Western Australia has flagged an expansion to its energy grid to support a future influx of renewable generation needed to support heavy industry, with the state government allocating more than $120 million to the reform in this week’s budget.

Energy Minister Bill Johnston on Tuesday announced the state would begin the planning process to expand the South West Interconnected System (SWIS), foreshadowing more than 4000 kilometres of new transmission lines would be required within 20 years.