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Emissions monitoring at Liddell and Bayswater power stations.

Tim Nelson
Tim Nelson
15 May 2017

AGL acquired Liddell and Bayswater power stations in September 2014, and cannot comment on operational practices prior to that date.

Liddell and Bayswater power stations operate in compliance with licence conditions set by the NSW EPA, Protection of the Environment (Clean Air) Regulation 2010 and national air quality guidelines.

Since acquisition in September 2014 AGL has proactively invested to improve emissions monitoring and reporting standards at Liddell and Bayswater power stations.

By 30 June this year all 8 generating units at Liddell and Bayswater will have 24 hour real time emissions monitors in operation.

AGL uploads the results from real time emissions monitoring at Liddell and Bayswater power stations to its website monthly.

Bayswater power station

The current Bayswater power station NSW EPA Environment Protection Licence requires stack emissions monitoring and testing from each generating unit once per annum. Bayswater has four generating units.

This testing involves monitoring for the pollutants specified in Condition M2.2 of the Bayswater Environment Protection Licence, and in accordance with the required sampling methods specified in Condition M2.2.

The Bayswater Environment Protection Licence also requires continuous monitoring of particles from all four generating units, and continuous monitoring of nitrogen oxides (NOx) and sulphur dioxide (SO2) for Unit 1.

Shortly after acquisition of Bayswater power station in September 2014, AGL Macquarie identified an opportunity to improve emissions monitoring and reporting.

A commitment was made to voluntarily install ‘real time’ Continuous Emissions Monitors (CEMS) for NOx and SO2 on the remaining three Bayswater generating units, 2, 3 and 4.

The new CEMS will operate 24 hours a day, every day of the year. The units will continue to be subject to annual stack emissions testing to verify and validate the accuracy of the CEMS equipment.

The new CEMS will be commissioned and in operation by the end of June 2017, and will be added to the Bayswater power station Environment Protection Licence.

In addition, in 2015 AGL Macquarie installed real time oxygen monitors on unit 1 at Bayswater power station, which is the unit currently used for NOx and SO2 CEMs. This enables improved monitoring of real time NOx and SO2 emissions, as they are normalised using real time oxygen data.

The Bayswater real time emissions monitoring results, conducted as a requirement of the Environment Protection Licence, are included in a report that is uploaded to the AGL website monthly. This report also includes the annual stack emissions testing for all four units.

Liddell power station

Liddell power station has NOx and SO2 Continuous Emissions Monitors (CEMS) on all four generating units. These were in place when AGL acquired Liddell power station.

Liddell also has real time CO2 monitoring on all four units.

Real time NOx and SO2 emissions results are normalised using the real-time CO2 monitors for Liddell emissions reporting.

Normalisation using real time O2 or CO2, or normalisation using annual stack emissions monitoring for emissions reporting are both accepted sampling methods under NSW EPA standards.

Liddell power station emissions monitoring results are also uploaded to the AGL website monthly.

National Pollution Inventory and Load Based Licencing

Data from the CEMS and stack emission testing is used to calculate emissions reported to the National Pollution Inventory (NPI) and for Load Based Licence (LBL) requirements.

Emissions for substances covered by the Load Based Licencing scheme for Bayswater and Liddell have been calculated in accordance with the relevant guidelines, standards and agreed calculation methods with the EPA. The calculation methods used, estimate total emissions of NOx, SO2 and other emissions for all generating units at Bayswater and Liddell.

NOx and SO2 emissions reported under the National Pollution Inventory are calculated using several data sources. These include but are not limited to coal analysis data, CEMS monitoring data, stack emissions monitoring data, coal usage and power generation. Variations in the data that is used to calculate the emissions from year to year such as an increase or decrease in coal usage, can explain the variations in emissions reported.

Since 2015, when the oxygen monitors were installed at Bayswater power station, NOx and SO2 emissions calculated for the NPI and LBL have been normalised using the data from the real time O2 monitors. Prior to 2015 the NOx and SO2 data were normalised using the annual stack test monitoring. Whilst both methods are accepted under the approved calculation methods, using real time oxygen data for normalisation improves the accuracy of emissions reporting.

The reduction in emissions reported in the 2015/16 NPI for Bayswater are due to a number of factors such as the change in the NOx and SO2 emissions calculation method by using real time O2 for normalisation, and improvements in operational efficiencies, identified and implemented by AGL at Liddell and Bayswater, that have resulted in increased electricity generation using less coal.

Additional comments

Carbon pricing under the Clean Energy Act 2011 was repealed prior to AGL’s acquisition of Bayswater and Liddell power stations. As such Bayswater and Liddell have not been subject to a carbon liability under AGL ownership.

Power stations like Bayswater and Liddell often use coal from a number of different mines or suppliers. Coal from different mines and coal seams has varying properties.

Blending of coal can be done, at the coal mine or power station, to meet supply agreement conditions, and ensure compliance with air quality protection guidelines and EPA licence requirements. This is common practice in the industry.

Blending coal specifically for use in an individual generating unit at power stations like Liddell and Bayswater, is operationally difficult and is not practicably possible on an ongoing basis.

Coal from the same sources is used in all eight units at Liddell and Bayswater power stations.