Why is America getting hit with blackouts this winter?

The United States electricity system largely runs on natural gas, and that system was put under severe stress across the country as extreme cold and storms affected the nation’s grid this week.

Cold weather stresses many power systems as the demand for heating homes and other indoor spaces — whether gas or electric — surges.

Much of the country is dependent on natural gas

In New England, which has meager natural gas infrastructure and relies on imported liquefied gas to get through the winter, gas consumption soared in the last week alongside the use of oil. While oil plays only a minor role in electricity generation in the United States, power plants in New England will use oil when demand gets especially high. This is because natural gas supplies cannot both heat homes and keep the lights on when demand for both power and heat is high.

“Even if you get 30 or 40 percent from oil, only 20 percent from nuclear, almost no coal, less than 10 percent renewables usually, you’re still getting a lot of natural gas.” And while overall natural gas use in New England was high this week, according to Energy Information Administration data, natural gas consumption in New England was just under twice the average of the past four years. However, prices were almost six times what they were last December. In other words, both gas prices and usage are up from last year.

Coal is a backup option — but even coal plants are disappearing

Oil wasn’t the only backup fuel localities used as temperatures dropped.

Coal plants throughout the country are rapidly being retired. Coal generation has almost been cut in half in the past decade, while natural gas electricity generation has increased by more than 50 percent. And coal power is not perfectly reliable in inclement weather either. The TVA told the Chattanooga Free Press that winds damaged one of its coal plants and several gas facilities.

Some have pointed to generation and transmission struggles as evidence of the brittleness of America’s natural gas infrastructure, which is responsible for more electricity generation than any other single source (38.4 percent). For the industry, the past week has shown just how much the U.S. depends on natural gas.