California ISO expects sunny outcome for grid during solar eclipse
As one of the nation’s most solar-connected electrical grids, the California Independent System Operator (ISO) announced that it is prepared for the Aug. 21 solar eclipse, which will cast a wide shadow on solar power plants. The ISO expects sufficient energy supplies and network reliability during the eclipse.
California has some of the most ambitious renewable energy goals in the nation, including reaching 33 percent renewable energy by 2020, and 50 percent by 2030. Currently, the ISO’s solar generation capacity is nearly 10,000 MW, and can serve up to 40 percent of the ISO’s load some days.
“I am confident in the technology of our market and grid, and in the expertise and abilities of our staff to manage the operational challenges associated with
the eclipse,” said ISO President and CEO Steve Berberich. “As we welcome increasing amounts of renewable energy on to the grid, we are learning much about emerging shifts in operations that will define the electric system of tomorrow. Our team is committed to keeping the power flowing for Californians, as we navigate the unusual circumstances presented by the eclipse.”
The eclipse will affect the ISO’s balancing area and Energy Imbalance Market (EIM) participants from about 9 a.m. to noon, reducing solar output from both utility-scale generation connected to the grid, and from rooftop solar installations that serve homes and businesses. As solar power production declines that morning, the ISO forecasts it will need to dispatch about 6,000 megawatts (MW) of power from alternative sources. For context, one MW of electricity powers about 1,000 homes.
The ISO, state energy leaders, the California Public Utilities Commission (CPUC) and California utilities have been planning for the loss of solar generation
during the eclipse for more than a year. Preparation has centered on analyzing the likely loss of solar energy and arranging procurement of additional
reserves and system resources, primarily from flexible ramping sources, such as hydropower and natural gas plants. The transfer capability among western EIM
participants is expected to offer additional flexibility.
“The eclipse presents some grid management challenges for California and the West, however, with detailed planning and engagement among all parties we are expecting no shortage of electricity or reliability incidents related to the eclipse,” said Nancy Traweek, ISO’s executive director of system operations.“Market participants are aware this is a rare and significant solar event, and they have worked closely with us to develop plans.”
Traweek said the ISO will use lessons learned from this eclipse to prepare for the next North American solar eclipse, which will occur in 2024.