Next month’s solar eclipse could threaten solar farms and rooftop panels across the United States, in the process wiping out enough power to supply seven million homes. A total solar eclipse has not occurred in the U.S. since 1979. On August 21, however, the moon will totally obscure the sun and cast a 70-mile-wide shadow from Oregon to South Carolina:
Source: NASA Scientific Visualization Studio
According to Bloomberg, the shadow from the eclipse could shut down more than 9,000 megawatts of solar power. The eclipse highlights a risk associated with solar power and the increasing transition toward renewable energy. Solar installations have increased by nine-fold in the country since 2012. The increase in solar and wind sources has already contributed to swings in power supplies in grids across the country (for example, wholesale electricity prices have been subjected to wild swings). PJM Interconnection LLC, the regional transmission organization (RTO) that coordinates the movement of wholesale electric in 13 states and the District of Columbia, estimated that the eclipse could wipe out 2,500 megawatts of solar generation of its system. Fortunately, the eclipse will not last long enough (12:05 P.M. to 4:09 P.M. EST) to significantly affect the demand for fossil fuels. But it may cause wholesale electricity prices to spike, since it will occur at a time when demand tends to surge due to air conditioner use.