Wind and solar are not the only generation technologies where weather conditions can impact production. "Nuclear power production in the U.S. is at the lowest seasonal levels in nine years as drought and heat force reactors from Ohio to Vermont to slow output." http://www.businessweek.com/news/2012-07-26/heat-sends-u-dot-s-dot-nuclear-power-production-to-9-year-low.
Bloomberg Businessweek goes on to state that nuclear generation was about 2,600 megawatts below the applicable average and at "94,171 megawatts or 93 percent of capacity, and the lowest level for this time of year since 2003."
At times during the summer, Vermont Yankee has had to reduce output to 83 percent of capacity, and two Exelon plants in Illinois cut power to 80% and 84%. So what is the problem?
Bloomberg quotes David McIntyre, an Nuclear Regulatory Commission spokesman stating: "Heat is the main issue, because if the river is getting warmer the water going into the plant is warmer and makes it harder to cool."
As Prof Muller documents (see yesterday's posts), the heat is not going away but will intensify in the coming years. Temperatures are up 2.5 degrees in the last 250 years, with 1.5 degrees in the last 50 years, and Muller expects another 1.5 degree increase in the next 20 to 50 years.
Four concluding points should be made. First, the nation's nuclear plants that 25 years ago struggled to operate at 75% of capacity have achieved truly remarkable levels of capacity performance. Indeed, today anything below 95% is considered worrying and question provoking. Consequently the degradation of output caused by cooling water problems is from a very high normal operating average.
Second, the country has excess generating capacity in just about all regions, with the notable exception of Texas. As a result of this excess capacity around the country, the loss of 2,600 megawatts of nuclear generation to heat problems is manageable, even in the middle of record heat that creates big peak demands.
Third, as temperatures continue to rise decade by decade, the cooling temperature water challenge for the nuclear fleet is going to deepen and worsen. The loss of nuclear output will likely rise in the coming years and could become a substantial issue for grid operations, in nuclear heavy areas like PJM, the home of Illinois and Pennsylvania, the nation's two biggest nuclear states.
Fourth, the loss of nuclear output almost certainly leads to increases in carbon dioxide pollution, as more coal and natural gas generation predominantly replaces lost nuclear generation. The loss of nuclear output is a negative for the environment, consumers, and grid reliability.
Finally, it is always true that when some form of generation does not operate something else takes its place. Saying no to nukes means saying yes to more coal and gas in this case.