PJM prepared for effects of Monday’s eclipse
Grid operator says event will eliminate solar for several hours but arrangements have been made
VALLEY FORGE » Some are traveling to see it in all of its glory.
Others are planning to stay inside until it’s over.
But as the first coast-to coast total solar eclipse in 38 years nears, workers on the nation’s power grids have a different concern: keeping the lights on.
PJM Interconnection, the operator of North America’s largest power grid, including the one in this region, says Monday’s eclipse is an issue it has had to prepare for since it will affect the amount of solar energy produced that day.
But, the company said, it expects to handle the hours-long event without any interruption in electric service.
PJM’s operating area includes 13 states and the District of Columbia and 65 million people.
“Certainly, this is an unusual solar event, but as far as potential impacts to the grid, PJM and its members are prepared,” said PJM President and CEO Andrew L. Ott. “While this is an anticipated event, we routinely plan and prepare for unpredictable events or things that can’t be forecast far in advance, such as severe storms and heat waves,” he noted.
When the moon blocks the sun on Monday, solar power generators will lose their fuel source in varying degrees from 1:30 to 3:40 p.m., the company said. PJM expects a temporary reduction in solar power of up to 2,500 megawatts. It will use its sufficient reserves for replacement generation.
The exact amount of solar power affected by the eclipse will depend on how sunny or cloudy it is that afternoon, PJM said.
Europe experienced a total eclipse in 2015 with no impact on electric reliability because of coordinated planning for the ramping up and down of electricity on the grid.
The last total solar eclipse to occur in the continental United States was in 1979, before the rise of solar power. It was viewable only from the Pacific Northwest.
On Monday, certain states will experience a greater impact, including North Carolina, which will experience a complete solar eclipse, and New Jersey, which has more photovoltaic solar generation than most other the states served by PJM.
Mike Bryson, vice president of operations at PJM, said the effect on electric supplies would be similar to when a thunder storm moves through an area – but across a much broader swath.
In southeastern Pennsylvania, the eclipse won’t be total, but rather 75to-80 percent, astronomers say.
“It’s going to be more like a dark, cloudy day” for electric generators in PJM’s grid, Bryson said. “We’re in good shape, we’ll have some in reserves.”
One reason PJM is confident it can handle the unusual event is the fact that solar generation comprises less than 1 percent of its 185,000 MW of generation capacity.
About 500 MW of solar generation is connected to the grid. Another 2,000 MW is generated by rooftop solar panels that serve individual consumers. For context, 1 MW can power up to 1,000 homes.
A reduction in power from the rooftop panels will result in an increase in electric demand on the grid from those electric users, PJM noted.
Bryson said PJM will be watching closely Monday to see how its system reacts because it expects to have more solar-generated electricity in its grid when the next total solar eclipse occurs in its coverage area, in 2024.
August’s planetary event will be the first total eclipse since the year 1257 to begin and end exclusively over the territory that now makes up the United States, according to NASA.
Founded in 1927, PJM covers all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia.