What is the National Pollutant Inventory?
The National Pollutant Inventory (NPI) is part of the Commonwealth Department of Environment and Energy.
The NPI tracks pollution across Australia, and provides the community, industry and government with information about emissions to local environments.
All Australian industrial facilities that trigger the NPI reporting criteria are required to submit annual reports of their emissions and transfers of wastes. These reports are published on or before 31 March each year for the preceding financial year.
What are Liddell and Bayswater’s NPI reporting obligations?
Emissions for substances covered by the NPI for Liddell and Bayswater Power Stations are calculated according to the guidelines, standards and agreed calculation methods set by the NSW EPA. The calculation methods estimate total emissions for all substances, as required by NPI, for all generating units at the power stations.
Why do emissions reports from Liddell and Bayswater vary from year to year?
NPI emissions data can vary substantially from year to year, as the NPI process requires calculation of emissions based on stack monitoring and testing from each generating unit just once per year - a snap shot in time.
The stack emissions monitoring results can also vary substantially from year to year for several reasons, for example maintenance operations on the day, coal supply, plant performance and electricity demand.
What is AGL doing to improve emissions management and reporting at Liddell and Bayswater?
When AGL acquired Liddell and Bayswater Power Stations in September 2014, the Bayswater environment protection licence required continuous monitoring of particulates from all four generating units, and continuous monitoring of nitrogen oxides (NOx) and sulphur dioxide (SO2) on Unit 1.
Shortly after acquisition of Liddell and Bayswater Power Stations, AGL identified an opportunity to improve emissions monitoring and reporting by extending the continuous monitoring to the remaining three units.
AGL voluntarily installed ‘real time’ continuous emissions monitors (CEMS) for NOx and SO2 on the remaining three Bayswater generating units, 2, 3 and 4.
Since June 2017, the CEMS at Bayswater have been in operation 24 hours a day for NOx and SO2, and this monitoring has been added to the Bayswater environment protection licence.
Liddell Power Station also has NOx and SO2 CEMS on all four generating units. These were in place when AGL acquired Liddell.
One of the conditions of the Liddell and Bayswater environment protection licences is that AGL monitors and reports on opacity in real time. Opacity is an indicator of particulates being emitted from each of the units. Particulates and trace metals will continue to be measured by annual stack emissions testing, in accordance with the NPI reporting process. For the reasons stated, we therefore expect the NPI reporting process to continue to produce some variability in results.
The voluntary installation of CEMS however will enable us to more accurately monitor and report NOx and SO2 emissions for future NPI reports, and therefore reduce the variability seen in recent year to year reports.
In addition, we will continue annual stack emissions testing on Liddell and Bayswater units to verify and validate the accuracy of the CEMS equipment.
Emissions data for Liddell and Bayswater Power Stations is publicly available here.