6 things to know about the total solar eclipse 6 things to know about the total solar eclipse

6 things to know about the total solar eclipse

On April 8, a total solar eclipse will pass over Mexico, the U.S. and Canada. This unusual event is a balancing act for energy companies


Eclipse eye safety

Staring at the sun, even for a short time, is never a good idea. Doing so can cause permanent retina damage. The American Optometric Association says the only safe way to view an eclipse is by using special-purpose glasses or filters. Learn more.

For the first time since August 2017, a total solar eclipse will be visible in the U.S. This unusual event occurs when the moon passes between the sun and Earth, completely blocking the face of the sun. The sky will darken as it were dawn or dusk.

Here’s what to know about the April 8 eclipse and its potential impact on Duke Energy operations. Plus, lessons learned from the 2017 eclipse. 

A total eclipse occurs every 18 months or so

A total solar eclipse, when the moon completely obscures the sun for viewers on Earth, happens every 18 months, on average. The most recent total eclipse was visible in Antarctica in December 2021. The next one to happen after Monday’s will be in August 2025. That eclipse will be visible in the Arctic, Greenland, Iceland, Spain and Portugal.

Other types of eclipses – like annular, hybrid and partial eclipses – occur more often. An annual solar eclipse was viewable in parts of Oregon, California, Nevada, Utah, Arizona, Colorado, New Mexico and Texas in October 2023. This occurs when the moon is too far away from Earth to completely cover the sun.

A look at where the eclipse will shade Duke Energy's solar centers.
A look at where the eclipse will shade Duke Energy's solar sites.

Path of totality to span from Texas to Maine

The total solar eclipse will be visible for roughly 2 to 4 minutes along a narrow track stretching from Texas to Maine, though a partial eclipse will be visible throughout all 48 contiguous U.S. states. The path of totality will enter Texas at approximately 1:30 p.m. CDT and exit Maine at about 3:30 p.m. EDT.

The April 8 eclipse will pass over parts of Duke Energy’s service areas in Indiana and Ohio just after 3 p.m. EDT.

Fact #1 about the 2024 total solar eclipse.

Eclipse will impact solar power output

Electricity production will cease for just a couple of minutes at solar power sites in the path of totality. This includes utility-scale solar projects and customer-owned, behind-the-meter ones. In addition, solar assets will produce less energy leading up to and immediately after the total eclipse.

The regional transmission organizations that coordinate energy markets and operate transmission systems across Duke Energy’s Midwest service areas – Midwest Independent System Operator and PJM Interconnection – have been preparing for the April 8 eclipse for months. Each has identified generation sources that will be ready to cover the decreased solar power output, just like they do on cloudy days or during storms.

Duke Energy is preparing for reduced solar output across its Carolinas and Florida service areas, too. Even though these regions are well outside the path of totality, they’re set to experience a partial eclipse, which will reduce sun cover for a few minutes.

The company receives the output from roughly 5,100 megawatts (MW) of solar power in the Carolinas and more than 1,200 MW in Florida. These numbers don’t include the customer-owned, behind-the-meter solar assets, such as solar panels on the roofs of homes and businesses. These installations account for roughly 550 MW in the Carolinas and 815 MW in Florida.

Catch a glimpse of the 2017 eclipse

This 15-second time-lapse video was taken during the eclipse at Oconee Nuclear Station in Seneca, S.C. The World of Energy at Oconee hosted events including a watch party on its lawn. An exhibit of eclipse-inspired art is on view at the World of Energy.

Here’s what happened in 2017

In August 2017, the Great American Eclipse’s path of totality stretched across 14 states, from Oregon to the Carolinas. Most of the company’s solar sources in the Carolinas – about 2,500 MW at the time – experienced 85%-95% darkness for a few minutes.

Duke Energy initially estimated solar production would drop to about 200 MW over the course of 90 minutes on the day of the eclipse. It turned out to be a bit cloudy, so the panels weren’t operating at full capacity. In the end, solar output decreased by about 1,700 MW and the company used flexible fuel sources like natural gas plants to fill the void.

An interesting discovery: During the August 2017 eclipse, Duke Energy’s grid saw a reduction in energy use – rather than an increase in energy demand as streetlights switched on – of about 1,770 MW just before the eclipse. Experts think the drop in energy use was due to millions of people going outside to catch a glimpse of the stunning phenomenon.

Speaking of streetlights …

Duke Energy representatives have received requests from communities across the Midwest to deactivate streetlights, so they don’t automatically illuminate, as designed, as the sky darkens on April 8. These communities are aiming to reduce any lighting that could lead to less-than-optimal eclipse viewing experiences for their residents and visitors.

Chris Danforth, an Ohio-based manager of outdoor lighting programs for Duke Energy, says there are a number of reasons, most importantly public safety, that prevent Duke Energy from shutting off streetlight circuits.

Fact #2 about the 2024 total solar eclipse.

Danforth did say that Duke Energy has started deploying new outdoor LED control technologies that one day could allow the company to schedule temporarily shutoffs for emergencies, environmental purposes, or community events – like fireworks. He said it’s too early to say if the deployment will be far enough along by 2045 for this feature to be rolled out companywide.

What’s happening in 2045?

In just over 21 years – on Aug. 12, 2045 – a total eclipse will cross the U.S. from west to east. It’s path of totality will cross 10 states, including Florida, which is home to roughly 1.9 million Duke Energy electric utility customers.

Preparing for the 2045 eclipse could be difficult for the company. First off, the total eclipse will last about 6 minutes. It will also occur during the heat of a summer afternoon when the demand of air conditioning – and electricity – is typically very high.

There’s also no telling how much solar energy Duke Energy will have in service in Florida more than two decades from now. The company has 1,200 MW online today and plans to add more than 1,000 MW by 2027.

Here’s the good news: Duke Energy experts have 21 years to prepare for the 2045 eclipse.

In addition, the company has preliminary plans to add significant amounts of battery energy storage technologies to its system to work in conjunction with new renewable energy sources. This work supports Duke Energy’s goals to reduce carbon dioxide (CO2) emissions, a goal shared by other U.S. utilities and many of our customers.

So, total eclipse or no eclipse at all, the future remains bright for Duke Energy customers, employees and communities. 

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