Updated Hourly Emissions Factors for Chinese Power Plants Showing the Impact of Widespread Ultralow Emissions Technology Deployment

Nationwide
severe air pollution has prompted China to mandate the
adoption of ultralow emissions (ULE) control technologies at all of
its coal-fired power plants by 2020. This process has accelerated
greatly since 2014 and, combined with operational adjustments related
to overcapacity, has reduced the emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate
matter (PM). Yet the quantitative understanding of ULE benefits is
poor. Using detailed emissions data from 38 units at 17 power plants,
corresponding to 10 combinations of ULE technologies representative
of the Chinese power sector, we show that emissions factors for NOx, SO2, and PM are up to 1–2
orders of magnitude lower after ULE retrofitting. The effectiveness
in cutting emissions shows a large spread across the various ULE technology
combinations, providing an opportunity to choose the most efficient,
economically viable technology (or a combination of technologies)
in the future. The temporal variations in emissions at hourly resolution
reveal the effects of power plant load on emissions, an increasingly
important factor given that power plants are not operated at full
capacity. These data will be useful in efforts to understand the evolving
state of air quality in China and can also provide a basis for benchmarking
state-of-the-art air pollution control equipment globally.