Shutting down nuclear reactors could cause over 5,000 premature deaths due to more polluting energy sources filling the gap, researchers have said.
Researchers at the Massachusetts Institute of Technology (MIT) have measured the impact that shutting down nuclear reactors could have on the environment and human health.
The team laid out a scenario in which every nuclear power plant in the US has been shut down and considered how other sources such as coal, natural gas and renewable energy would fill the resulting energy needs throughout an entire year.
Their analysis reveals that air pollution would increase, as coal, gas and oil sources ramped up to compensate for nuclear power’s absence. According to the researchers, this would have serious health effects, resulting in an additional 5,200 pollution-related deaths over a single year.
This scenario could be avoided if more renewable energy sources become available to supply the energy grid. However, even in this scenario, the team still predicted a slight increase in air pollution in some parts of the country, resulting in a total of 260 pollution-related deaths over one year.
“In the debate over keeping nuclear power plants open, air quality has not been a focus of that discussion,” said Noelle Selin, a professor at MIT’s Institute for Data, Systems, and Society (IDSS).
“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.”
To make the predictions, the team used an energy grid dispatch model developed by Jenn to assess how the US energy system would respond to a shutdown of nuclear power.
The model simulates the production of every power plant in the country and runs continuously to estimate, hour by hour, the energy demands in 64 regions across the country.
The team fed the model available data on each plant’s changing emissions and energy costs throughout an entire year. They then ran the model under different scenarios, including 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 also incorporates the additional renewable sources that are expected to be added by 2030.
Much like the way the actual energy market operates, the model chooses to turn a plant’s production up or down based on cost. Plants producing the cheapest energy at any given time are given priority to supply the grid over more costly energy sources.
The team combined each simulation 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. For populations in the path of pollution, they calculated the risk of premature death based on their degree of exposure.
The model showed that, without nuclear power, air pollution worsened in general, mainly affecting regions in the East Coast where nuclear power plants are mostly concentrated.
Without those plants, the team observed an uptick in production from coal and gas plants that would provoke 5,200 pollution-related deaths across the country, compared to the baseline scenario.
The scientists also calculated that more people are also likely to die prematurely due to climate impacts from the increase in carbon dioxide emissions, as the grid compensates for nuclear power’s absence. The climate-related effects from this additional influx of carbon dioxide could lead to 160,000 additional deaths over the next century.
“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,” said Lyssa Freese, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “Shutting down something that doesn’t have direct emissions itself can still lead to increases in emissions, because the grid system will respond.
“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”.
The researchers also looked at the populations that would be directly affected by the increased pollution. They found that Black or African-American communities – a disproportionate number of whom live near fossil-fuel plants – experienced the greatest exposure.
“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,” Selin added. “Otherwise we will have a reduction in air quality that we weren’t necessarily counting on.”
Nearly 20 per cent of electricity in the United States currently comes from nuclear power. The country has the largest nuclear fleet in the world, with 92 reactors scattered around the country, many of which are approaching the end of their expected lifetimes.
In 1985, the closure of reactors in Tennessee Valley prompted a spike in coal use, while the 2012 shutdown of a plant in California led to an increase in natural gas. In Germany, where nuclear power has almost completely been phased out, coal-fired power increased initially to fill the gap.
Last winter, UK energy firms warmed up two coal plants in preparation for an increase in the energy demand. With coal typically being the most carbon-intensive fossil fuel used for electricity generation, the UK is already planning to close all power plants that use it by 2024 as part of its efforts to meet its climate target of net-zero emissions by 2050.
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