Women wear masks as haze from smog caused by air pollution hangs over the Forbidden City in November in Beijing.  (Kevin Frayer/Getty Images)

Electricity generation is the single biggest source of human-caused greenhouse gas emissions in the world — which is why there’s such a global effort to cut down on power plant emissions and expand alternative energy sources. And when it comes to power plants, research suggests that there may be new and more effective ways to tackle emissions in the future.

A new study in the journal Scientific Reports examines the issue of “disproportionality” in fossil fuel-burning power plant emissions — the idea that some plants produce a heftier share of a nation’s total electricity-based emissions than others.

“Disproportionality is thinking about how much inequality there is in responsibility across different facilities in terms of how much they’re contributing to overall pollution levels,” said Andrew Jorgenson, a sociologist at Boston College and the study’s lead author. “So the more uneven the responsibility is across facilities, the more disproportionality there is.”

The new report suggests that greater degrees of disproportionality in power plant emissions may be associated with greater overall amounts of national carbon emissions. And it also suggests that slashing emissions from the plants that produce the most emissions — instead of trying to cut emissions from all plants evenly across the board — may be an effective alternative way to approach climate mitigation.

The study builds on previous research by the late sociologist William Freudenburg, whose work suggested that “within different sectors of the economy … it’s likely that a small number of plants or factories are likely to be responsible for the lion’s share of that entire sector’s pollution,” according to Jorgenson.

“On the one hand, it’s kind of an obvious idea,” Jorgenson added. “It’s very likely that there’s probably some [facilities] that are the big polluters — and if so, shouldn’t we think about effective strategies if we’re concerned with reducing pollution of any kind?”  

He and two colleagues, coauthors Wesley Longhofer of Emory University and Don Grant of the University of Colorado at Boulder, decided to focus on the electricity sector, given its massive contributions to global greenhouse gas emissions. They drew on a database of nearly 20,000 fossil fuel-burning power plants — relying on coal, gas or liquid fossil fuels — in 161 nations around the world.  

Using information on each plant’s carbon output, they estimated the degree of disproportionality in power plant emissions on a national level. In other words, they determined the degree to which the amount of emissions produced by power plants in any country were similar or different. Nations with power plants producing very different levels of emissions — for instance, nations that had a few power plants with very high carbon output, while the rest produced lower levels of emissions — would have a greater degree of disproportionality than nations whose power plants mostly all produced similar levels of emissions.  

These differences can exist for a variety of reasons. According to Jorgenson, the type of fossil fuels being burned by different plants is one major factor. And the technology being used in any given plant — and how new or outdated the systems are — can also affect emissions, even in plants that are otherwise similar.

Perhaps not surprisingly, the researchers found that every nation had some degree of disproportionality — but the exact amount differed greatly from one country to the next. Additionally, Jorgenson pointed out that the researchers found that the size of the plants studied was not the driving cause behind the disproportionality.

“It’s really important to emphasize that this isn’t just about bigger power plants that generate more electricity being these egregious polluters,” Jorgenson said. Rather, after controlling for larger and smaller plants (which will produce different levels of emissions just based on their size), the disproportion still existed.

Perhaps most important, the researchers investigated the relationship between disproportionality and overall electricity-related emissions in any country. They found that there was a link. Their analysis suggested that a 1 percent increase in disproportionality leads to a 0.37 percent increase in overall national-level carbon emissions from fossil fuel power plants.

This is an important finding, according to Jorgenson, because it means that tackling just the few, biggest carbon emitters among a nation’s power plants — which are typically those contributing to the inequalities in power plant emissions on a national level — can be an effective climate change mitigation strategy.  

There are several benefits to this kind of approach, according to Thomas Dietz, a sociologist and environmental policy expert at Michigan State University.

“The suggestion that comes from these results is that instead of targeting all power plants in a country, one could get big reductions with relatively less cost by targeting the most inefficient plants,” he told The Washington Post by email. “The same line of analysis suggests that one could look carefully at the plants that are doing very well and learn lessons from them to apply to other plants and new plants.  That is, one could learn why some plants do a really good job and some do a bad job.”  

Still, studying these types of inequalities doesn’t actually pinpoint which plants are the worst offenders — it just tells us that the disproportion exists. So there’s plenty of work to be done, even after conducting a study of this type, when it comes to figuring out which plants to target.  

“To target the worst plants, one might want to do what we do with CEO salaries — compare the biggest numbers, the worst plants, to the average ‘worker,’ or the best plants, to see how bad the worst are,” Dietz suggested. “Given the data they have, it should be easy to find the plants to look at. But at that level, it would be best to be in discussion with interested and affected people and business to develop a fair and effective plan.”  

Jorgenson also pointed out that it’s possible countries with low levels of disproportionality can still have overall high electricity-related carbon output if all the plants are producing large amounts of emissions — a point he says is important not to overlook. In general, focusing future studies on particular nations can help answer additional questions about any one country’s power plant emissions, how they differ across regions, why they differ from one another and how they contribute to overall national greenhouse gas emissions.

“The more we scale this down, perhaps the more effective it could be in coming up with reasonable and effective mitigation strategies,” Jorgenson said.

And, of course, improving the power sector in one nation has benefits that radiate all over the world. While cutting down on the most egregious polluters in any area comes with multiple local benefits — cleaner air, more efficient and cost-effective electricity production — the authors’ particular focus in conducting the study was helping to aid in global climate efforts.

“We see this is as a potential double- or triple-dividend beneficial approach,” Jorgenson said. “[But] it’s clearly and fundamentally for us about climate change mitigation.”