Nuclear power has provided about 20% of electricity in the USA. Yes, this country is the home of the largest nuclear fleet in the world, hosting 92 reactors around the country. For over 50 years, these plants have given US citizens power, but they’re nearing their expected lifespans.

There are uncertainties about the continuity of nuclear energy and also if the reactors should be stopped. Conflicting opinions mostly come from the consideration that nuclear is a lower-carbon alternative to the conventional coal, oil, and gas.

This is where new research from the Massachusetts Institute of Technology (MIT), which was published in Nature Energy, can help with weighing the options.  

According to the researchers, there’s another factor when it comes to deciding the future of nuclear power: air quality.  Study author Noelle Selin said that air quality hadn’t been a focus of discussions and debates over keeping nuclear power plants open.

“What we found was that air pollution from fossil fuel plants is so damaging, that anything that increases it, such as a nuclear shutdown, is going to have substantial impacts, and for some people more than others,” Selin said.

Nuclear gives us cleaner energy and, in turn, cleaner air.  If we took it away completely, what exactly could happen to the air and what other things that would happen?

Examining what had happened before

Based on the questions, the MIT researchers explored cases where every nuclear power plant in the country has shut down, and consider how other sources such as coal, natural gas, and renewable energy would fill the resulting energy needs throughout an entire year.

The team found that, in current times, the shutting down of nuclear power would increase air pollution, as coal, gas, and oil sources ramp up to compensate for nuclear power’s absence. 

They looked at the time when nuclear power had closed in the past. In 1985  Tennessee Valley, closure of nuclear reactors resulted in a spike in coal use. During the 2012 shutdown in California, people began using more natural gas. And in Germany, where nuclear power has almost completely been phased out, coal-fired power increased initially to fill the gap.

After noticing these trends, the MIT team wondered how the U.S. energy grid would respond if there were no nuclear power.

According to lead author Lyssa Freese, “We wanted to think about what future changes were expected in the energy grid. We knew that coal use was declining, and there was a lot of work already looking at the impact of what that would have on air quality. But no one had looked at air quality and nuclear power, which we also noticed was on the decline.”

 

 

Using a simulation model

The MIT team used an energy grid dispatch model developed to assess how the US energy system would respond to a shutdown of nuclear power. With this model, the researchers simulated the production of every power plant in the country. They also ran the model continuously to hourly estimate the energy demands in 64 regions across the country.

Unsurprisingly, similar to what can happen in real life, the model chooses to turn a plant’s production up or down based on cost. Whichever plant produces the cheapest energy, they become the prioritized energy source to supply the grid.

The model was fed available data on each plant’s changing emissions and energy costs throughout an entire year. 

Afterwards, the team ran the model under different scenarios which include an energy grid with no nuclear power, a baseline grid similar to today’s that includes nuclear power, and a grid with no nuclear power that incorporates the additional renewable sources. The last one was added to simulate renewable energy plans expected to be added by 2030 in the US.

Each simulation was then combined with an atmospheric chemistry model to simulate how each plant’s various emissions travel around the country and to overlay these tracks onto maps of population density. 

Populations in the path of air pollution were also within the model’s calculation, particularly the  risk of premature death based on their degree of exposure.

Since nuclear energy is cleaner, it’s not a big reveal that, in the study, the team found more air pollution if they’re phased out. Such pollution alone can result in  an additional 5,200 pollution-related deaths within a single year.

Air pollution caused by oil and gas already a problem

Another study which was published in the journal Environmental Research: Health and led by Boston University School of Public Health (BUSPH) found that gas and oil consumption in the US has led to adverse impacts on air quality, human health, and health costs. 

The researchers found that pollutants  from U.S. oil and gas production contributed to 7,500 excess deaths, 410,000 asthma attacks, and 2,200 new cases of childhood asthma across the US in 2016.

Furthermore, the air pollution is associated with respiratory and cardiovascular-related hospitalizations, adverse pregnancy outcomes, and other health challenges. In total, it’s responsible for $77 billion in annual health costs–three times the estimated climate impact costs of methane emissions from oil and gas sectors.

 

 

Not only affecting nearby areas

States such as Texas, Pennsylvania, Ohio, Oklahoma, and Louisiana are the most impacted regions because they’re within environments with significant oil and gas operations. 

However, the BUSPH research discovered that the health effects extended into other populated cities with little or no gas activity such as Chicago, Baltimore, Washington DC, and Orlando. Additionally, Illinois and New York, which produce very little oil and gas, still got the 6th and 8th spots of the highest impacts from the air pollution.

This study senior author Saravanan Arunachalam said, “The fact that air pollution and health impacts cross state boundaries indicates a strong need for regional to nationwide coordination.”

So, as we can see, air pollution it’s already an ongoing issue in the country.

Unwise to turn nuclear power off now

Now, from the MIT research, we can see a pattern. When we lose nuclear power, air pollution generally gets worse, and the negative impact is prominent in regions in the East Coast–an area concentrated with nuclear power plants.

When those plants were gone, in the developed model, the research team saw an increase in pollution-related deaths across the country, mainly due to the uptick in coal and gas production. To be specific, the climate-related effects from this additional influx of carbon dioxide could lead to 160,000 additional deaths over the next century.

Freese said, “We need to be thoughtful about how we’re retiring nuclear power plants if we are trying to think about them as part of an energy system. Shutting down something that doesn’t have direct emissions itself can still lead to increases in emissions, because the grid system will respond.”

To prevent the considerable number of predicted deaths, the MIT researchers proposed increasing renewable energy sources to supply the energy grid as soon as possible. With the current US renewable energy plan expected by the year 2030, the team suggests that air pollution will still be there, but it’s not gonna be too concerning.

“This might mean that we need to deploy even more renewables, in order to fill the hole left by nuclear, which is essentially a zero-emissions energy source. Otherwise we will have a reduction in air quality that we weren’t necessarily counting on,” Selin added.

But to sum everything up, the MIT researchers believe that the phasing out of nuclear energy must put air pollution and its consequences into consideration. 

“This adds one more layer to the environmental health and social impacts equation when you’re thinking about nuclear shutdowns, where the conversation often focuses on local risks due to accidents and mining or long-term climate impacts,” Freese said.

 

Sources

https://www.sciencedaily.com/releases/2023/04/230410111700.htm 

https://www.sciencedaily.com/releases/2023/05/230508114018.htm