ORIGIN Energy says it will repair an extensively damaged generator at its Mortlake power station by December 20.
On Monday morning emergency services were called to an electrical fault at the site.
The Country Fire Authority returned operational control to Origin within three hours, with no harm to Origin employees people or the community.
The power station continues to operate with the remaining generator available to supply the grid.
Origin has informed the Australian Energy Market Operator that it expects to bring the unit back online by December 20.
Origin executive general manager of energy supply and operations Greg Jarvis said the company would "work with the market operator and our suppliers with the aim of making the damaged unit available ahead of the summer peak and to reduce the impact on customers."