Back in March I talked about California’s “duck curve”. (see here) One of the interesting side-effects (or challenges) of this situation will come to the forefront on August 21st, when a solar eclipse is scheduled to hit the country. The large amount of solar capacity in place in California will all be turned off simultaneously, which means that the California ISO (CAISO) will have to find a way to quickly replace it. A briefing by CAISO reviewing the situation can be found here. CAISO estimates that supply will drop off by 70MW/min at the beginning of the eclipse, and it will return at about 90MW/min as the eclipse ends. This compares to a typical ramp rate of about 29MW/min.
A white paper from the North American Electric Reliability Corporation (NERC) is available here. NERC’s paper covers the issue on more a national scale than the CAISO briefing, but concludes that California and then North Carolina are the places that will likely need to do the most preparation for the event.
Source: NERC white paper
A similar event took place in Europe in 2015, and it was dealt with successfully. The post-event briefing for that eclipse can be found here.
This will likely end up being a non-event, as there is lots of time to prepare. But, it does highlight the challenges that can come from renewables, and if there are complications that day it could impact renewable growth going forward. Stay tuned.