As U.S. Nuclear Plants Close, Carbon Emissions Could Go Up

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By Rebecca Kern

July 29 — Carbon emissions will rise in parts of the country when natural gas and coal plants replace electricity provided by nuclear plants that are scheduled to close, analysts and climate change experts predict.

“In the near term, emissions are going to increase,” Doug Vine, a senior energy fellow at the Center for Climate and Energy Solutions, a nonprofit, nonpartisan think tank focused on climate change, told Bloomberg BNA. He said in the past, combined cycle natural gas plants have replaced closed nuclear plants in the U.S., and “we assume that'd continue at least through the 2025 time frame.”

To date, seven plants (encompassing nine reactors) are scheduled to close between 2016 and 2025. The majority of operators say they are retiring these plants early due to difficulty competing in wholesale energy markets against record-low natural gas prices. The plants that are closing in the near future are likely to be replaced in some circumstance by generation from natural gas plants, which would lead to emission increases and could pose a difficulty meeting state and global climate goals.

Total carbon emission increases as a result of the expected seven nuclear plant closures could range from 30 million to 46 million metric tons, according to analysis compiled for Bloomberg BNA by Energy Venture Analysis Inc. and the Energy Information Administration, respectively. This would be the equivalent of annual carbon emissions from approximately 6.4 million to 10 million cars in the U.S., representing as much as 2 percent of the total U.S. carbon emissions from the electricity sector.

Nuclear plants are the largest source of zero-emission power in the U.S., producing about 60 percent of zero-emission electricity and approximately 20 percent of total electricity.

The nuclear industry says nuclear power is second to onshore wind power in terms of lifecycle carbon emissions, with 13 tons of carbon emitted per gigawatt hour compared to 12 tons of carbon per gigawatt hour for onshore wind. While the electricity generation is zero-carbon emitting, there are carbon emissions related to nuclear power that include those produced in the extraction of uranium for fuel, building the plants, and operating them with such equipment as diesel backup generators.

Seven Scheduled to Close

Exelon Corp. has announced that it will close two plants in Illinois—Clinton Power Station in Clinton in 2017, followed a year later by Quad Cities Generating Station (with two reactors) in Cordova in 2018. Exelon also will close its Oyster Creek Generating Station in Forked River, N.J., in 2019. Entergy Corp. announced last year that its James A. FitzPatrick Nuclear Power Plant in Scriba, N.Y., would close prematurely in 2017, and its Pilgrim Nuclear Generating Station in Plymouth, Mass., would close in 2019.

The Omaha Public Power District announced it will close Fort Calhoun Nuclear Generating Station at the end of 2016. Also, Pacific Gas and Electric Co. announced that it does not plan to seek another Nuclear Regulatory Commission license renewal for its Diablo Canyon Power Plant, in San Louis Obispo County, Calif., and will close its two reactors in 2024 and 2025.

Some closures, however, could be averted. In New York, for example, the Public Utility Commission's Clean Energy Standard could provide zero-emissions credits to help keep FitzPatrick plant running. The commission is scheduled to vote on a final standard on Aug. 1. Also, Exelon is discussion with Entergy to purchase FitzPatrick.

The total amount of capacity from the nine reactors expected to close, approximately 7,700 megawatts, will surpass the new nuclear generation expected to come online by 2020 from five new nuclear reactors being built in the Southeast, totaling approximately 5,600 megawatts.

Difficulty Meeting Clean Power Plan

Climate change analysts say that with the expected closure of these nuclear plants, some states may have trouble meeting state renewable portfolio standards and state emission targets set in the Environmental Protection Agency's Clean Power Plan (RIN:2060-AR33) to reduce emissions from existing power plants by 32 percent nationwide by 2030.

“In terms of state emissions and meeting the Clean Power Plan, and international agreements, because we are talking about million metric tons of [carbon], it's significant and it's sending our emissions in the wrong direction by closing these large zero-emission facilities,” C2ES's Vine said.

Emily Fisher, vice president, legal at the Edison Electric Institute, which represents investor-owned electric utilities, said her group has been worried about the potential for closing nuclear plants and reliance on carbon-emitting resources to replace the electricity they generate.

“I think there’s a general misconception that we don’t need zero-emission megawatt hours from nuclear because we can do it all with renewables, and that just isn’t true right now,” Fisher said. “So if what you care about are climate goals, and reducing emissions, then this is not the right outcome.”

One exception would be California, where Pacific Gas and Electric has announced that it plans to replace Diablo Canyon with zero-emitting resources, primarily renewables and energy efficiency. The utility has about eight years to prepare for these replacements. In other states, electric utilities don’t have as much time to prepare, and so increasing natural gas capacity may be fastest option, Fisher told Bloomberg BNA.

States that choose that option would either build new natural gas plants or rely on excess capacity from existing plants.

Building new plants would not affect a state's Clean Power Plan compliance because the regulation only affects existing units. The Clean Power Plan, however, has been stayed by the Supreme Court until litigation is completed, and states are not required to comply with it in the meantime. A federal appeals court will hear oral arguments on the legality of the regulation in September.

Implications for Paris Agreement

Vine said that the closing units could have even greater impacts on the ability of the U.S. to meet its target to reduce carbon emissions by 26 percent to 28 percent by 2025 as it agreed to do in the Paris climate accord in 2015.

Vine said his group found that in looking at current policies in place and additional policies that have been proposed, the U.S. can only get to 22 percent carbon emission reductions by 2025 with existing policies, and the closing nuclear plants won't help.

“We need to do more, and a lot of these models are assuming we'll get these five new plants, but we're going to lose some as well,” Vine said.

Fisher agreed that closing nuclear plants will have implications for overall U.S. compliance with the Paris agreement, because the U.S. pledge takes into consideration both new and existing power plants.

Another consideration is a projection by the Energy Information Administration and other analysts that natural gas prices will increase from lows of $2 per million BTU to as high as $3.20 per million BTU next year. This could lead regional transmission operators to rely on coal plants instead if their prices are cheaper than natural gas.

“As prices of natural gas go up, less gas is used and more coal generation from plants that are marginal plants,” Stephen Thumb, a principal at the Energy Venture Analysis Inc., told Bloomberg BNA.

Historical Examples of Emission Increases

There are examples of nuclear plants closing in the past, and carbon emissions rising in those regions. For example, after Southern California Edison officially closed its San Onofre Nuclear Generating Station in Pendleton, Calif., in 2012, in-state carbon emissions in the electricity sector increased approximately 10 million metric tons, or 24 percent, the following year. The electricity was replaced with renewable resources and natural gas generation, Vine said, according to data from the California Environmental Protection Agency.

Likewise, Entergy's Vermont Yankee Nuclear Power Plant in Vernon, Vt., closed in 2014, and as a result, carbon emissions in the electricity sector increased approximately 1.4 million metric tons, or 5 percent, from 2014 to 2015, according to Marcia Blomberg, a spokeswoman for ISO New England, which operates the electric grid across the six New England states.

There have been similar emission increases across the globe after nuclear plants have closed. For example, in Japan, after the Fukushima Daiichi nuclear reactor disaster occurred in March 2011, the Japanese energy-related carbon emissions increased nearly 10 percent from 2010 to 2013 after the government progressively shut down its nuclear reactors, Vine said.

Similarly, Germany had 17 reactors before Fukushima, and then shut down eight reactors in March 2011. The country's emissions had been steadily declining since 1990, but have been essentially flat from 2010-2015, Vine said. They increased from 2012 to 2013, fell in 2014 and were up again slightly in 2015.

Different Regional Impacts, Common Threads

Energy analysts and representatives of the nuclear industry project that the replacement generation mix for nuclear plants could vary by state and each regional grid operator that oversees the electric grid in that area.

“You’ll see they’re not always replaced by generation in that state,” energy analyst Chris MacCracken a principal at ICF International, told Bloomberg BNA. “Some generation will be replaced by increased imports. You could have some ramping up of existing capacity, and more incentive for new capacity from gas and renewables.”

Revis James, the vice president of policy planning and development at the Nuclear Energy Institute, which represents the nuclear industry, told Bloomberg BNA: “Each of these plants is unique. The states are different, the policies, the economics are different, but basically there are some very common threads.”

“The first common thread is when these do close, you lose a very significant portion of regional electricity generation and it has to be replaced, either entirely or partially. Some states are counting on being able to conserve electricity consumption, so they don't have to replace all of it,” he said. “But when you look at what power replaces the output from these closed nuclear units, it's unpredictable, but very often, it's replaced by a significant amount of natural-gas fired generation.”

While James said natural gas generation emits much less carbon dioxide than coal, it still emits approximately 1,000 pounds of carbon dioxide per megawatt hour. “So basically you go from zero [emissions] per megawatt hour to a significant amount, so you see an increase in emissions over time in these areas where these units have closed,” he said.

California's Diablo Canyon is the exception in that it has the longest time horizon to plan to integrate renewables, battery storage and energy efficiency mechanisms to make up for the lost capacity from the nuclear plant.

“The real benefit of long-term planning is threefold: to maintain the reliability of the system, to actually achieve the state's carbon goals so we don't increase emissions, and the third is to keep costs affordable for customers,” Todd Strauss, senior director of energy policy, planning and analysis at Pacific Gas & Electric, which owns Diablo Canyon, told Bloomberg BNA.

He said if the company didn't do long-term, orderly planning, there could potentially be reliability risks to the system. He said when utility operators have a shorter time to plan the closing, there are fewer options to replace the generation from nuclear.

To contact the reporter on this story: Rebecca Kern in Washington at

To contact the editor responsible for this story: Larry Pearl at

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