A $1.5 billion project that would allow Mallee solar farms to feed the South Australian and NSW energy grids has cleared a key hurdle.

The proposed electricity "interconnector" – running from SA's Robertstown to Wagga Wagga, through Buronga – had its business case ticked off last week by the Australian Energy Regulator.

Included in the proposal was a link between Buronga and Red Cliffs, allo...