When the day starts turning to night later this month, there’s no cause for alarm. At least the lights will go on.
Or that’s the assurance being given by the nation’s largest power grid operator, PJM Interconnection.
The total solar eclipse on August 21 will reduce generation from solar resources, whether they’re rooftop panels on a home or a solar farm providing power to the grid. PJM expects a temporary reduction of up to 2,500 megawatts.
Not to worry says the grid operator. It will use its sufficient reserves for replacement power.
The total eclipse will only be visible to portions of the United States, on a path from Oregon to South Carolina. A partial eclipse, in which about 73 percent of the sun will be blocked, will be visible from 1:22 p.m. to 4 p.m. in New Jersey.
“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 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 waves.’’
The exact amount of solar power affected by the eclipse will depend on how sunny or cloudy it is that afternoon. At its peak, the sun will look like a crescent, according to officials.
Certain states will experience a greater impact, including North Carolina, which will experience a complete solar eclipse, and New Jersey, which has more photovoltaic generation than most states served by PJM.
In New Jersey, 77,382 homes and businesses have installed solar panels as of June 30, according to the state Board of Public Utilities. The state has more than 2,000 megawatts of installed capacity.
Within PJM, about 500 megawatts of solar generation are connected to the grid. Another 2,000 megawatts are generated by rooftop solar panels that serve individual customers. When those panels are not running, the homes draw power from the grid, increasing demand on the system.
Although growing in the region, solar generation makes up less than 1 percent of PJM’s 185,000 megawatts of generation capacity. Generally, 1 megawatt can power up to 1,000 homes.