STOP-GAP generators are on the way back to Nelson Bay as Energy Australia grapples with a network which is trying to meet exploding electricity demand across Port Stephens.

As well, the authority has confirmed work should begin on the long-awaited Tomaree sub-station at Nelson Bay next March and another for Brandy Hill near Seaham early next year.

The total cost of both stations is $53million.

The first of two large generators has been trucked into the Port and will be set up next to Port Stephens Council's work depot at Nelson Bay.

The generator is expected to be online within two weeks, with the second to be commissioned for summer 2010.

Two generators had previously been installed at the Bay by Energy Australia but were taken away two years ago after an additional electrical line was added to the Frost Road substation.

Growing demand exceeded the expectations of the authority, however, and plans were made for earlier construction of a planned $28 million substation.

Energy Australia engineering manager Geoff Lilliss said the generators would remain in the Port until late 2011 when work on the Tomaree substation was expected to be completed.

He said the addition of the generators, along with a thermal camera, able to pick up the cause of any line disruptions, would help ensure the network would aim to deliver a safe and reliable electricity supply during the hottest part of the year.

Mr Lilliss said the area's demand for electricity had continued to grow by more than double the average across the network and with Port Stephens Tourism predicting a bumper holiday season, every initiative was being taken.

"The network is designed to meet demand ... but we've decided to add extra backup during the busy summer period that can be used if we do experience a problem on one of the major power lines," he said.