Geothermal energy is a renewable source that is almost unlimited in quantity. Derived from the amount of heat generated by the Earth’s core, it is a sustainable energy source that is currently not used in Australia widely. This is due to problems identifying suitable geothermal resources, producing it at a high rate and overcoming the upfront capital associated with the technologies and electricity conversion.

Geothermal energy may be stored in granite rocks or trapped in liquids (hydrothermal process). Many countries generate significant amounts of electricity from geothermal energy. Iceland sources 25 per cent of its total electricity generation from geothermal sources, with Phillippines and Kenya sourcing 17 per cent.

There are various types of geothermal energy with hot springs (volcanic activity) being the most common. other types include:

• hot sedimentary aquifers – exploit naturally occurring reservoirs that have been heated by proximate hot rocks or crustal heat flow
• enhanced geothermal systems – commonly referred to as hot rocks, these systems exploit the heat stored in rocks deep beneath the earth by fracturing the rock to create permeable reservoices
• direct use sytems – utilise shallow underground reservoirs where there is a slight temperature difference between the surface and groundwater.

Australia has no volcanic structures however there is significant potential for geothermal energy to be extracted using hydrothermal and hot fractured rock processes. with significant interest in sustainable energy in the face of climate change and zero-carbon targets, innovations to convert geothermal energy to useable electricity is expected to disrupt the energy and resources space

Commercial-scale geothermal technology in the Australian residential sector took a step forward in 2018 with Alinta energy announcing plans to commercialise geothermal heating and cooling.