Geothermal Energy Centre of Excellence
School of Mechanical & Mining Engineering

Achievements

The Queensland Geothermal Energy Centre of Excellence (QGECE) was established in 2009 with a grant of $15 million from the Queensland State Government to help accelerate the development of the Queensland and Australian geothermal energy industry through a managed program of strategically targeted research, development and demonstration projects in innovative technologies in close collaboration with the Queensland State Government and other key stakeholders. The global network of collaborators with the QGECE now includes geothermal companies, equipment manufacturers, renewable energy consultants, universities and national and international energy agencies.

The QGECE since its beginning in 2009 has engaged in extensive and on-going discussions with the Australian Geothermal Energy Industry and Commonwealth and State Governments to assess what needs to be done to realise Australia’s geothermal energy potential. The main challenge is the difficulty in bringing hot water to the surface in sufficient quantities to justify the large investment in the geothermal wells. The corollary is the imperative to extract the maximum possible power from that expensive brine before it is injected back into the underground reservoir. As well, all potential future geothermal power generation sites would be located inland in arid country and unless efficient air-cooled condenser technologies can be developed, they would fail to realise up to 20 per cent of their power generation capacity.

With the determination to be ready with solutions for these problems when the geothermal companies start producing power, the QGECE embarked on an ambitious research program to develop new and better methods of transforming the heat resource in geothermal brine to electricity and to do so with minimum use of fresh water. The QGECE adopted a strategy of addressing the fundamental issues concerning power conversion and air cooled condensers rather than running after quick partial solutions. As a result of our investment over the years in developing the requisite skills and research laboratories, the QGECE is now the only team in Australia with the international reputation and the recognised capability to develop efficient and cost-effective geothermal power technologies.

This strategy has paid off in two ways. Firstly, the QGECE is now in a position to assist an Australian geothermal power developer to produce up to 50 per cent higher power compared what can be supplied by off-the-shelf products. Secondly, the QGECE solutions are applicable not only to geothermal power but to all power generation from renewable heat. This second assertion is supported by over $7.5 million funding QGECE has received in the concentrating solar thermal power generation area that assures the sustainability of the Centre until 2020.

While concentrating on power generation, the Centre did not ignore the fact that, at least for the geothermal investment sites in 2009, the generated power had to be transmitted over large distances. A project investigating the feasibility of bringing that power to the coast was completed earlier this year and a technical report was released at the time of the 2013 Queensland Geothermal Workshop.

A fundamental program examining the nature of the Queensland heat source and searching for areas of geothermal potential closer to potential customers in inland Australia was also undertaken by the QGECE. Prior to this research, it was generally believed that high-heat producing granites were the principal source of geothermal heat in Australia and all exploration was directed according to this paradigm. This research has identified local hot spots in certain areas of Queensland where the crust was thin and the contribution of the mantle heat was as significant as the heat from the hot rocks. Some of these hot spots are in areas where local communities are served by relatively expensive diesel generated electricity providing potentially quicker paths to commercialisation for the geothermal sector.

Capabilities

  • Assist geothermal companies with the analysis of surface alterations and surface and borewater geochemistry to develop a better understanding of geothermal prospects
  • Identify and assess the suitability of conventional and EGS (Enhanced Geothermal Systems) reservoirs for electrical power generation
  • Identify and assess the suitability of conventional and EGS (Enhanced Geothermal Systems) reservoirs for electrical power generation using a CO2-based geothermal system
  • Find the most efficient power plant design for converting low-temperature (<200 oC) heat to electricity; to assist with the selection of an off-the-shelf solution to realise this design; to design and manufacture customised equipment when an off-the-shelf solution is not available.
  • Design of water sprays and/or wet media installations for precooling the cooling tower inlet air to maintain thermal power plant performance on very hot days
  • To suit small- to medium-scale renewable power plants (<10MW),  produce fabrication-ready designs for low-cost natural draft dry- and hybrid-cooling towers
  • Dynamic analysis of geothermal and solar thermal power plants to enable deployment of these plants in a dispatchable mode or in parallel with a fossil-fuel burner back-up
  • Design and analysis of concentrating solar thermal power plants
  • Design and analysis of geothermal power plants

Australia offers the perfect learning curve for CST but only with suitable technology

The experience curve is a simple concept: the more we build of the same technology, the more affordable it gets. This happens because, as we build new systems, we also develop all new ways of producing them simpler, faster, and cheaper. In our view, the number of commercial installations is more important than the cumulative installed capacity while developing an experience curve. There are lessons for the Concentrating Solar Thermal (CST) technology in this assertion. Although CST started in 1980s, it has failed to develop an experience curve the way photovoltaics did. This is because all past CST technology has been based on steam power cycle, which cannot be built feasibly at small sizes. If were were able to build a compact steam machine, our cars would be running on steam power. The significance of this point is now beginning to berealised by the CST sector. An experience curve for CST can only be achieved if commercial CST power generators can be offered at relatively small sizes, i.e. at sizes 5-10 MWe. The sCO2 systems have the potential to make this possible and will help the CST sector quickly develop a sizeable experience curve. Australia offers the perfect opportunity to make this happen. The map below the Australian off-grid and fringe-off-grid installations using diesel power. Replacement of diesel with small CST systems is commercially feasible but only a CST technology can be offered that can be downscaled. The cost reductions to be realized through the remote area experience can then be translated to utility-scale systems without requiring substantial public subsidies.

Research Facilities

The key testing and development infrastructure includes the following:

  • Pinjarra Hills Renewable Power Generation Laboratory
    The laboratory includes a high temperature/high pressure test loop for designing and testing advanced turbines.
  • UQ Gatton Air-Cooled Condenser Test Facility
    This was originally built for testing airborne pesticide spray applications. It was refurbished to investigate advanced air-cooled heat exchangers, with and without water sprays, for hybrid cooling applications.
  • Portable Test Plant
    QGECE and its research partner Verdicorp built this portable test plant to demonstrate new QGECE technologies in the field. A facility unique in Australia, this is a demountable power plant designed for geothermal applications. It can be configured for other alternative power generation applications.
  • Geochemical Isotope Analysis
    This analysis is combined with surface outcrops and shallow water geochemistry to identify and characterise deeper geothermal resources
  • Power Network Analysis
    This analysis is designed to identify cost-effective options for bringing remote renewable power generation to the Queensland power grid