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On August 21, 2017, the United States will experience its first coast-to-coast solar eclipse in 99 years. When such an event last occurred in 1918, the energy landscape in America was of course dramatically different than it is today.

Given the rapid growth of the renewables industry in the U.S., specifically solar power, many wonder how the eclipse will impact the reliability of the energy grid. According to the U.S. Energy Information Administration (EIA), approximately 1,900 utility-scale solar plants will undergo some level of impact due to the event. While most solar facilities will notice some degree of impact, relatively little solar capacity lies in the direct path of the total eclipse. The North American Electric Reliability Corporation (NERC) has advised that it “does not anticipate the eclipse to create reliability issues for the bulk power system.”

In fact, according to the EIA, only 17 utility-scale solar facilities lie in the “path of totality” and most of those are in eastern Oregon; it is worth noting, however, that a far greater number will be obscured at least 70%.

solar eclipse

Source: U.S. Energy Information Administration

Regional balancing authorities work to ensure that power system demand and supply are accurately balanced across the U.S. electric system. Since these solar facilities use sunlight as fuel, the capacity of these facilities will be reduced accordingly. During the eclipse, these balancing authorities will replace the capacity lost from solar generation with energy from other sources. In fact, some utilities which have higher concentrations of utility scale solar have proactively scheduled solar curtailments to enable a smooth transition among the varying technologies of their energy portfolios. This event will demonstrate the resiliency of the U.S. energy grid and how the differing generation technologies complement each other to manage the varying demands of the overall energy infrastructure system.

As one of the nation’s largest independent solar power producers, Silicon Ranch owns and operates more than 100 solar facilities in 14 states across the country. Three of our facilities are in Nashville, Tennessee, not far from our corporate headquarters. Nashville is the largest U.S. city in the path of the eclipse, and these three facilities will see complete system outages during the total eclipse. The impact from this event will directly correlate to the loss of solar irradiance (sunlight) on other facilities that lie outside the path of totality. Through Silicon Ranch’s supervisory control and data acquisition (SCADA) system, our Operations & Maintenance engineers will be monitoring ongoing real-time meteorological and plant production data for our entire portfolio coast-to-coast.

The entire event will last approximately three hours as it works across the U.S., although the total eclipse will only last a couple of minutes at each location. The eclipse will affect most of our plants like a heavy storm rolling through, albeit much more briefly. Sites within the most direct path will see a momentary loss in production as the sun is being obscured, but will ramp back up as soon as the event completes its course.

Skywatchers from across the globe will be in Music City to witness this once-in-a-lifetime celestial event. Members of the Silicon Ranch team plan to volunteer at a local high school during the event to support STEM educational activities, and we look forward to the opportunity to share our solar expertise with the next generation.

For a wide range of educational materials related to the eclipse, NASA has created a webpage devoted entirely to the event: https://eclipse2017.nasa.gov/.