- Tony Wright
- The Age, January 10, 2009
WHEN explorer Major Thomas Mitchell meandered across western Victoria in 1836, so enraptured by the vast grasslands that he called the place Australia Felix, meaning lucky or blessed land, he could not have imagined that even greater fortune lay thousands of metres below his feet.
Now, as the world grapples with the perplexity of how to produce energy without pouring greater amounts of pollutants into the atmosphere, new explorers are about to try to tap that invisible power, as green as the pastures above.
It is in the form of vast aquifers of ancient brackish water heated up to 145 degrees lying beneath a blanket of sedimentary rock at depths between 2.4 kilometres and more than four kilometres. And as these new explorers have found, it is not limited to western Victoria. Two companies — Greenearth Energy and Hot Rock — are in a race to exploit this previously ignored resource, which is superheated by sitting atop deep beds of granite warmed by the Earth's mantle.
It is a race, however, given little impetus by the Rudd Government's recent decision to reduce carbon emissions by 5 per cent to 15 per cent by 2020. The policy continues to favour coal-fired power stations, which means the old polluting technology retains a significant price advantage — about half the megawatt price — over geothermal technology, which requires large amounts of start-up money, particularly for drilling.
Between them, Hot Rock and Greenearth have been granted by the Victorian Government geothermal exploration permits covering more than 46,000 square kilometres stretching from the Latrobe Valley in Gippsland, across Geelong and along the entire stretch of the west Victorian coast and its hinterland.
Deep beneath those great tracts of land, the companies have ascertained, lies the potential to make Victoria one of the world's greenest baseload energy suppliers — a goal neither wind nor solar power can achieve.
Greenearth's 18,795-square kilometre tenements are in the Latrobe Valley and the Bellarine Peninsula, Geelong and Daylesford areas. Early last month, it published Victoria's first "inferred geothermal resource", showing that beneath a large area between Geelong and Anglesea lies enough stored heat energy to provide 150 times Victoria's energy requirements. This week it published another such report on discoveries beneath Gippsland, including the Latrobe Valley. The potential, according to Greenearth managing director Mark Miller, is for these areas to produce many hundreds of megawatts of "clean, safe, renewable energy at the doorstep of our two great Victorian cities, Melbourne and Geelong".
Hot Rock's 27,000-square kilometre exploration area extends from Lorne for 270 kilometres to the South Australian border. Major centres covered by the company's permits include Colac, Terang, Warrnambool, Hamilton and Portland.
While Victoria as a whole has long overlooked its ability to fire up its industries and cities using the free heat sizzling deep in the earth, the potential was hardly unknown. For more than 20 years, Portland was the only city in Australia that used geothermal power to heat many of its larger public buildings and its public swimming pool. Its ageing bore, sunk a relatively shallow 1400 metres beneath the city, produced water at 58 degrees but was dismantled two years ago. Gas is now used as an alternative heating source while the city fathers ponder whether to reopen the geothermal plant.
Hot Rock, basing its venture on an independent review and the discovery of great pools of hot water during previous drilling for oil and gas across western Victoria, believes there is enough geothermal power available within its tenements to generate up to 5000 megawatts, or almost Victoria's entire electricity requirement.
Essentially, the process involves drilling to the aquifers and pumping the water to a plant at the surface where the heat is extracted to drive turbines. The water is then returned to its aquifer through re-injection wells. There are no toxic emissions and there is no loss of water.
And unlike major geothermal schemes unfolding in South Australia's remote Cooper Basin, the Western District and Gippsland permits lie along major power transmission systems. In monetary terms, this is crucial — new electricity transmission lines cost between $1 million and $2 million a kilometre. In short, the power — in baseload form, which produces electricity 24 hours a day like power from coal- fired plants — could be transmitted at minimal cost across a relatively small area populated by 5 million people.
"I have never been involved in an environmental project that ticks every conceivable box, but this one does everything — that is, except serious government support," says Hot Rock's managing director, Dr Mark Elliott.
Greenearth and Hot Rock plan to start work on their initial projects in the middle of this year. Hot Rock plans to begin proving its strategy by drilling and testing two wells north-west of the town of Koroit, near Warrnambool, and building a 50-megawatt power plant in about two years.
Eventually, assuming significant investor support, several other power plants producing about 200 megawatts — more than all the wind farms now operating in Victoria — are to be built at the Koroit site.
In the long term, Greenearth's Mark Miller sees his company moving beyond electricity production to helping the Latrobe Valley's coal-fired plants clean up their act. He believes that heat extracted from its Gippsland tenements could dry the wet sludge known as brown coal, reducing toxic emissions from existing power plants.
Even the doughty Major Mitchell may have been impressed.
Tony Wright is national affairs editor.