When plans for the Shellharbour City Hub building were released in June, Cr Kellie Marsh criticised them over the absence of solar power.

At the time, the council said that the building included enough "environmentally friendly features", such as passive design and water-saving devices, to enable it to achieve a five-star rating from the Green Building Council of Australia.

On Tuesday night, Shellharbour councillors will be presented with a report that outlines the costs and benefits of installing solar panels, based on the "expert opinion" of consultants WSP Built Ecology.

The report said the maximum size of a photovoltaic array - 480 square metres - would cost $171,000 and reduce carbon emissions by up to 123,500 kilograms CO2.

"The addition of a solar photovoltaic cell system is not necessary for council to achieve the project objectives," the report said. "Further, the payback period of 14 years for the photovoltaic system is not financially attractive."

As the cost of the City Hub project - currently estimated at $57 million - was a "sensitive and important factor to the council", it might be prudent to await further design development for more certainty over the project's costs before any decision on solar power was made, the report said.

The project team had not ruled out solar power and was still investigating alternative methods of funding such as power-purchasing agreements.

Cr Peter Moran, who had called for the report from staff, described it as "half a response".

"I feel staff are looking at everything through the prism of a five-star rating," Cr Moran said.

"The building achieves that, but it doesn't mean we can't go beyond that."