California Eclipse Spurs Gas Generation: EIA

Natural gas-fired generation in California increased during the solar eclipse that passed across the continental United States on August 21, despite the fact that the heavily populated state was not even in the path of totality.

Solar output on the California Independent System Operator (CAISO) system fell while the sun was partially obscured, said the US government's Energy Information Administration (EIA) August 24. CAISO’s solar power output fell to a low of 3.6 GW for that hour, about 60% lower than normal. EIA added that much of the decrease in solar output was made up by increased power imports and increased generation from thermal -- mostly gas-fired -- units.

Californian thermal generation, almost all of which is fired by natural gas in the CAISO area, increased by 3.7 GW during the eclipse.

Imports of electricity increased by 2.2 GW during the hour of the eclipse as CAISO drew power from neighbouring generators.

The path of totality during the August 21 US eclipse was a line from Oregon on the west coast to South Carolina on the east coast. The next total eclipse in the US will be on April 8 2024 and run from Texas to Maine, but also include parts of Mexico and Canada. 

Lessons from CAISO's experience may help the UK's National Grid, which said two weeks ago it had begun planning for the next significant UK solar eclipse (also partial).... nine years from now on August 12 2026 at 7.10pm local time (6.10pm GMT). It has already predicted that solar generation that day will drop by 2.0-3.5 GW during the event if there is a clear sky. A clear sky however is a more guaranteed phenomenon in California than in Britain.

Mark Smedley