from the Bureau of Meteorology. The ESIPC sees the model as an important tool to calculate what the output variability might be for a diversified system of wind farms, including wind farms under construction or planned for the future, based on wind characteristics in different parts of the state.

The first wind farm in South Australia, Starfish Hill was selected for its consistently strong winds, sparse settlement, low impact on native flora and fauna, and accessibility to a main road and utilities. Sweeping across two hills on the Fleurieu Peninsula near Cape Jervis, the wind farm is considered to be one of the best locations in Australia for wind-generated power.

With a total of 23 wind turbines, each with a capacity of 1.5 megawatts, Starfish Hill Wind Farm, run by Tarong Energy, generates enough power to meet the energy needs of about 18,000 households, which is sufficient to meet the annual needs of Kangaroo Island and the local Fleurieu Peninsula.

“Because of the way in which the national electricity market works, being able to predict the output variability at different time scales is particularly important in electric power considerations, even over very short intervals. Electricity is dispatched in five minute intervals so it is important to know how much variability there is in the generating system over that time frame. Knowing the output variability in half hour time frames and longer is particularly important to meet peak electricity demands because power suppliers need sufficient forewarning to start and reach the operating level necessary to meet customer demand.

“Because of the particular energy needs in Australia, with more peak demands than many other nations, modelling the output variability of wind farms is probably more crucial here and therefore further advanced than anywhere else in the world.

“The probability of exceeding the level of variability within different time scales can be determined using our model and then be addressed to ensure the smooth operation of the wind farm’s electricity generation system,” Dr Boland said.

Because of the competitiveness and success of Starfish Hill Wind Farm in providing additional and renewable electricity to the state’s power grid, many more companies are keen to establish wind farms and be rewarded with renewable energy credits.

Dr Boland believes that industries should be building more wind farms on a range of sites across the state rather than concentrating them in one or two areas.

“Greater diversification would have many advantages for South Australia. If the wind drops at one site, access to energy from other wind farms with greater wind speeds would reduce the level of output variability and increase the stability across the whole wind farm generation system.

“I would also like to see diversification into other forms of renewable energy such as solar to guarantee consistency. If we have different types of energy input that complement each other, the state can rely on a regular and stable supply of clean, cheap renewable electricity generation. But the biggest reason for this movement towards renewable energy is to cut greenhouse gas emissions and reduce our ecological footprint,” Dr Boland said.

It is estimated that Starfish Hill will reduce Australia’s greenhouse gas emissions by the equivalent of up to 2.1 million tonnes of carbon dioxide during its forecast 25 year operating life. Other wind farms now in service or under construction in South Australia will multiply those savings ten times.

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