Polar Vortex - Nuclear (and Wind) Save The Day

[FBaggins]

It’s all about diversity. Whether in biology, in culture, in training, or in technology, when conditions change a system survives if there is sufficient diversity to adapt. Otherwise it dies. And things always change. This is no less true for electricity production. Having a diverse energy mix is key to a society surviving changes in demographics, government, geologic processes and natural disasters, supply disruption during war, and extreme weather changes. This concept was in full display last week during our run-in with a certain polar vortex. In which nuclear and wind stepped up to the plate to relieve natural gas and coal when they failed to deliver on demand.

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The electrical grid was not immune to the effects of this massive cold snap (IEEE). All generation systems suffered outages as vortex effects hammered half the U.S., but most of them involved fossil fuel systems. Coal stacks were frozen or diesel generators simply couldn’t function in such low temperatures. Gas choked up – its pipelines couldn’t keep up with demand – and prices skyrocketed.


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But nuclear did quite well throughout the vortex period. The entire fleet operated at 95% capacity, a ridiculously high value (NEI). And not just that, but most individual nuclear plants actually produced more energy because of the cold weather. The energy output of any thermal (steam) power plant depends on the temperature difference between the steam and the outside/condenser temperature (the Carnot cycle). So these really low temperatures actually increased the efficiency of the nuclear plants a bit. A similar, but lesser, effect occurred for wind energy. Usually extreme cold is not accompanied by sufficient wind speeds to make wind useful in generation, but the vortex produced some very nice wind speeds, especially along its periphery. Together with the huge demand on gas that exceeded its supply and spiked gas prices, utilities that had significant wind capacity, like in Nebraska and Texas, were able to make up a lot of the difference lost from gas (American Wind Energy Association).

http://www.forbes.com/sites/jamesconca/2014/01/12/polar-vortex-nuclear-saves-the-day/

[PamW]

1. Nuclear and the Chicago Climate

The climate in Chicago and northern Illinois is one of the primary reasons that the region is powered by nuclear power to the degree it is.

It gets cold in Chicago, and Chicago is right on Lake Michigan. The result of cold temperatures and higher humidity in the air due to the vicinity of Lake Michigan resulted in frozen piles of coal in decades past. Having small mountains of coal fuel at their power plants but being unable to use it due to the frozen condition of the piles led to shortages of electric power back in the days when Chicago and northern Illinois, like the rest of the country, was primarily fueled by coal.

Nuclear power doesn't have that problem. A reactor is loaded at regular intervals with new fuel ( typically replacing about 1/3 of the core at any given outage ) and the reactor then runs for a year to 18 months on the fuel already on board. There's no need to bring in fuel that is exposed to the elements.

Any electric generation technology wherein the equipment is exposed to the elements has to be able to deal with the effects of those elements.

It is true that lower ambient temperatures increases the efficiency of the Rankine steam cycle which is used in nuclear and coal fired plants as well. That is a consequence of the 2nd Law of Thermodynamics.

However, there are a number of denizens of DU that don't believe in the 2nd Law of Thermodynamics, and don't understand its implications. I wonder how they explain the increased efficiency of Rankine steam cycles when ambient temperature drops?

The good thing about science is that it is true, whether or not you believe in it.
--Neil deGrasse Tyson

PamW