Illawarra residents are set to trade lights for candles tonight to mark international Earth Hour.
Millions of people worldwide are expected to switch off their lights at 8.30pm, making a global pledge to support renewable energy.
Dozens of businesses in the region are also set to get behind the campaign, including the University of Wollongong, which was encouraging campuses and student residences to switch off.
Offices can participate by turning off computers, printers and photocopiers, switching lights off and unplugging phone and battery chargers when not in use.
Home owners have been encouraged to turn off TVs and stereos, airconditioning units and fans.
Shellharbour City Council is encouraging residents and businesses in its area to get involved.
"There are a number of ways people can reduce their environmental footprint and using less electricity is a good start," Mayor Marianne Saliba said.