Numbers Are In: Fossil Fuels Kept Furnaces Running During Polar Vortex

Michigan experienced an extreme midwinter cold snap earlier this year, and on several days, the high temperature at Detroit Metro airport was zero degrees or colder.

During a roughly three-day period ending Feb. 2, air temperatures as low as 23 degrees below zero were recorded in the Lower Peninsula, according to the National Weather Service. Temperatures in the Upper Peninsula dropped to 26 degrees below zero. Other states in the Midwest and Great Lakes region also faced very low temperatures.

During this period of extreme cold, the regional electric grid relied on power generated by coal, natural gas and nuclear plants to provide up to 97 percent of the electricity used, with little coming from solar arrays or wind turbines.

On Friday, Feb. 1, nearly half the electricity produced in the MISO grid (47 percent) came from coal. (MISO operates the electric grid that serves 15 states, including Michigan, and one Canadian province.) According to MISO, coal accounted for 63 percent of the production in the Central States, a subset of its territory that includes Michigan, Wisconsin, Illinois and Indiana.

In the depths of the polar vortex, electricity demand was up markedly. But as temperatures began to return to normal on Feb. 1, the Central State’s average electricity production from all sources decreased by 15 percent (45,264 megawatts per hour to 38,606 MW per hour).

from Jan. 30 to Feb. 1, the Central State’s average electricity production from all sources decreased by 15 percent (45,264 megawatts per hour to 38,606 MW per hour).

Production from coal was down 5 percent (25,513 MW per hour to 24,198 MW per hour).

Production from natural gas was down 28 percent (10,684 MW per hour to 7,756 MW per hour).

Production from wind was down 79 percent (2,461 MW per hour to 506 MW per hour).

Electricity generation from sources like wind turbines goes hand-in-hand with having abundant electricity generated by natural gas, which provides a necessary backup when the wind doesn’t blow. As the polar vortex waned, the amount of electricity generated by both natural gas and renewables dramatically decreased in the Central States region. Natural gas is important not only for producing electricity but for fueling home furnaces. In many states, including Michigan, a majority of homes are heated by natural gas.

The overall drop in wind production during the polar vortex could be linked to poor wind conditions, or to the fact that in some cases, the extreme cold made it dangerous to operate wind turbines. In Michigan, natural gas supplies were constricted after a fire at a natural gas facility owned by electricity and gas utility Consumers Energy.

Note: Although most Michigan homes are heated with furnaces that burn natural gas, those furnaces stop working without electrictity to power the blower fan (and on high efficiency models, to power the combustion impeller fan too).

Editor's note: The headline was changed in this story and the article was altered to provide more context to the drop in electricity production.