|Fig. 1: Temperature map of the atmosphere at a height of approximately 1 km (pressure = 0.86 atmospheres) reported from the NASA Atmospheric Infrared Sounder (AIRS) Satellite on 6 Jan 14. The temperatures range from -28°C (violet) to 17°C (deep red). (Courtesy of NASA)|
The polar vortex is a high altitude, low-pressure weather system that generally hovers in the Northern Hemisphere over Canada's Baffin Island or northeast Siberia.  It is strongest in the winter season due to the increased temperature contrast between Polar Regions and mid-latitudes like the United States.  From January 2nd through January 7th, 2014, a powerful high-pressure system from the Eastern Pacific stretched into the North pole, pushing a large piece of the vortex was forced well to the south of its usual zone of movement.  The result was cold arctic air blowing into the central, southern, and eastern U.S. in large quantities.
The result was record low temperatures and record heating demand in parts of the United States. PJM Interconnection - the largest U.S. grid operator, reached a new record peak load of 141,500 megawatts. Interestingly, this load came when almost 1 in 5 PJM generators were down due to the weather.  Further, PJM said there was a danger that extraordinary demand for natural gas to heat homes could force the curtailment of gas supplies to some power plants.  As such, one of the main reasons generators went down during the vortex were due to natural gas pipeline constraints; as demand for natural gas went up, so did its price.  For example, in New York, this raised gas prices from $13 per million Btu over the weekend to nearly $50 million on Monday, January 6th.  Other sources of failure include frozen coal stacks and diesel generators that are essentially unable to function at such low temperatures.  In New England, natural gas electricity generation stumbled enough that ISO New England had to bring up dirtier coal and oil plants to cover the difference, and the state needed a 75% increase in supplies of gas coming out of Canada to meet the demand. [2,3]
During this time in which other forms of electricity generation were failing, nuclear power was extremely steady. As temperatures fell to their lowest, 97 of the 100 nuclear reactors in the US were operating, while only 3 were generating below 90% capacity.  On average, the whole fleet operated at 95% capacity, according to NEI.  Remarkably, these plants were indeed stronger in the cold weather, as the plants' efficiency increases as the difference between outside air and supply air increases.  This output proved crucial to the grid's ability to weather the polar vortex. In New England, nuclear energy became the primary provider of electricity, accounting for 29% while natural gas only supplied 27% of the region's demand. Oil and coal came in at 15% and 14% respectively.  And these types of numbers aren't indicative of the year round usage rate. In 2013 through November, natural gas's share of electricity demand was 30%, compared to 25% from coal, 19% from crude oil, and 10% from nuclear energy. 
These statistics point to an over-reliance on coal for electricity, as well as natural gas. While some would argue that the best solution is to increase fracking, thereby increasing the amount of natural gas available in a time of high demand, but it cannot be ignored that this occurrence of the polar vortex - the first of its kind in 20 years - has shown nuclear energy to be a hugely dependable source of electricity. Without nuclear energy, demand would not have been met, leading to widespread blackouts and the consequent danger to the public at such low temperatures.  Not only does this prove that nuclear can be relied on today, but that it is worth developing newer and better reactors, and committing to research heavily on ways to improve the already reliable source.
© Colin Epperson. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 D. W. Waugh and W. J. Russell, "Climatology of Arctic and Antarctic Polar Vortices Using Elliptical Diagnostics," J. Atmos. Sci. 56, 1594 (1999).
 J. Conca, "Polar Vortex - Nuclear Saves The Day," Forbes, 12 Jan 14.
 P. Hill, "Frigid Weather Strains Fuel Supplies at U.S. Utilities," Washington Times, 7 Jan 14.
 Chediak, Mark, and Harry R. Weber. "Polar Vortex Emboldens Industry to Push Old Coal Plants." Bloomberg.com. Bloomberg, 10 Mar. 2014. Web. 18 Mar. 2014.
 "Monthly Energy Review," U.S. Energy Information Administration, DOE/EIA-0035(2014/02), Feburary 2013, p. 5.