The engine, produced in partnership with Granite Power, is particularly focused on electricity generation from geothermal sources and industrial waste heat streams, such as waste heat from petrochemical plants, cement and brick manufacturers, gas and coal-fired power plants.

GRANEX is an innovative development stemming from conventional organic rankine cycle (ORC) technology, which is transformational for low to medium-heat resource opportunities such as recovered waste heat (RWH) and the geothermal sector. At present, ORC is the principal means of converting electrical energy heat sources into the range of 130–250°Celsius.

By incorporating the concept of the regenerative supercritical rankine cycle, GRANEX significantly improves the efficiency of the conventional rankine cycle, increasing the net electrical output from a 200°Celsius heat source by approximately 40 per cent. The technology has only a moderate impact on plant capital costs, no hazardous fluid is involved in the process, and no CO2 or other waste emissions are generated.

GRANEX has been developed jointly by Newcastle Innovation (University of Newcastle) and GRANEX Technology, with the assistance of a Renewable Energy Development Initiative (REDI) Grant from AusIndustry, and an ARC Linkage grant. Worldwide patent protection has been applied for, and GRANEX Technology has the exclusive worldwide commercialisation rights to GRANEX.

Following completion of the research and demonstration plant program, GRANEX Technology has commenced marketing and sales of GRANEX to the recovered waste heat, geothermal, and solar thermal sectors worldwide.

GRANEX represents an advance in the worldwide development of geothermal resources, such as engineered geothermal systems (EGS), including hot rocks and hot sedimentary aquifers, and provides significant risk mitigation in developing these resources. For EGS, the increase in net electrical output is approximately 50 per cent, taking into account overall greenhouse gases and other pollutants.

According to the inventors, the indicative cost of EGS electricity using currently-available technology is approximately $90–100 per megawatt per hour (MWh), the equivalent of greenfield black coal power plant costs as coal prices approach export parity, and is of less cost than wind or solar-generated power. GRANEX could even reduce the cost of geothermal EGS electricity to $70–80 per MWh.

This technology is also particularly suitable for waste heat recovery applications in the temperature range of 100–450°Celsius, generating useful electricity from the heat in flue gas from gensets, coal-fired power stations, cement kilns, and other industrial processes.

The technology recently received the honour of being named a nominee in the 2010 EcoGen Most Outstanding Technology Awards.

GRANEX 1 kW Test Plant

The 1 kilowatt (kW) proof-of-concept power plant has extensive instrumentation and data logging facilities, and is designed for testing a wide range of working fluids over a temperature range of 80–450°Celsius.

This facility is now being used for ongoing research and development as well as undertaking testing programs on potential commercial applications. This can be in either GRANEX or ORC modes of operation, with condensing or non-condensing heat sources. This test work enables the selection of working fluid and process parameters to be optimised for the application in question.

GRANEX 100 kW Prototype Plant

The 100 kW Prototype Plant, located at the University of Newcastle’s Callaghan Campus, is specifically designed to demonstrate GRANEX technology in geothermal and waste heat applications in the 150–250°Celsius temperature range.

The Prototype Plant was officially opened in 2009 by Jodi McKay, New South Wales Minister for Hunter and Science and Peter Primrose, New South Wales Minster for Mineral Resources.