San Diego Gas & Electric is readying backup power sources when the “Great American Eclipse” on Monday reduces solar power output across the western United States.

The sun is expected to be obscured by nearly 60 percent locally, resulting in a loss of 500 megawatts of solar generation — about 14 percent of the electricity San Diego customers consume on a typical warm summer day.

During the eclipse, which begins at 9:07 a.m. and ends at 11:46 p.m., SDG&E will rely on natural gas-powered generators and energy storage to make up for the power lost from rooftop solar.

“Managing and operating a power grid is a 24/7 job and while we plan ahead, there are often quick decisions that need to be made to maintain a balance between the exact amount of electricity at the exact time to consistently meet the energy needs of the region,” said Caroline Winn, the utility’s chief operating officer. “Predicting how the obstructed sun will interfere with solar production has added another level of complexity, but we want to reassure our customers that we have secured enough resources to meet their energy needs — even with significantly less solar generation on hand.”

While there is no call for conservation at this time, SDG&E is reminding customers to consider small changes to save energy, such as not charging an electric vehicle or running a washing machine during the eclipse.