Solar eclipse draws attention to solar’s increasing role in energy landscape

By Cal Kielhold on August 5, 2017

The earliest recorded solar eclipse, when the moon passes in front of the sun creating a brief period of daytime darkness, occurred during the 22nd Century BCE. Legends state that two Chinese court astronomers were executed for their failures to predict and prepare for the eclipse, as eclipses were believed to be omens foretelling the health of kings. Since then, eclipses repeatedly have been associated with kings and their nations, with legends and superstitions linking eclipses to the deaths of King Henry I and Queen Anne Neville.

While it’s unlikely the upcoming eclipse on August 21 will result in the overturning of any kingdoms, the preparations some states are making underlines solar ever-increasing role in energy generation. The last time a total solar eclipse was viewable on the continental United States was in February of 1979, a time when the state of the American solar industry was very different than today. Since 1979 more than 44,000 MW of solar has been deployed. Solar is an integral part of the electric grid and home and businesses generation.

For example, more than 10% of California’s generation comes from solar, representing 50% of solar production nationwide. This demonstrates how solar has now grown to represent an ever -increasing part of the energy landscape. California Independent System Operator (CAISO) estimates a loss of over 6,000 MW of generating power during the eclipse. Experts estimate 70 MW/minute will be lost as the shadow approaches, and then solar production is expected to ramp up at a rate of 90 MW/minute afterward. Even in this case, it shows how advanced planning can address any challenges that solar can be managed.

As more homes and businesses employ on site ‘distributed generation’ with solar. The eclipse may temporarily affect production at these sites. But, as the power grid utilizes a variety of power sources like traditional wind, and hydro power – there are no projected disruptions.

Fortunately, a similar eclipse crossed Europe in March of 2015. This will give California utilities insight into how to prepare for the drop in production. Electricity reserved from gas-fired and hydro-electric plants should be enough to offset the loss, particularly given California’s glut of snowfall this year. In the future, storage resources like batteries could also play a role. Similar plans to those in California are in place for North Carolina, where the solar industry is smaller but still a presence. This work demonstrates the integration of solar and other renewable sources is a matter of planning. The North American Electric Reliability Corporation (NERC), a nonprofit corporation formed to “ensure the reliability of the North American bulk power system,” expects no major disruption to the grid’s reliability but does recommend utilities prepare and study the eclipse for the future.