Greetings All –We provide you with the latest installment of our ongoing energy series, Illinois Energy Transformations.We provide this fact sheet both in test below, and as an attachment, where we know the graphics will be properly placed.Feel free to contact us if you have any questions, or need additional information.Be well, –David Kraft, Director, NEIS —


“…and when the rivers don’t flow?….then what?…”

In previous installments of this series, NEIS has attempted to keep the size down to 1-2 pages max.  This issue it too important to confine to that limit.

A major paper was recently released that raises a serious performance issue for those in favor of continued use of nuclear power.  It comes at a critical time when states are debating enormous bailouts of existing nuclear plants that would delay implementation and continue the underfunding of renewable energy, efficiency, storage and transmission upgrades; and entertaining the fanciful promises of a future generation of nuclear reactors being pitched as “solutions” to the climate crisis.

The report, “Increase in frequency of nuclear power outages due to changing climate,” (Nature Energy | VOL 6 | July 2021 | 755–762 |[1] reveals the vulnerability of nuclear power plants to the extreme weather conditions of the ever-escalating climate crisis.  The Report found:

“In the 1990s, the average frequency of environment-induced outages (full and partial) was around 0.2 outage per reactor-year, but since then it has increased by around eightfold, reaching an average of 1.5 in the past decade.” (emphasis ours). [1]

“Overall this latest analysis calculates that the frequency of climate-related nuclear plant outages is almost eight times higher than it was in the 1990s… While the paper doesn’t directly link the reported events to climate change, the findings do show an overall increase in the number of outages due to a range of climate events ….A retrospective analysis further showed that for every 1°C rise in temperature (above the average temperature between 1951 and 1980), the energy output of the global fleet fell about 0.5 percent.” [2]

The report identifies two major causes for such climate-related outages:  thermal disruptions (heat, drought, and wildfire; and while not analyzed in this report, unanticipated cold as was seen in Texas in March 2021) and storms (e.g., hurricanes, typhoons, lightning, and flooding).

Years ago NEIS identified numerous heat-related events that shut down nuclear plants in its fact sheet“It’s the Water, Stupid!”  For the past 3-4 decades, heat and drought have shuttered nuclear plants worldwide.[3]  This was first called to our attention during the Illinois drought of 1988, when over 100-reactor days of operation at Exelon (then ComEd) reactors  were either severely curtailed or completely eliminated during a heat wave — when the plants were needed most. [4]  The drought had reduced river water levels and flow rates to a point where operating the reactors would have exceeded EPA standards for thermal pollution – in effect, cooking the rivers and all the plants and animals in them.  While such an extreme event has not happened since, Illinois has come very close on several occasions; and Exelon has often requested exemptions from meeting thermal limits required by EPA regulations in such circumstances.

Future prospects do not look promising for Illinois rivers, as can be seen by this chart from a Standard & Poors Global Market Intelligence [5] report released in 2020:image.png

The water and drought issue should be of great concern and analyzed in detail as the Illinois legislature – and others around the nation – are being besieged by Exelon and nuclear utilities to provide bailout money for money-losing reactors, whose reliability and continued operation are called into question in an increasingly climate disrupted world.

Drought and water availability are not the only thermal vulnerabilities. 

Reactors are programmed to automatically shut themselves down to protect sensitive equipment if the outside temperatures cause temperatures inside the reactor vessel to exceed certain values.  This occurred in 2006 at the Donald C. Cook NPP on the west shore of Lake Michigan.

The report also mentions the almost humorous reactor shutdowns caused by massive schools of jellyfish plugging up the intake pipes at nuclear reactors in coastal areas.  Hotter ocean waters are ideal for super spawning of the jellies, who then get sucked into reactor water pipes.  Seems that Mother Nature has a twisted sense of humor. Or revenge.

Storm disruptions have equally plagued nuclear plants in the past, according to the report:

“Storms and wildfires, on the other hand, caused a range of problems, including structural damage, precautionary preemptive shutdowns, reduced operations, and employee evacuations. In the timeframe of 2010 to 2019, the leading causes of outages were hurricanes and typhoons in most parts of the world….” [2]

image.pngFigure 1:  “Port” Calhoun – 2011

While the March Texas disaster may be one of the most recent examples, others are numerous.  Perhaps the U.S. poster child for storms and floods affecting reactors occurred in 2011 when the massive Missouri River flood turned the Fort Calhoun reactor in Nebraska into “Port Calhoun.”  For a month the reactor was completely surrounded by flood waters, and was accessible only by boat or helicopter.  At one point there was an actual breach of the flood barriers, which thankfully was quickly halted. 

In 2020 the damage caused by a summer derecho contributed to the decision to permanently close the Duane Arnold reactor in Iowa.

The now annual-wildfire hazards experienced in California and places out west have already demonstrated that plants may be preemptively shut down as a precaution to protect the entire grid system.  At the opposite end of the thermometer, the Texas transmission disaster of March 2021 also showed the system vulnerability to extreme cold weather, when both nuclear and fossil fuel plants were shut down.

Finally, it should be noted that as water temperature increases, the electrical output efficiency of the reactors falls.  As a 2006 paper by the Union of Concerned Scientists indicates:

“…lake, river, or ocean water temperature rising from 70ºF to 90ºF reduces the electrical output of the plant nearly five percent. As demand for electricity rises with the temperature, ability to supply drops.”[6]

While not related to water temperature but rather all climate effects on causing outages, the Report points out that,

“…for every 1 °C temperature increase above the 1951–1980 average temperature baseline, the average share of energy output lost out of the global energy generation by NPPs is increased by around 0.5%.” [1, p. 757]

“…average projected energy loss range of NPPs under a high-emission scenario is 1.4% to 2.4% in the long term (2081–2100), site-specific losses could be much higher….” [1, p. 761; emphasis ours]

To be fair, all energy resources will be uniquely affected by climate disruption mechanisms, including renewables.  The significant differences between those effects and the ones on nuclear are:

  • Unlike nuclear power and fossil fuel plants, no renewables in use or planned in Illinois will rely on water.  They will not suffer the water-related vulnerabilities already often exhibited in Illinois, which are expected to worsen.
  • While technology does exist for nuclear plants to lower reliance on water,

“…these mechanisms lower the thermal efficiency of NPPs and put a downward pressure on their already challenging economics….” [1, p. 760]

  • Renewables built will be newer than nuclear and fossil fuel plants, making them more amenable to taking advantage of technological advances to mitigate certain climate-related downsides:

“However, unlike renewable energy sources that have a relatively short lifetime, which would allow for a faster integration of technological advances into a new generation of power plants, the long lifetime (≥60 yr) of nuclear reactors limits the integration of new technology and wider design margins in a timely manner.” [1, p. 760]

  • While difficult, if necessary wind and solar farms can be relocated to adjust to changes in climate-related weather patterns.  Old nuclear plants cannot be relocated; and new ones would need to be sited carefully, but would still have the same mobility problem should weather and water conditions change.

Implications for Policy:

Current legislative proposals in Illinois have called for as much as $700 million in nuclear power bailouts for Exelon’s reactors.  The Biden Administration and certain members of Congress are calling for upwards of $50 billion over the next ten years to be allocated to nuclear power, some of which would be dedicated to bailing out old, uncompetitive reactors like Exelon’s in Illinois.

From a climate mitigation standpoint, these bailouts represent a waste of ratepayer and taxpayer money.

The current Illinois bailout proposal has failed to take into account a number of factors:

  • Exelon has announced creation of a new company that aggregates all its money-losing reactors into a new entity called “SpinCo.”  These are all aging as well as money losing-plants.  They will undoubtedly require increases in maintenance expenditures and in some cases very costly major equipment replacements, some of which have already been hinted at in documents Exelon provided to the NRC in 2013 when it requested and was granted 20-year license extensions. Since SpinCo is expected to be an LLC, there will be no financial backing available for these costly repairs and equipment upgrades. This will almost certainly require future bailouts, borne by Illinois ratepayers.
  • One proposal called for Exelon to sell off its reactors.  If Exelon cannot make these reactors profitable without bailouts, who can? And at what cost-cutting price – Safety? Maintenance? Staff?  And won’t those companies eventually be in the same position to have to request more ratepayer funded bailouts to continue operation?
  • No matter who would run these reactors, in the future, they would have to spend exorbitant amounts of money to deal with the climate-crisis realities outlined in this Report.

Clearly, there comes a time to depart from the “sunk-cost fallacy,” and cut bait.  The climate realities are forcing those choices on policy makers now.  It would be much more in the best future interests of Illinois, its ratepayers and the economy to invest in a new and more resilient energy system, created in a manner better suited to dealing with the anticipated worsening climate crisis scenarios.  It makes far more sense to invest any proposed nuclear bailout monies into state-of-the art appropriate renewables, energy efficiency, energy storage, and micro-grid and grid transmission upgrades.

Conclusions and Recommendations:

  1. “With uncertainty surrounding our ability to mitigate or slow down climate change, it is imperative to study scenarios of how the next level of global warming could impact energy systems in general and nuclear power in particular, given its advocatory role in fighting climate change in the first place.” [1, p.760]
  2. Fifty-plus legislators of the Illinois Legislative Green Caucus have signed a joint letter stating that this legislation is a climate bill, or they will not support it.  Governor Pritzker has stated it is a climate bill.  If this talk is genuine, then we can no longer ignore nuclear power’s vulnerabilities to climate disruption, its negative water impacts, and reduced efficiencies.
  3. The crude, primitive and myopic (and some would say, self-serving) political view that the upcoming energy legislation is about “jobs” is going to have to be subservient and secondary to escalating climate disruption concerns, such as those listed in this Report.

Conclusions and Recommendations: (cont’d.)

  1. While it is always easier to spend someone else’s money, good public policy would have it spent on technology that works, is resilient, and has a future – like renewable energy and efficiency.  Nuclear

power is “brittle power” without much future, and which will become increasingly vulnerable in a climate disrupted future.  Lavishing bailout money on it is a poor public policy choice.

  1. Given the continually dwindling constraints of time and money, proposed nuclear bailout money would be better spent on new renewables, efficiency, storage and transmission grid improvements to achieve the State’s stated climate goals.  This will be money spent on new state-of-the art equipment not tied to the uncertainties of water availability, rather than on aging and currently unprofitable equipment which will experience increased O&M costs the older they get.
  2. As NEIS has maintained since 2013 – bailout the workers and the affected communities, not the profitable nuclear and fossil fuel corporations.  Enact just-transitions programs for reactor and fossil fuel communities ASAP.

For a long time, nuclear power cheerleaders would taunt renewables advocates by snidely asking, “What are you going to do when the sun don’t shine and the wind don’t blow?”  As this Report solidly demonstrates, we now have to ask them, in all seriousness, “And what are YOU going to do when the rivers don’t flow, the hurricanes blow, and the sea levels (and jellyfish) grow?”

It should always be remembered:  nature bats last.


[1] — , “Increase in frequency of nuclear power outages due to changing climate,” (Nature Energy | VOL 6 | July 2021 | 755–762 |

[2] —  Nuclear power’s reliability is dropping as extreme weather increases,”, 7/24/21.

[3] – “Intense Summer Heatwaves Rattle Worlds Power Plants,” Sonal Patel, Power Magazine, 10/1/2018.

[4] — See Nuclear Regulatory Commission archived daily plant operation reports for Region III, June 1- Sept 1, 1988.

[5] – “Climate change poses big water risks for nuclear, fossil-fueled plants,” S&P Global Market Intelligence, 10/21/20.

[6] – “Nuclear HEAT,” Union of Concerned Scientists Issues Brief, 8/3/06.