The expansion involves constructing a 120-megawatt nominal peaking power generator next door to the existing 95MW facility.
Natural gas will be supplied to the plant via the SEA Gas Pipeline that connects Adelaide with the southeast Australian network.
The expansion is due to be completed in the December quarter of 2008, in time to provide additional peak electricity capacity for the summer of 2008-09.
Managing director Grant King said the additional peaking capacity would help secure electricity supplies in the state, while helping Origin to balance its risk exposure.
“The power station will take advantage of open cycle gas turbine technology to provide clean burning peaking power and will help maintain the state’s comparatively low greenhouse gas emissions intensity,” he said.
In May, Origin signed a contract with GE Electric for the supply of a 120MW Frame 9E gas turbine generator set. South Australian Urban Development and Planning Minister Paul Holloway approved the development in March.