Melbourne Energy Institute

Geothermal

Overview

Geothermal energy is the heat escaping naturally from the earth’s interior and it is reflected by a global surface heat flow of more than 40 TW. As such, interpreted onshore crustal temperatures in Australia can be translated into an extraordinary energy output of approximately1.9E25 Joules. For comparison, if only 1% of this energy in place could be harnessed before being lost to space, it would represent approximately 25,000 times our present annual electricity consumption nationally.

The climate change issue, energy security concerns and ‘near-peak oil’ have promoted renewed interest in geothermal energy as a mainstream energy option. Geothermal power is arguably one of the only sustainable technologies capable of contributing significantly to our future needs for large scale, low emission, base-load power at a competitive cost.

The Melbourne Energy Institute fosters multi-disciplinary research capabilities in realising our State and Nation’s geothermal energy potential, with a particular focus on improved targeting of geothermal resources, and geothermal reservoir characterisation through predictive modelling.

Research Themes

Conventional Geothermal

Geothermal energy is first thought of as heat energy discharged by hot springs and geysers, and often these are associated with the tectonics of plate boundaries. For instance Iceland, Japan and New Zealand are all using successfully conventional geothermal power to produce electricity because of their proximity to plate boundary activity. In Australia, despite the absence of plate boundary activity and volcanism in the recent past, our continent remains relatively hot on account of the radiogenic heat produced by elevated concentrations of naturally occurring potassium, thorium and uranium isotopes. In the appropriate geological context, what is commonly referred to as ‘hot rocks’, or ‘hot dry rocks’ is a geothermal reservoir that has the potential to be ‘stimulated’ by way of hydraulically induced microfractures in order to mimic the hydrothermal systems of conventional geothermal sources. A stimulated geothermal reservoir is an engineered (or enhanced) geothermal system (EGS).

Enhanced Geothermal

Engineered (or enhanced) geothermal system (EGS) comprises a geothermal reservoir that has been subject to hydraulic stimulation inducing enhancement of microfractures, porosity and permeability, although, depending on the geological context, a geothermal system that utilizes a sedimentary aquifer will be referred to as Deeply Buried Sedimentary Aquifer (DBSA).

The Geothermal Research Energy Group at the School of Earth Sciences focuses its research on the optimization of geothermal reservoir targeting. Conventional geological studies and geophysical analyses, combined with thermal and predictive numerical modelling permit to minimize the financial exploration risks associated with geothermal resource characterisation. Research teams at the School of Engineering are investigating improved drilling technologies; reservoir design, thermodynamics, stimulation and management; as well as environment impacts and risk assessment.

Projects

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