Practical Completion of 1 MW Power Plant and Visitor Centre
Following the Habanero 3 well control incident the construction crew for the 1 MW plant was demobilised until the well was brought under control and the control measures which were identified by the risk assessment of the Habanero 1 well were implemented. The construction crew was then remobilised in the last week of June to finish the work that remained outstanding at the time of the incident. The construction activities were completed and cold commissioning activities commenced in early July. Cold commissioning was successfully completed and the construction crew demobilised in mid July. The 1 MW Power Plant was officially handed over to the Power Engineering and Operations Group as of 31 July 2009. Hot commissioning is yet to be completed on the 1 MW Power Plant and the timeframe for this is yet to be determined and is dependent on re-establishing a fuel source following the Habanero 3 incident. The Joint Venture will determine the future location and commissioning timeline for the 1 MW plant as the work program unfolds and well locations are determined.
 Construction of Power Line from 1 MW Plant to Innamincka
At the time of the Habanero 3 incident all construction work on the overhead power line to Innamincka had been completed. Work to be completed in order to energise the line consisted of a small amount of Electrical Code of Compliance (ECC) work (ensuring property wiring in the township was up to code) and connecting the properties to the consumer mains. Commissioning of the power line remains under a suspension notice and any activities related to the power line will not be carried out until the commencement of the 1 MW hot commissioning.
Challenges in delivering the 1 MW Power Plant
The 1 MW power plant is unique, in that there is no other power generation plant that uses water at the high pressure encountered at Habanero. The geofluid production pressure of 350 bar is greater than the main steam pressure of a coal fired supercritical power station. Although this may sound like a positive feature it has caused significant difficulties with the reinjection pump. The reinjection pump is used to add another 100 bar of pressure to the geofluid in order to pump it back underground. The conditions have proved challenging for all pump and seal suppliers and although they were willing to rate their seals for our conditions, the margins are slim resulting in the pump being unreliable. The suction end of the reinjection pump needs to be sealed to prevent the geofluid leaking back out along the motor shaft and there is no known seal manufacturer who has successfully managed a fluid at this pressure. A global search for an alternative pump has identified two possible solutions; one a down hole pump which does not require a seal and the other an above ground centrifugal pump with a triple seal. Further investigations are being carried out to evaluate their suitability for both the 1 MW power plant and future larger plants.
The brine chemistry is also unique with the unexpected deposition of stibnite from the brine to the brine cooler tubing (which would also occur in heat exchangers). Methods to eliminate or manage this problem are currently being investigated. The results of the investigation into the Habanero 3 well failure has prompted a review of materials used in the surface works of the 1 MW plant in addition to those materials under consideration for the Commercial Demonstration Plant (CDP). Geodynamics will construct a test rig, to be incorporated into the 1 MW plant, to validate the findings of the investigations into both the stibnite deposition and the material selection.
Although the 1 MW plant hot commissioning was not completed (due to the Habanero 3 incident) the cold commissioning was completed. This provided valuable information regarding the control system of the plant and improvements have already been considered for the CDP.
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