Transmission towers near the CenterPoint Energy facility on December 22 in Houston.

Photo: Brandon Bell/Getty Images

As temperatures plunged this weekend, Americans in much of the country were told to turn down their thermostats and avoid using large appliances to prevent rolling blackouts. The cascading grid stress came at an awful time but was all too predictable to anyone paying attention.

The interconnected U.S. grid is supposed to be a source of resilience, but the government’s force-fed green energy transition is creating systemic vulnerabilities that politicians don’t want to acknowledge. Utilities and grid operators weren’t prepared for the surge in demand for natural gas and electricity to heat homes, which occurred as gas supply shortages and icy temperatures forced many power plants off-line.

The PJM Interconnection, which provides electricity to 65 million people across 13 eastern states, usually has surplus power that it exports to neighboring grids experiencing shortages, but this time it was caught short. Gas plants in the region couldn’t get enough fuel, which for public-health reasons is prioritized for heating.

Coal and nuclear plants can’t ramp up like gas-fired plants to meet surges in demand, so PJM ordered some businesses to curtail power usage and urged households to do the same through Christmas morning. Rolling blackouts were narrowly averted as some generators switched to burning oil. Americans in the southeast weren’t so lucky.

The Tennessee Valley Authority and Duke Energy in the Carolinas ordered rolling blackouts as demand for heating surged. Two-thirds of the South relies on electricity for heating. While gas-power generation doubled in the TVA and tripled in the Carolinas, this wasn’t enough to keep the lights on and homes heated.

The climate lobby wants to force all homes and buildings to shift to electric heating even though it is less efficient than gas furnaces in frigid weather. When temperatures fall below freezing, heat pumps consume more and more power. “With a generation fleet that is more nat gas heavy than ever before, we are using twice as much gas to heat homes through electricity as we do with gas furnaces,” former Federal Energy Regulatory Commission Chairman Pat Wood told Bloomberg.

Population growth in the Sun Belt has increased the strain on the grid—even as large numbers of coal and nuclear plants that provide baseload power have shut down owing to competition from heavily subsidized renewables and cheap natural gas. The Texas grid has become especially dependent on wind and gas.

Natural gas is usually a reliable power source that can ramp up when demand increases or wind power flags. But in very cold temperatures pipes can freeze and gas is diverted for heating. On Friday morning, wind power and temperatures in Texas both plunged. As electric demand hit a winter record, gas power generation doubled.

Worries about a gas shortage spurred the U.S. Department of Energy on Saturday to declare a grid emergency in Texas and ease emissions standards to allow gas plants to burn oil if necessary. Don’t tell hapless Energy Secretary Jennifer Granholm,

but oil comes to the grid’s rescue during extreme weather—not lithium-ion batteries, which can’t discharge power for more than a few hours.

New England leaned on oil to generate 40% of its power this weekend even as its grid operator pleaded with customers to conserve power. New York’s embargo on gas pipelines limits supply to New England, which depends on gas for heating and increasingly electricity as coal and nuclear plants have closed. But the region can’t import enough liquefied natural gas in a pinch.

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While there wasn’t a single cause for the power shortages, government policies to boost renewables snowballed and created problems that cascaded through the grid. The North American Electric Reliability Corporation warned about these system-wide grid vulnerabilities in a report last month, as did a study commissioned by the Trump Department of Energy in 2017.

The climate lobby dismisses such warnings and blamed the weekend’s power outages on the “bomb cyclone” supposedly caused by climate change. But storms happened before climate change became the default political explanation for everything. The Christmas emergency was a near-run disaster, and unless the political class wakes up, next time may be worse.