How Nuclear Energy Keeps the Grid Up in Extreme Weather

Matt Wald

The following is a guest post from Matt Wald, senior director of policy analysis and strategic planning at NEI. Follow Matt on Twitter at @MattLWald.

Over the past ten years, two of the power grid’s worst ten days were during the polar vortex of January 2014, and for 2014 alone, four of the top ten were caused by the vortex, according to a new report by the group that enforces reliability standards on the high-voltage grid.

Weather-related challenges to the grid can be divided into two categories: the ones that disrupt load and the ones that disrupt generation. Thunderstorms, snowstorms, derechos and similar events that tear down local power lines are in the first category, and extreme temperatures are in the second. The distinction is important because if the power line in your neighborhood is taken out by a snow-covered tree, then it doesn't matter if the power plant is still running, and the system can get by on many fewer power plants as load disappears. But in a polar vortex, transmission and distribution is intact and it is the performance of the generators that is crucial.

With the grid up and demand rising, nuclear energy did its job in 2014.

The report, “The State of Reliability 2015,” pointed out that in the vortex, temperatures dropped 20 to 30 degrees below normal, and 49 cities set new low temperature records. “Key factors during the event included fuel deliverability issues, natural gas pipeline outages, gas service interruptions, frozen electricity and gas equipment, and other extreme cold weather operating challenges,’’ the report said.

And the wholesale price of electricity shot through the roof – which this report didn't mention, because the group that prepared it, the North American Electric Reliability Corporation, is concerned with the engineering details of keeping the lights on, not the financial details of what happens when the gas transmission system can’t feed the power plants, factories and home heating systems.

The system mostly scraped through the challenge, largely because of the generators that ran without difficulty, nuclear reactors, which had their fuel already on site, and thus did not suffer from gas pipeline constraints or frozen coal piles, or the inability of barges to bring fuel over ice-choked rivers. Their performance was an example, mostly unappreciated, of the strength that the grid draws from its diversity.