The Queensland government will commit $5 billion to take control of and build the CopperString electricity transmission project that will expand the National Electricity Market from Townsville to Mount Isa.

In the biggest expansion of the energy grid in decades, Queensland Premier Annastacia Palaszczuk will on Tuesday formally announce plans to take over the 1100-kilometre project that will unlock a key renewable zone near Hughenden and connect major industries in Mount Isa.