The pollution intensity of Australian power stations: a case study of the value of the National Pollutant Inventory (NPI)

This paper presents a comprehensive analysis of the pollutant emissions from electrical generation facilities reported to Australia’s National Pollutant Inventory (NPI). The data, in terms of pollutant intensity with respect to generation capacity and fuel source, show significant variability. Based on reported data, the dominant pathway and environmental segment for emissions is point-source air emissions. Surprisingly, pollutant emissions from power stations are generally a very small fraction of Australia’s facility and diffuse emissions, except for F, HCl, NOₓ, PM₂.₅, SO₂ and H₂SO₄ (where it constitutes between 30 and 90 % of emissions). In general, natural gas and diesel facilities have higher organic pollutant intensities, while black and brown coal have higher metal/metalloid pollutant intensities and there is a wide variability for inorganic pollutant intensities. When examining pollutant intensities with respect to capacity, there is very little evidence to show that increased scale leads to more efficient operation or lower pollutant intensity. Another important finding is that the pollutant loads associated with transfers and reuse are substantial, and often represent most of the reported pollutants from a given generation facility. Finally, given the issues identified with the NPI data and its use, some possible improvements include the following: (i) linking site generation data to NPI data (especially generation data, i.e., MWh); (ii) better validation and documentation of emissions factors, especially the methods used to derive and report estimates to the NPI; (iii) using NPI data to undertake comparative life cycle impact assessment studies of different power stations and fuel/energy sources, or even intensive industrial regions (especially from a toxicity perspective) and (iv) linking NPI data in a given region to ongoing environmental monitoring, so that loads can be linked to concentrations for particular pollutants and the relevant guidelines (e.g., air, water, human health). Pollutant inventory systems are clearly valuable tools in understanding pollution burdens and ongoing analysis of the growing body of data should help to further improve environmental and public health outcomes. Overall, this study provides a valuable insight into the current status of pollutant intensities from Australia’s electrical generation facilities and should be a valuable benchmark for future studies and international comparisons.