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San Onofre: the fallout from closing California's nuclear plant

Last week a California utility announced it would close the San Onofre Nuclear Generating Station. That closure, along with the shutting down of other nuclear plants, will have serious consequences for consumers and slow efforts to reign in greenhouse gas emissions, Styles writes.

Half of California鈥檚 Nuclear Generating Capacity Shut Down

I鈥檓 still digesting last week鈥檚聽聽by Southern California Edison that the utility鈥檚 San Onofre Nuclear Generating Station (SONGS) in Southern California will close permanently, nine years prior to the聽聽of the facility鈥檚 operating license. The plant鈥檚 two nuclear reactors were shut down for repairs in early 2012, and the Nuclear Regulatory Commission (NRC) still hadn鈥檛 approved the company鈥檚 plan to restart them, despite a protracted review.聽Although this event is quite different from聽the 2011 Fukushima accident in Japan, its ripples are likely to extend beyond California, where both the state鈥檚 electricity market and its greenhouse gas emissions will be adversely affected.

California鈥檚 Emissions Could Increase by聽6 Million Tons per Year

Before considering how the San Onofre closures will affect the nation鈥檚 nuclear industry and generating mix, let鈥檚 focus on California.聽While accounting for only 3% of the state鈥檚聽聽from all sources, the SONGS reactors typically contributed around 8% of the state鈥檚聽, due to their high utilization rates.聽That鈥檚 a large slice of low-emission power to remove from the energy mix in a state that is聽to reduce its emissions below 1990 levels.聽

How much emissions will increase following the shutdown depends on the type of generation that replaces these units.聽If it all came from renewable sources like wind and solar, emissions wouldn鈥檛 go up at all, but that鈥檚 impractical for several reasons.聽Start with the inherent intermittency of these renewables, and then compound the challenge by its scale. Even in sunny California, replacing the annual energy contribution of the SONGS units would require around 7,200 MW of solar generating capacity, equivalent to nearly 2 million 4-kilowatt rooftop photovoltaic (PV) arrays. That鈥檚 over and above the state鈥檚 ambitious 鈥溾�� target, which was already factored into the state鈥檚 emission-reduction plans. (Read More:聽)

In fact, grid managers from the state鈥檚 Independent System Operator recently聽聽that in the near term much of the replacement power for SONGS will be generated from natural gas.聽Even if it matched the mix of 71% gas and 29% renewables聽聽from June 2012 to April 2013, based on 鈥渘et qualifying capacity鈥�, each megawatt-hour (MWh) of replacement power would emit at least聽. more CO2 than from SONGS.聽That鈥檚 an extra 4 million metric tons of CO2 per year, or 8% of California鈥檚聽聽from its electric power sector and almost 1% of total state emissions.聽If gas filled the entire gap, or if聽the natural gas capacity used was not all high-efficiency combined cycle plants, the figure would be closer to 6 million metric tons, equivalent to the annual emissions from about 1.5 million cars.

Early Retirements Offset the Benefits of the Nuclear Renaissance

The SONGS shutdown brings to four the number of nuclear reactors that have been聽closed permanently this year, reducing the operating US nuclear power plant fleet to 100 units.聽Several other plants face severe challenges, including the ongoing聽聽over the 鈥溾�� for Vermont Yankee, strong聽to the Pilgrim unit on Cape Cod, and a聽聽license renewal process for the two Indian Point units near New York City.聽The early retirement of San Onofre can only embolden the opposition to other nuclear plants.

A few years ago, when the nuclear power sector planned a large new-build program in the US, it seemed reasonable to assume that most existing plants would easily obtain 20- or 30-year license extensions, in line with well-established precedent. That would carry the bulk of the fleet into the 2040s and beyond. Meanwhile, new construction would add many gigawatts of new capacity and enable nuclear power聽to gain market share against coal and gas.聽However, between a recession that聽聽of US electricity demand and the low natural gas prices brought about by the combination of the same recession and the shale gas revolution, the economics of new nuclear power in the US have become tenuous. Some operators have even聽聽relatively low-cost 鈥渦prate鈥� projects to increase capacity at existing plants.

As part of its Annual Energy Outlook for 2013, the Energy Information Administration (EIA) of the US Department of Energy looked at聽聽for nuclear expansion or retrenchment. In addition to the four reactor retirements announced this year, Exelon Corp. has already聽聽that its Oyster Creek plant in New Jersey will shut down in 2019, after 40 years of operation.聽If聽the two Indian Point units were also shut down, then total retirements since 2012 would reduce US nuclear generating capacity of 101,400 MW by more than the 5,580 MW combined capacity of the five new reactors currently聽聽and scheduled to start up by late 2018. The difference of around 650 MW would likely be made up by natural gas.

Conclusion: Despite New Construction, US Nuclear Capacity Could Actually Shrink

Between now and 2020, despite the first new nuclear power plants in a decade coming on-line, nuclear鈥檚 contribution to our energy mix won鈥檛 grow by much, and may actually shrink. That will have consequences for consumers and for efforts to reduce greenhouse gas emissions. Retiring fully depreciated power plants that still have many years of potential operating life remaining, and replacing them with new generation of聽补苍测听technology, is bound to increase the cost of electricity in the markets where these plants have operated. And even if the net loss of nuclear capacity were directly replaced with high-reliability renewable generation such as hydropower or geothermal, that鈥檚 still that much renewable capacity not available to displace higher-emitting generation.聽Opponents of nuclear power may see that as progress, but it looks like a step backward to me.

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