Transgrid has appointed Downer to its delivery panel for high-voltage infrastructure works across New South Wales, with a focus on transmission lines, substations, and transformer upgrades.

The agreement runs for an initial three years, with options to extend for another three. Under the deal, Downer will be invited to tender for individual electricity infrastructure projects -- including major transformer installations and substation construction -- valued at up to $500 million each.

Luke Sullivan, Downer's Chief Operating Officer for Energy & Utilities, said the company is one of the few Australian-owned Tier 1 contractors active in both transmission and renewables.

"With over 50 years in the transmission industry, Downer has deep capability in delivering high voltage line work, as well as complex substation and transformer upgrades," Sullivan said.

Downer will also support early-stage project planning and play a role in panel governance. The partnership includes a commitment to engage Aboriginal and Torres Strait Islander enterprises and local suppliers wherever possible.

The agreement strengthens a two-decade relationship between the two companies and forms part of Transgrid's broader program to modernise the grid and support renewable energy integration across NSW.