Alinta Ltd is a large player in Western Australia’s electricity market. In May 2002, Alinta Ltd signed a Memorandum of Understanding (MOU) with Alcoa World Alumina Australia (AWAA) to build a series of cogeneration units that could produce up to 1,200 MW of generation capacity.
The first two cogeneration units are located at the AWAA’s Pinjarra Refinery. All electrical power generated by the cogeneration unit will be supplied to Alinta customers through Western Power Corporation’s South West Interconnected System (SWIS). The waste heat will be used to produce high-pressure steam, which AWAA will use initially to generate electrical power at the existing Pinjarra Powerhouse, and then used to provide heat in the alumina refining process.
The Pinjarra cogeneration units each comprise a 140MW gas turbine generator and a Heat Recovery Steam Generator (HRSG) with the capability for supplemental duct firing to increase steam production. Steam production without duct firing is 210 tonnes per hour and this can be increased up to 430 tonnes per hour with the duct burners fully fired.
The first cogeneration unit, which has proved to be extremely reliable, was put into commercial operation in March 2006 and the second in February 2007.
Hatch was engaged by Alinta Cogeneration Pinjarra Pty Ltd to undertake Project Management, Procurement Management and Construction Management.
The GTG and HRSG were designed, supplied, erected and commissioned under an EPC contract. Other packages for interconnection services between the cogeneration unit, the refinery and the SWIS were separate contract packages tendered, awarded and managed by Hatch.
At the end of February 2007, total site hours worked were 1,206,518. This had been achieved without a lost time injuries being recorded.
