Diablo Canyon Nuclear Closure Plan: An Important Model

Fourteen U.S. nuclear reactors have now been shut down or their owners have announced their closures since 2010, either because they were uneconomic in today’s electricity markets or had operational or environmental problems. The Joint Proposal announced yesterday for the two reactors at California’s Diablo Canyon Power Plant is historic, because it is the first time any utility owner has committed to a plan to replace retiring nuclear generation with 100 percent, zero-emissions, clean electricity-generating resources that are also lower cost. This shows that with careful planning, there is no need to substitute polluting fossil fuels for retiring nuclear generation –-an important model for the rest of the world.

The Diablo Joint Proposal signed by Pacific Gas & Electric (PG&E), Friends of the Earth, NRDC, labor and other environmental groups is further proof that our energy system is changing, and renewable energy and other resources can fill the gaps left from shuttering nuclear plants.

Energy efficiency, wind, and solar address climate change without nuclear energy’s burdens of highly radioactive waste, the need for physical and cyber security to guard against terrorist nuclear threats, the risk of radiation release in a major accident, and the nuclear weapons proliferation problem.

To see just how monumental the Joint Proposal for Diablo is, it’s important to take a look at what’s happening today in the nuclear industry. Since 2010, across Vermont, Massachusetts, New York, New Jersey, Florida, Illinois, Wisconsin, Nebraska and California, 14 nuclear reactors at 11 power plants totaling 11.9 gigawatts of electric capacity have either closed, or their owners have announced they will close.

Information on these closed or closing nuclear reactors is summarized in this table, and patterns are evident. Three of the reactors closed for primarily mechanical/safety reasons, whereas 11 reactors closed or will close primarily for market reasons. In other words, in today’s wholesale electricity markets (which largely do not reflect external costs imposed by carbon pollution), these reactors were unable to compete with other forms of electricity generation, including natural gas and wind, when utilities are procuring energy sources to help meet their customers’ needs.

The agreement between the state of New Jersey and Exelon for Oyster Creek’s closure in 2019 also had an important environmental reason – to stop the damage to Barnegat Bay from the nuclear plant’s cooling water. Of the 11 reactors closing for market reasons, all but three (Nebraska’s Fort Calhoun and Diablo’s two reactors) participate in deregulated energy markets. In eight instances, the closed or closing reactor is the only nuclear reactor at the plant (nuclear facilities with single reactors are less cost-efficient to operate than multiple reactors).

Meanwhile, eight of the 14 reactors had already completed the costly, time-consuming process of obtaining an operating license renewal of 40 to 60 years from the U.S. Nuclear Regulatory Commission (NRC). In total, the owners of these 14 closed or closing reactors have given up the opportunity for a staggering 153.9 years more of licensed operation.

Removing the 14 reactors from the energy landscape , leaves another 85 nuclear reactors currently operating at plants in 27 states. But between now and 2050, the closure of many of them is unavoidable due to the aging of these plants, which were mostly designed and constructed in the 1960s and 1970s. Moreover, the majority of the NRC operating licenses for these plants, even with extensions, will have lapsed by 2050.

A carbon-free, renewable future

Fortunately, both the United States and the world are making great strides forward on carbon-free energy efficiency and renewable energy, as well as technologies like demand response and battery storage.  An October 2015 NRDC report “Tectonic Shift” describes how economic growth is now decoupled from energy usage, and that in fact energy usage is flat. California has adopted a requirement that half of its electricity come from renewable energy resources by 2030, and New York is about to adopt the same requirement. In 2015, in data compiled by AWEA, more than 30 percent of Iowa’s electricity came from wind power alone and three other states generated more than 20 percent of their electricity from wind power alone.

And the National Renewable Energy Laboratory has concluded that “renewable electricity generation from technologies that are commercially available today, in combination with a more flexible electric system, is more than adequate to supply 80 percent of total U.S. electricity generation in 2050 while meeting electricity demand on an hourly basis in every region of the country.”

While these clean energy achievements and forecasts are remarkable, human society will still need to increase significantly the rate at which fossil fuel use is replaced by zero-greenhouse-gas-emitting energy resources.

The EPA’s Clean Power Plan, scheduled to go into effect in 2022 despite the current temporary Supreme Court stay, will establish the first-ever carbon pollution limits for existing fossil fuel power plants, providing further incentives for energy efficiency and renewable energy – as well as for new or uprated nuclear power stations. Some states, like California and the nine Northeast states, already have carbon limits in place for the electricity sector.

Today, the amount of carbon emitted into the atmosphere as a result of closing a nuclear plant depends both on whether and to what extent new power generation must be built to replace the nuclear facility and on the type of fuel chosen to substitute for the nuclear plant’s uranium.  If fossil fuel generation is substituted for nuclear power, carbon emissions will increase.

But the Diablo Canyon proposal shows that given sufficient time to prepare, retiring nuclear capacity can transition smoothly to a mix of energy efficiency measures; clean, renewable resources; and energy storage without any role for fossil fuels – an outcome that can be optimal for the environment, the market, and the reliability of the electric grid.

The Joint Proposal governing the shutdown of Diablo Canyon within nine years is exactly that – full replacement of retiring nuclear generating capacity with lower cost, zero-carbon resources. The proposal is a robust model of planned, orderly transition that takes into account sound energy policy, the values of jobs and community, the threat of climate change, and nuclear safety concerns. 

About the Authors

Matthew McKinzie

Senior Scientist, Land & Wildlife program, and Director, Nuclear program

Join Us