Hot Rocks - Journey to the Centre of the Earth

With hydrogen not quite the 'poster child' of alternative energy it was just few years ago and others concerned about the amount of land required to grow crop for biodiesel, it's time for a new knight in shiny armour to enter stage left (to mix a few metaphors!) So let's get deep. Real deep. It seems that while our oil reserves were the result of decaying plant and animal matter, there is another continuing decaying process occurring. In this instance, isotopes of potassium, thorium and uranium. Such decay contributes to a situation whereby 99% of planet is hotter than 1,000oC. The map shows the regions in Australia where, close to the crust, can be found rocks of about 350oC (in red). In short the idea is to drill a hole about 4-5km deep, Pour water down it, have these 'hot rocks' heat the water and return it to the surface so the energy can be extracted via a heat exchanger in a power plant. The water then heads off down again for another trip, through a closed loop system. If the resource can be tapped it could provide Australia with its current level of energy consumption for the next 7,500 years! The idea was first proposed by the US's Los Alamos National Laboratory in '72. Technically it is called "Hot Dry Rock (HDR) geothermal energy" and is recognised by the International Energy Agency as 'renewable energy'. Read heaps more at ::Australian National University