Charged with power – SA one of nation's big players in the renewable energy future

Adelaide Advertiser
16 July 2011, Page: 75

THE energy sector in Australia is under increased scrutiny, building towards its biggest overhaul in decades under the proposed carbon tax that kicks in on July 1 next year. The sector is the biggest contributor to greenhouse gases in Australia due to the way in which most of the energy is generated. While consumers are being educated to save and get smarter about using less energy, efforts are under way to unlock the huge potential of the country's natural renewable energy resources. The national renewable energy target is set at 20% by 2020.

South Australia's energy mix is better than most states and its share of total nationwide greenhouse gas emissions was just 5% in 2009. It also has a more ambitious 33% renewable energy target by 2020. But there is a long way to go in terms of investment, firstly in research and development and, subsequently, in generation and transmission infrastructure before renewable energy can be a reliable supply source. SA's power portfolio can be explained in two ways by total installed capacity of power plants and by actual contribution to demand in a given year.

Temperature, the age of the plant, outages and wear have an impact. At higher temperatures or during peak demand, the efficiency of some generators decreases. For wind farms, output may be limited to prevent overheating of the turbines. By way of installed capacity, SA has two coal fired power stations at Port Augusta, seven natural gas, three distillate and two dual fuel plants with an installed capacity of 3687 MW.

Some of these are used as base load power plants that produce electricity at the lowest cost of any type of plant and are most economically used at maximum capacity. Others simply lie idle for much of the year, used only during peak demand. Consequently, in terms of actual contribution to energy demand, more than 70% of the power comes from some coal-fired plants (44%) and the Playford and Northern coal fired plants (30%).

The Australian Energy Market Operator estimates the two coal fired and two gas plants took on most of the energy demand in the 2010-11 financial year. Closure of either of the coalfired plants by the indicated date of 2014 could lead to a power crisis given the expected increase in demand from the mining sector, the desalination plant and electrification of the train network. On the renewables front, there are 14 operating wind farms with an installed capacity of 1150 MW and 72 MW of solar power.

"With enough investment, South Australia could be a major national player in clean power generation, maximising on our competitive advantages", Renewables SA commissioner Tim O'Loughlin said. Wind energy contributed to just over 20% of the energy demand last financial year, but this can vary based on wind speed, availability, temperature and transmission network limitations. The wind farms operated at less than 40% of their capacity in 2010-11.

The growth in wind generation and variability makes management of the transmission network and power system challenging. The State Government says the Green Grid project a $4.5 billion investment plan, of which $2 billion is proposed for SA, to harness wind power on the Eyre Peninsula and export it interstate will be key to resolving this challenge. The state has a high quality resource for large scale solar installations, but the capital costs are high. Currently, roof top installations are the only significant contributors to the power grid.

With a rush of households signing up before federal subsidies ended, the installed solar capacity is expected to reach 100 MW in the near future. Geothermal energy derived from the natural heat of hot rocks deep underground is still in the experimental phase but has huge base load potential. Research is ongoing, especially in the state's north, with almost 30 companies and more than 400 exploration licences.