Environmental initiatives at coal-fired power plant

Millmerran Power is a two-unit generating station located near the town of Millmerran in south-west Queensland. It supplies enough electricity to power approximately 1.1 million homes. A base-load power station, the plant produces power at optimum levels for 24 hours every day. Coal for the power station comes from the adjacent open-cut coal mine.

The plant has been acknowledged for its efficient power generation and water conservation, through its recent selection as a finalist in the national Banksia Environmental Awards for Eco Innovation and Water.

Situated in a water-conscious area, the plant's environmental initiatives project has given particular focus to water-saving initiatives to reduce daily water consumption including:

• Water-saving cooling technology - Unlike conventional coal-fired power stations, which use large wet cooling towers, the plant uses fans, rather than water, to cool steam. This Air Cooled Condenser technology reduces water consumption by 90%, saving up to 15 ML of water each day.
• No ground or surface water used - The plant does not use any ground or surface water.
• Treated effluent used as production water - The plant uses treated effluent, from Toowoomba's Wetalla Sewerage Plant, as production water for its boilers.
• Run-off water trapped and recycled - A number of technologies ensure the plant's run-off water does not feed into local water catchments. All run-off water is kept on site via drainage channels and dams. This water is then recycled for dust suppression and watering vegetation.
• Dust impact reduced - Fully-enclosed conveyors ensure the area's surface water is not damaged by dust emissions and sediment.

Another area of focus is the reduction of CO2 emissions. Environmental technologies used to achieve this include:

• Boiler technology requiring less coal - The supercritical boilers require less coal than conventional boilers to generate the same amount of energy. This means a 10% reduction in CO2 emissions and a reduction of sulfur emissions.
• Low nitrogen burners - The plant uses low nitrogen burners resulting in 50 to 70% less nitrogen oxide emissions than conventional power stations.
• Tree planting - 60,000 trees have been planted on site to help offset greenhouse gas emissions and to aid research in hardwood tree species.

Other environmental initiatives undertaken include:

• The return of all waste ash from the combustion process to the open-cut coal mine to be buried as part of the rehabilitation of the mining area, thus eliminating the need for an ash storage dam.
• A 2 km buffer zone around the plant to minimise the impact on the surrounding community; and
• Funding of a recycled wastewater program to irrigate Millmerran golf course.

"InterGen is very proud of the outcomes achieved locally at Millmerran Power, but we are especially proud that the project has set new benchmarks for coal-fire power stations throughout Australia and internationally," said Mr David Nelson, CEO InterGen Australia.