A study by MIT experts looked at the environmental consequences of shutting down nuclear plants and diverting power to other sources. Even if they were renewable, the consequences would not be so good.
In the United States, almost 20% of current electricity comes from nuclear power (figures very similar to Spain, which has 20.8%). The US has the world’s largest nuclear array, with 92 reactors spread across the country. Many of these power plants have been in operation for over half a century and are nearing the end of their expected useful lives. At the same time Germany has decided to close its nuclear power plants. What will be the consequences?
Those responsible for taking these measures are somewhere in between: they must decide whether to close the reactors that have already finished their cycle or strengthen their structures to continue producing nuclear energy, one that many consider a low-carbon alternative compared to the coal, oil and natural gas, determinants in the warming of the climate.
With these factors in mind, a team of MIT scientists, led by atmospheric sciences expert Lyssa Freese, has discovered that there is another factor to consider if we plan to go nuclear free: air quality. In addition to being a low-carbon source, nuclear power is relatively clean in terms of the air pollution it generates. Without nuclear power, how would the pattern of air pollution change?
Three scenarios and their consequences
Freese’s team answers these questions in a study published in Nature Energy and the conclusions are not very rosy. The authors used a power grid distribution model to assess how the US power system would respond to a nuclear power plant shutdown. The model simulates the production of all power plants in the country and is run continuously to estimate, hour by hour, the energy demands in 64 regions of the country.
To these data were added the emissions and energy costs of each plant for a whole year. They then ran the model in different scenarios, including: a grid without nuclear power, a grid without nuclear power but with renewables, and a grid similar to the current one, including nuclear power.
They combined each simulation with an atmospheric chemistry model to assess how the various emissions from each plant affect the entire country and turned that data into population density maps, allowing them to calculate the risk of premature death based on their degree of exposure. to pollutants, according to each of the three models.
The analysis showed a clear pattern: Without nuclear power, air pollution got worse overall. Without those plants, the team observed an increase in output from coal and gas plants, resulting in 5,200 pollution-related deaths across the country, compared to the current scenario.
They also calculated that more people are likely to die prematurely due to the climate impacts of increased carbon dioxide emissions, as the grid must compensate for the absence of nuclear power. The climate-related effects of this additional carbon dioxide input could result in an additional 160,000 deaths over the next century. These figures only focus on the United States and do not have to do exclusively with population. They are also linked to the proximity of the reactors and other energy production plants to urban centers, country dependency, geography and atmospheric models. Extrapolating these data to Spain without taking this information into account would not be logical.
Do renewables change anything?
However, if more renewable energy sources were available to supply the power grid, air pollution would be reduced, although not completely. The team found that even in this more abundant renewable scenario, there is still a slight increase in air pollution in some parts of the country, resulting in a total of 260 pollution-related deaths per year.
“This adds a new factor to the equation of environmental health and social impacts when thinking about nuclear shutdowns, where the conversation often turns to local risks due to accidents and mining or long-term climate impacts,” Freese explains in a statement –. In the debate about keeping nuclear power plants open, air quality has not been the focus of that discussion. What we found was that air pollution from fossil fuel plants is so damaging that anything that increases it, such as a nuclear shutdown, will have substantial impacts. We need to think about how we are retiring nuclear power plants. Closing something that has no direct emissions itself can still lead to increases in emissions, because the grid system will respond. Otherwise, we will have a reduction in air quality that we did not necessarily count on.”
