The total solar eclipse is a test case for renewable energy in emergencies

A dark day is coming but the lights will stay on.
A dark day is coming but the lights will stay on.
Image: Reuters/Darrin Zammit
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Like many, energy expert Phil Mihlmester is looking forward to the total solar eclipse on Aug. 21. Although he’s not in the path of totality, Mihlmester plans to step outside under a briefly darkened Maryland sky, don special glasses, look up, and marvel, assuming the weather allows it.

Unlike most, however, the executive vice president for global energy at ICF, an international energy industry consulting firm, will also be thinking about power grids worldwide. ”The total solar eclipse is a test case for renewable energy generally and weather events,” Mihlmester says. ”As solar energy reliance becomes increasingly common, we’ll want to know how to ramp up fast and switch to an alternative power supply from solar quickly during an event.”

The eclipse, then, is a kind of planned emergency, an expected oddity that can help grid managers anticipate what a real emergency would be like.

The difficulty will be in switching from solar energy to gas-powered turbines, and ramping up supply very quickly. Mihlmester says the lessons learned will also inform decisions about how to include other renewable sources, like wind, in future power portfolios. “We’ll know what to expect in terms of the effect of ramp-up times for turbines, and we’ll understand better the right balance for a mixed portfolio of energy sources,” he explains.

The last time there was a total solar eclipse in the US was 1979. Renewable energy wasn’t exactly common then. Now it’s much more so. The Solar Energy Industries Association reports that solar energy generation has grown by an average of 68% annually in the past decade in the US, and is now a sizable element of power grid portfolios in many states—most notably California, which relies on solar for 10% of its power and generates half of the nation’s total solar supply. The cost of installing solar panels has dropped by more than 70% since 2010, says the association.

Industry insiders have been planning for the eclipse for over a year. Steven Greenlee, spokesperson for the power grid California Independent System Operator, told Vox, “Our solar plants are going to lose over half of their ability to generate electricity during the two to two and a half hours that the eclipse will be impacting our area.”

Still, Mihlmester believes all will go well and that there’s nothing to fear next week. “Nobody needs to worry. Electricity coming from solar panels may be rendered inoperative. But lights will stay on.”