Greenhouse gas emissions within the United States have been trending downward for the past few years, mainly because coal-fired generation is declining (see: “How and Why U.S. Greenhouse Gas Emissions Are Falling”). Coal’s decline will likely continue, given an abundance of domestic gas and the many coal plant retirements expected over the next several years.
But a new report from the Center for Climate and Energy Solutions (formerly the Pew Center on Global Climate Change) is a reminder that coal’s share of electricity is not the only one that could substantially decline in the next several years. Nuclear’s share appears likely to shrink as well, and the likely greenhouse gas emissions increase could imperil the country’s chances of meeting its pledge to reduce emissions by 17 percent relative to 2005 levels by 2020. An aging reactor fleet, cheap natural gas, renewable energy incentives, and other economic factors could lead to “a wave of U.S. reactor retirements in the coming years,” writes Doug Vine, a senior fellow at the Center for Climate and Energy Solutions.
The report notes that four reactors were retired in 2013, and another is slated to go offline this fall, representing just over 4 percent of the total U.S. nuclear capacity. Depending on how that generating capacity is replaced, these retirements alone could lead to a release of an additional 12 million to 18.25 million metric tons of carbon dioxide per year—or the same amount emitted yearly by two million to 3.6 million passenger vehicles, according to the report.
There are five new reactors currently under construction, but the first one won’t be ready until December 2015 at the earliest, and the others won’t start up until 2017 or later. In the meantime, subtracted nuclear capacity is likely to be replaced in large part by fossil fuel plants.
Nuclear power supplied 19 percent of the total electricity in the U.S. in 2012 (See “Nuclear Options”), and it accounted for 60 percent of electricity generated at plants that don’t emit carbon dioxide. Whereas the total emissions associated with nuclear power is similar to that of wind or solar power, unlike wind and solar plants, nuclear plants can run 24 hours a day, seven days a week, making them suitable to provide baseload power.
For perspective, consider this: the Center for Climate and Energy Solutions calculates that in a scenario in which nuclear power was replaced completely by fossil fuels after 2012, the added emissions between then and 2025 would be four to six billion metric tons. That’s the same amount the EPA hopes to avoid, over the same time frame, through vehicle efficiency standards.