Shortly after 4:55 PM on Sept. 6, California’s electricity grid set a new record. Briefly, residents and businesses were consuming electricity at a rate of 51,426 million watts, and the grid was stretched to its limit. Were it not for consumers reducing consumption in response to an urgent plea texted to 30 million cellphones, rolling outages initiated by system operator CAISO could have spiraled into a system-wide outage, shutting down the state and all of its businesses, and putting public health in jeopardy.
On electricity grids, supply of electricity must, at all times, be adjusted to meet demand precisely – no more, no less. For determining what led to California’s near-disaster, the image above is revealing:
- The top line (blue and red) shows demand – how much electricity consumers were using during that day.
- The lines below it show the various components of supply – what sources were used to meet demand (the heights of each of these lines added together is equal to the height of the demand line at any given time).
- During peak demand, over half of California’s electricity was being supplied by natural gas-fired electricity. At that time, gas plants were releasing 11,600 tons of CO2 into the air per hour.
- One-fourth of peak demand was met by wind and solar.
- Three-fourths of CA electricity imports are generated by out-of-state gas and coal plants.
- Assistance provided by batteries was negligible (1.9%).
- Between 9AM and 4PM solar generation was curtailed (deliberately limited) to 14,000 megawatts, so that natural gas could be ramped up in time to provide missing power after the sun went down.
- California reached peak consumption nearly ½ hour after CAISO’s plea to reduce consumption was issued.
Most forms of renewable electricity, including wind and solar, are intermittent – they aren’t always available to meet demand. In contrast, dispatchable sources like natural gas, coal, and nuclear, with an abundant supply of fuel in store, may be dispatched as needed.
California’s grid mix that day shows that, without nuclear and gas-fired electricity, California would be left at the mercy of the sun and wind for its power. It shows that dispatchable electricity will always be necessary to assure grid reliability, and that without the carbon-free electricity provided by Diablo Canyon and a new generation of advanced nuclear plants, meeting our state’s ambitious climate goals will be impossible.
- Grid Expert: Replacing Diablo Canyon Nuclear Plant with Renewables ‘Can’t Be Done’ - January 28, 2023
- Lessons Learned From California’s Averted Power Crisis - September 21, 2022
- The Failure of California Electricity Policy, Part 2 - May 2, 2022