Clean Energy Australasia (CEA) plans to generate base load electricity with Geothermal Energy and optionally augmented by peak load Solar Thermal Energy.
Geothermal Energy Sources
Geothermal energy in Australia can be sourced from two principal plays, namely Hot Rocks / Enhanced Geothermal Systems in granites and Hydro-thermal systems contained mainly in sediments and sedimentary aquifers shown diagrammatically in the pictures below.
Hot Rocks - Granites Characteristics Hydrothermal (Hot Sedimentary Aquifers)
- Fractured reservoir - Sandstone reservoir
- Heat generating & convective - Convective heat
- 1-4km depth - 1-km depth
- 100 – 200C - 75-150C
Further Technical Information on Enhanced Geothermal Systems (EGS)
Lawrence Livermore National Laboratories has carried out extensive studies on EGS and presented the concepts in a video presentation on University of California television here entitled "Harnessing the heat beneath your feet". This video is a 45 minute presentation that deals with the technology in some depth explaining the science in easily understood terms and demonstrations. So sit back, relax and become informed about EGS without the hype.
Hot Rocks Geothermal Energy
Graphic courtesy of ANU
- Water pumped into injection well
- Circulated through fractured hot rocks several kilometres below the surface
- Super-heated water / steam is then returned to the surface through production well
- Super-heated water / steam is used to generate electricity
Organic Rankine Cycle
The prime surface technology for converting geothermal heat to transmittable electrical energy is the Organic Rankine Cycle (ORC). An ORC plant has the capability of extracting useful work energy from low temperature hot water in the range of 75 to 200 degrees C. To achieve this a secondary (binary) fluid that has a lower boiling point is used to drive the turbine generator.For an ORC plant technical presentation please view here.
Solar Thermal Energy
Solar Thermal Plant, Southern Spain
Graphic Courtesy Solucar PS10
- Mirrors used to focus solar energy
- Receiver generates super-heated steam
- Steam to generate electricity
- Electrical energy storage option to provide additional electricity
- Potential to enhance geothermal peak-load generation during daylight hours