[nerderloo]

The metric used was emission intensities: emissions per unit of generated electricity

"If coal and oil plants in the top 5 percent of polluters switched to natural gas, global emissions would drop by 29.5 percent."

So, if top 5% just switch to natural gas of the same electrical generation capacity, the global emission still drops by ~30%.

[runnerup]

https://iopscience.iop.org/article/10.1088/1748-9326/ac13f1/...

Reading the actual study, it does seem their rank for "top 5% polluting" is total emissions. They do calculate relative intensity, as you say. But the ranking for plants with greatest emissions was done without regard for capacity.

Also, the "73%" reduction would only be for GHG's from electricity-generation, not all sources.

I mean, obviously coal is a pretty awful fuel from an environmental standpoint and it's good to quantify these things. Just reading these are hard when the authors didn't necessarily make 100% clear the last few tables.

[nerderloo]

Ah, you're right. Both top 5% and top 10 plants are selected based on absolute emission amount.