To follow up on an earlier posting I did on this topic, it appears that Petratherm one of several companies trying to develop electricity source from hot subterranean rocks has has some good results recently, and is moving on to the first stages of drilling to produce a pilot power plant.
Geothermal is one of the few alternative energy sources that can actually produce base load electricity. Even if you don’t believe (or are unconcerned by) the perils of global warming this is a good thing. It promises to be a vast and cheap source of electricity.
Australia’s emerging geothermal energy sector has been boosted with confirmation from new tests that a South Australian exploration well has officially recorded one of the country’s highest “hot rocks” temperatures at levels much closer to surface than previous such wells.
The Paralana-1 geothermal test well result paves the way for ASX-listed Petratherm Limited to now consider the feasibility of moving to the third stage of its project to develop a commercial geothermal resource in far north South Australia.
This stage would drill two new wells nearby to Paralana-1 but up to twice the depth of the test well, to prove up the expected thermal resource, undertake circulation tests and establish an underground heat exchanger. Under this trial heat exchange program, water would be pumped from surface down one of the new wells and circulated through hot rocks at approximately 3.6 kilometres depth. It would then be returned to surface via the second well as superheated water able to produce steam to drive electricity generators. The drilling and circulation work would be a precursor to developing an electricity generation plant at Paralana of around 7.5 Megawatts capacity to supply local demand.
In results released today from formal temperature tests on the latest drilling of its Paralana-1 well,130 kilometres east of SA’s main electricity grid infrastructure at Leigh Creek – Petratherm said the well achieved the Company’s expectations of target temperatures of 200oC at a depth of 3.6 kilometres. The tests were carried out last week after the well returned to its normal thermal or temperature equilibrium within its rock strata after being drilled a further 1300 metres deeper late in June to its second and final stage depth of 1,807 metres.
The recorded temperature in the bottom of the hole – at equilibrium – is 109oC.