Geothermal energy is a renewable energy source that can be found in abundance on our planet. Only a small fraction of it is currently converted to electrical power, though in recent years installed geothermal capacity has increased considerably all over the world. This review focuses on Enhanced Geothermal Systems (EGS), which represent a path for turning the enormous resources provided by geothermal energy into electricity for human consumption efficiently and on a large scale. The paper presents a general overview of this ever-expanding technology from its origins to the current state of the art. The Geodynamics plant in Habanero (Australia), which started up on 2 May 2013, is the first privately-run commercial EGS plant to produce electricity on a large scale. Thanks to the technological development of EGS in recent years, the future looks bright for such plants in the decades to come.

Enhanced geothermal systems (EGS): A review

Thermal conductivity of soils and rocks from the Melbourne (Australia) region

To cope with tunnel frost damage, studies on prevention methods are routinely conducted to improve environmental protection and energy saving. Based on field investigations, the main available thermal insulation methods and their application are discussed and analysed in this paper. The results show that passive measures, such as a thermal insulation layer or door, cannot completely avoid frost damage. Construction investment of the electric heat tracing (EHT) system is lower at the early stage, but a large investment in operation and pollution problems are needed in the later period. As renewable, clean and environmentally friendly primary energy, geothermal energy can realize energy-saving and emission-reduction. Furthermore, our research team proposed the optimization design method for tunnel heat insulation and anti-freezing by using geothermal energy and presented the challenges for future applications of the ground-source heat pump (GSHP) system in tunnels. The results regarding energy conservation from this review can provide useful technical support in design, operation and management of tunnels in cold regions.

A state-of-the-art review of sustainable energy based freeze proof technology for cold-region tunnels in China

Economic analysis of vertical ground source heat pump systems in Melbourne

Evaluation of thermal efficiency in different types of horizontal ground heat exchangers

Geothermal energy, whether as a source of electricity or to heat or cool buildings, has an enormous potential as a renewable energy source. This paper presents a broad overview of geothermal energy, with a focus on the emerging technologies of Enhanced Geothermal Systems (EGS) and Ground Source Heat Pumps (GSHPs). EGS and GSHP systems are important because of their potential for widespread use, as opposed to traditional geothermal energy systems which are generally limited to tectonically active regions. Commercial application of EGS technology is some years off but its enormous potential demands investment for further research. GSHP heat pump technology is available now — policy makers need to be educated and the potential of GSHPs demonstrated. Research should focus on optimising the design of the in-ground component of GSHP systems to maximise their economic, as well as environmental, benefits.

Emerging geothermal energy technologies

Ground energy systems use the ground as a heat source or sink to heat and cool buildings. Because the ground temperature is more stable than the ambient air, ground energy systems can be more efficient than conventional heating and cooling systems. Ground energy systems typically comprise a ground heat exchanger (GHE) connected to a building’s heating and cooling system via a heat pump. The GHE is usually a closed loop of pipe embedded in the ground. Fluid circulates through the embedded pipes to exchange heat between the ground and the building. A research facility has been built at the University of Melbourne’s Parkville campus to experimentally study the effects of GHE configuration on ground energy system performance and investigate the potential to improve existing design techniques. This paper provides an introduction to ground energy systems and describes the experimental set-up.

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Papers

Emerging geothermal energy technologies

Experimental study of ground energy systems in melbourne, australia

Geothermal Energy: Introducing an Emerging Technology

Direct Geothermal Energy Demonstration Projects for Victoria, Australia

Geothermal energy in a sustainable built environment