On April 8, millions of bespectacled onlookers will hold their breath for the second time in seven years. As the celestial odds align, the Earth and moon will be in perfect position to blot out the sun over the US, along with solar power making up an increasing portion of our energy mix. With eclipses expected decades ahead, local utilities have had time to prepare for the big day. From tiny Vermont to big Texas, how the blackout will affect the energy grid paints a picture of energy progress, but also how we still depend on fossil fuels to stay resilient.
During the last total solar eclipse in 2017, an approx 10 million pounds of extra carbon emissions were released into the U.S. atmosphere as fossil fuel-based power stepped in to replace the loss in solar output, according to Vahe Peroomian, a professor of physics and astronomy at the University of Southern California. This is the annual equivalent of 1,000 petrol cars. Since then, “our dependence on solar energy has increased by approx a factor of three,” Peroomian said, meaning the amount of energy to make up will be greater than any previous eclipse.
Each of the 15 states along the 115-mile path of totality, in which the sun will be completely eclipsed for a brief period, has a different mix of power sources feeding their grid. From the moment the moon’s shadow begins to creep over the sun, until it gives up its grip, their systems will have to turn it on.
Even a small shadow on the sun translates directly to lost energy. Batteries and other renewable energies, such as wind, are expected to pick up some of the slack. Even a leading clean-energy state like California, which will experience only a partial blackout, may need to tap into its fossil fuel resources to keep up with demand, Peroomian said. “The impact will be nationwide.”
The blackout is a challenge for states to prepare for, highlighting how a renewables-reliant grid can handle sudden weather changes, equipment outages and other disruptions. According to the US Energy Information Administration, or OIA, utilities also expect increased demand from homes and businesses that rely on small-scale solar powerwhich may need to draw power from the grid instead.
Texas is the largest state to experience totality and has some unique factors that make it the ultimate testing ground for solar reliance. While other states use a larger local utility system, Texas is an energy island and its grid primarily uses energy produced in the state. It also recently became a nationwide leader in solar energy, with nearly a 3,700 percent increase in the past decade. In most of the state, the blackout will momentarily wipe out about ninety percent of that power.
“It’s perfectly timed to have maximum impact,” said Joshua Rhodes, an energy researcher at the University of Texas at Austin, who says the eclipse will cross the state at “solar noon,” the time when the sun is at its highest in the air and produces the most energy. But after 14 years working with the state’s utility provider, ERCOT, Rhodes is confident the grid is ready for the occasion. “I mean really we do it every day,” he said. “A cloudy day could create the same kind of gap that we will see on Monday.
After a 2021 winter storm that caused days of blackouts, Texas has invested in grid resiliency, with an emphasis on renewable energy and giant power-storage batteries, which can provide energy when sources go offline. But the state still relies on fossil fuels for approx 60 percent of his energy. In 2023, when a partial solar eclipse passed, the loss of energy caused the amount of natural gas used to almost double instantly.
Still, while the eclipse offers a glimpse into our continued reliance on fossil fuels to meet demand, the recent emergence of energy storage signals a shift toward cleaner resilience. Today, according to the EIA, the US has 15.4 gigawatts of battery storage, captures solar and wind energy to release when needed. During the 2017 blackout, the US had only 0.6 gigawatts of these reserves. Even with the lost sunlight, the agency said it expects solar power to be the third-largest energy source in the U.S. on eclipse day.
April 8 is also likely to see increased emissions from another source: the crowds that will flood into cities along the path of totality, in numbers similar to 50 Superbowls, with most arriving in gas-guzzling planes and cars. In largely rural Vermont, some fear miles of stationary, idling trafficwhich overwhelms the state’s back roads and highways.
“Our biggest consideration is if somebody has an outage or something, you know, how do we actually get to them?” said Andrea Cohen, manager of member relations at Vermont Electric Cooperative, which serves 78 towns in the state’s north. But when it comes to obtaining energy, Cohen says the utility is “well prepared” for the blackout, just as they would be on a bad weather day.
