April 8 Eclipse Will Drop U. S. Solar Power by 39.9 GWh

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Written by Paul Wiseman for Industrial Info Resources (Sugar Land, Texas)--Some media outlets along the path of the April 8 total eclipse are warning residents to load up on gasoline and basic groceries in anticipation of an influx of "umbraphiles," or "shadow lovers," seeking to experience the event in person. Power grids are preparing for a temporary drop in solar power input during the middle of the day when otherwise, barring dust or clouds, solar panels would be most productive.

The path will span 13 states from southwest Texas (near San Antonio) to Maine, with its duration of totality averaging 3.5-4 minutes in any one location. The eclipse's long U. S. trek, combined with the nation's increase in dependence on solar power, will cause the event to affect the power grid more than any other, including the eclipse in 2017. In the time of the earlier eclipse, the U. S. generated only 1.3% of its grid power by solar energy, according to the U.S. Energy Information Administration (EIA). Today, the agency lists the solar share at closer to 6%.

Even so, the event is not expected to make much of a dent in the daily life of a power grid, and no utility is expected to ask for usage reductions.

That's because it won't be a surprise, according to experts at Solcast, a solar modeling and forecasting company. Unlike a storm or an equipment failure, solar eclipses are predictable literally centuries in advance. Grid operators have been in the planning process for months, assuring plenty of backup in natural gas, coal, storage and anything else that would make up the difference.

Solcast expects the event to cost operators up to 16% of solar irradiance during its trek. In addition to the 3.5-to-4-minute totality, the company predicts the eclipse will have at least some diminishing effect on irradiance for up to 90 minutes in some areas in the middle of its path.

Adding up numbers across all U. S. grids, the firm estimates maximum losses to be as high as 39.9 gigawatt hours (GWh). Just under half of that, 16.2 GWh, will be from household rooftop panels. This group, consisting of about 4.2 million households, will be the main ones to notice any issue with electricity supply. Solcast notes that, "As this happens, grid operators will face a sharp decline in solar supply and a surge in demand as these 4.2 million households draw power from the grid."

To compensate, grid operators have plans to switch to natural gas to ensure stability, "as was done during the previous eclipse in 2023 in California and Texas." A case in point, the Electric Reliability Council of Texas (ERCOT) expects solar power to drop to about 10% of its potential assuming clear skies, but plan to pick up the slack with other energy input.

Solcast's statement notes that its data is limited to large ISO grids and is based on modelled estimated capacity. And all predictions of reduction are compared to a maximum solar day, without clouds or significant dust.

Gassing Up
Industrial Info's Hillary Stevenson said gasoline prices could tick up just a bit. "An estimated 3.7 million people are expected to travel to view the eclipse. That, combined with spring break driving, is expected to lift gasoline demand for week ending April 12. The gasoline demand impact may be lower than in the 2017 event since the 2024 eclipse path covers more densely populated areas. Nearly 20 million people traveled to another city for the 2017 eclipse, when fatal car accidents also saw a spike."

Demand may rise a bit, but there should be plenty to go around, according to two national organizations that track such things. AAA's Spokesperson/Media Relations Manager Aixa Diaz said, "This year's eclipse falls during spring break season -- a time of year we normally see higher prices. In addition, because gas stations set their own prices, there could be stations along the path of totality that adjust prices based on higher demand. But barring any breaking news in the oil market, we don't anticipate a sharp spike in prices because of the eclipse."

GasBuddy's Head of Petroleum Analysis, Patrick De Haan, said: "We have not made any projections, other than that we do not expect any major impact to prices. There may be isolated challenges in rural areas as stations can't accurately predict consumer demand in some remote areas," he said in an email interview.

Here again is an area where the eclipse is not going to be a surprise, and eclipse-area suppliers likely have had ample time to fill distribution tanks and schedule extra jobber trips if necessary. Perhaps the bigger danger is that, as with toilet paper in 2020, a spree of preemptory fill-ups creates an artificial shortage ahead of the event.

Industrial Info Resources (IIR) is the leading provider of industrial market intelligence. Since 1983, IIR has provided comprehensive research, news and analysis on the industrial process, manufacturing and energy related industries. IIR's Global Market Intelligence (GMI) platform helps companies identify and pursue trends across multiple markets with access to real, qualified and validated plant and project opportunities. Across the world, IIR is tracking more than 200,000 current and future projects worth $17.8 trillion (USD).