Cooling Water
This section provides facts on how cooling water is drawn from the environment. It also describes how the flow and temperature are monitored and controlled before the water is returned to Lake Macquarie.
Canal
Cooling water is drawn from Lake Macquarie at Bonnells Bay through a canal system designed to protect the surrounding environment and wetlands.
A prefabricated concrete tunnel called a caisson measuring 260 meters long carries water under Dora Creek without disturbing the creeks tidal flow. A viaduct was also constructed to allow normal tidal flow from Muddy Lake into Lake Eraring.
Rotating screens remove debris and marine life which discharges into a settling pond where the marine life can then make their way back to Lake Macquarie unharmed.
The University of New South Wales in conjunction with Eraring Energy helped design the settling pond to maximise the survival rate of marine life. A turtle embayment has been constructed which permits the turtles to solar bask.
Temperature
Water quality is monitored continually in the inlet and outlet for water flow and temperature. The natural temperature of Lake Macquarie ranges between 13oC and 28oC. The Station has a limit of 35oC at the outlet which is monitored 24 hours a day with a audible sounding if the temperature nears the limit. To help with monitoring satellite images are taken to show the different temperature profiles with Lake Macquarie.
After the lake water is used to cool the boiler water it is returned back to Lake Macquarie through a tunnel starting in the Eraring Power Station and finishing at Myuna Bay, where a temperature monitor and an oil on water detector is located.
Condenser tubing is used to cool boiler water, older power stations used chlorine to keep condensers clean. Eraring Energy has a system called taprogge that uses foam balls to clean the inside of the condensers from marine fowling. These balls are collected and reused a number of times. If any should escape they are inert and harmless to the environment. Ferrous chloride is used to coat the condenser tubes with iron to assist in preventing marine growth inside the condenser tubes.